Cementitious binder composition comprising autoclaved aerated concrete

Abstract

A cementitious binder composition for a concrete, grout or mortar, comprising: (A) At least 5.0 wt.%, preferably at least 10.0 wt.% but lower than 70.0 wt.%, preferably lower than 60.0 wt.% of a Supplementary Cementitious Material; (B) At least 0.5 wt.%, preferably at least 2.0 wt.%, more preferably at least 10.0 wt.% but lower than 50.0 wt.%, preferably lower than 35.0 wt.% of a comminuted Autoclave Aerated Concrete (AAC), wherein said comminuted Autoclave Aerated Concrete has a D50 value of at most 30 µm, preferably at most 15 µm wherein; and (C) At least 5.0 wt.%, preferably at least 10.0 wt.% but less than 90.0 wt.%, preferably less than 75.0 wt.% of a cement.

Description

CEMENTITIOUS BINDER COMPOSITION COMPRISING AUTOCLAVED AERATED CONCRETETechnical Field

[0001] The present invention relates to the field of a cement-based binder, in particular a cementitious binder composition for a mortar, grout or a concrete. The present invention further relates to a mortar, grout or concrete composition comprising said cementitious binder composition or processes for manufacturing said cementitious binder composition and a premix for said cementitious binder composition.Background Art

[0002] Thanks to its high versatility and durability, as well as relatively low price, concrete has become one of the most commonly used construction materials worldwide. However, its production, mainly through Ordinary Portland Cement (OPC) manufacturing, contributes significantly to environmental issues, causing up to 8% of global CO2 emissions. It is estimated that in 2023, around 785 kg CO2eq was emitted per metric tonne of cement produced(https: / / cembureau.eu / media / kuxd32gi / cembureau-2050-roadmap_final- version_web.pdf). With increasing demand for construction materials, there is a growing need to address these environmental impacts. Strategies include improving energy efficiency, exploring alternative materials, and adopting carbon capture technologies (Yang et al., https: / / doi.Org / https: / / doi.org / 10.1016 / j.jclepro.2014.03.018).

[0003] Supplementary Cementitious Materials (SCMs) are widely used in cement and concrete as partial replacement of clinker (CEM I) in binder material, thereby reducing the carbon footprint of concrete. SCMs encompass various inorganic materials that contribute to the properties of concrete. These materials can be categorized as inert, latent hydraulic, or pozzolanic. Inert SCMs (e.g. milled limestone) serve as fillers, filling voids and promoting microstructural densification in cement-based products. Latent hydraulic SCMs, such as those rich in calcium and silicon oxides (e.g. ground granulated blast furnace slag (GGBFS herein after)), undergo a reaction with water to produce calcium-silicate hydrate (C-S-H) or calcium-aluminum-silicate hydrate (C-A-S-H) gels when the pH is high enough (for example, in the presence of OPC). The pozzolanic reaction occurs when pozzolans, which are siliceous or siliceous aluminous materials(e.g. fly ash from coal energy plants) lacking inherent cementitious properties, interact with cement, consuming Ca(OH)2 generated during hydration and resulting in the formation of C-S-H and C-A-S-H gels and microstructural densification.

[0004] GGBFS and fly ash constitute the most used SCMs and have been defined in compositions in the cement European standard EN 197-1 (2011). However, stricter environmental regulations have led to closures of coal combustion plants in Europe, reducing the availability of coal fly ash in regions like the Benelux (https: / / www.greenpeace.org / belgium / nl / story / 1334 / belgie-neemt-definitief-afscheid- van-steenkool / ). Meanwhile, many blast furnaces in the Ell are nearing the end of their lifespans, potentially leading to shortages of GGBFS. Greener alternatives such as Direct Reduction-Electric Arc Furnace (DR-EAF) are being explored to replace conventional blast furnaces. To achieve carbon neutrality in iron steelmaking, hydrogen direct reduction is also under investigation. Both alternatives do not produce blast furnace slags. These shifts in the industry landscape, coupled with increasing demand for SCMs in countries like China and India, is exacerbating the scarcity of GGBFS and fly ash, prompting the search for alternative SCMs (https: / / www.concrete4change.com / pressrelease / barriers-to-net-zero-concrete-fly-ash- and-granulated-blast-furnace-slag-shortage).

[0005] Amongst the alternatives to GGBFS and fly ash, calcined clays have gained increasing attention in the recent years. Clays are widely abundant around the world and the heating step necessary to make them reactive does not release any chemically bounded CO2 and is done at relatively low temperatures (650 - 850°C) compared to clinker production (1450°C) (Snellings et al., https: / / doi.Org / 10.2138 / rmg.2012.74.6). The LC3 system (Limestone Calcined Clay Cement) constitutes a promising way to make use of calcined clays through their combination with milled limestone and OPC. The three primary components (i.e. clinker, calcined clay, and limestone) enable high clinker replacement rates and results in a refined and interconnected microstructure (Antoni et al., https: / / doi.Org / https: / / doi.org / 10.1016 / j.cemconres.2012.09.006). Despite this advantage, the LC3 systems present some challenges, the technology is still fully based on depleting primary raw materials and relies on the local availability of medium to high purity clay deposits. While it has a lower footprint compared to the clinker production, a large amount of energy is still required to calcine the clay materials (accounting for about 200 - 400kg CO2 per ton of calcined clay (Martinez et al, DOI 10.1088 / 2515- 7620 / acccd8)). A change of infrastructure and, consequently, large investments in calcination plants are also required. Regarding, the control of the rheology, it ischallenging (Abdulqader et al., https: / / doi.Org / https: / / doi.org / 10.1016 / j.jmrt.2023.06.114) due to the high-water demand of the calcined clays, which requires to either increase the water to binder ratio (impacting in turn the strength and durability of the concrete) or use of large amounts of superplasticizers (increasing the price).

[0006] Due to the increasing scarcity of GGBFS and fly ash as well as due to the aforementioned disadvantages of calcined clays, some industrial by-products or waste streams have been identified as having great potential to serve as an alternative for calcined clays, GGBFS and fly ash, one of them being autoclaved aerated concrete. The use of autoclaved aerated concrete (AAC herein after) coming from secondary streams has been investigated in literature. Typical applications which have been explored are AAC as raw material for the clinker production of Portland cement (Schoon et al., D0l:10.1016 / j.conbuildmat.2013.07.083), and the use of AAC as sand replacement or as partial replacement for OPC (Gyurko et al, D0l:10.1016 / j.jclepro.2019.04.357). One critical element in this replacement is the sulphate-leaching. This has been studied by Bergmans et al, which shows the critical buffering capacity of OPC for sulphates (Bergmans et al, D0l:10.1016 / j.conbuildmat.2016.02.075).

[0007] The use of AAC as partial and sole OPC replacement has already been documented i.e. IN202341013457 or IN202341059140. The fineness of the reported particles in the nanometric ranges act as nano-silica which support the pozzolanic reaction with pure Ordinary Portland cement. This disclosure is silent on a compositional range which allows a large replacement of the OPC fraction while keeping an appropriate mechanical behavior, resulting from the compatibility of the SCMs with the fine AAC material. Furthermore, these publications do not address the fact that a higher level of OPC replacement is sought to lower the environmental impact of cementitious bound building materials. DE-202018105762-U1 discloses concrete mixtures using recycled materials such as either AAC or SCMs to partially replace traditional cement and aggregates, enhancing sustainability.

[0008] Currently, secondary streams, end-of-life waste or production waste of autoclaved aerated concrete are not valorised. Nevertheless, the worldwide capacity of AAC is estimated at 450Mm3per year, which is partially reintegrated in the material recycle loop. Nowadays, AAC streams are not treated as a normal construction or demolition waste stream, but as a special waste stream, due to their high porosity, low strength and high sulphate-leaching. The latter is critical for environmental purposes as it is detrimental for the ecosystem. It has been considered in the past to immobilize the AAC by cementing it. However, such an intervention is limited in combination withOrdinary Portland Cement due to the sensitivity to sulphate-based deterioration mechanisms such as delayed ettringite formation or thaumasite formation. As a consequence, secondary AAC streams will in practice be mostly discarded and stored on a separate landfill.

[0009] In view of the large production capacity mentioned above and the potential of the material, there therefore remains a need for a composition that allows the reintegration of autoclaved aerated concrete in the material loop, preferably by using said material as a partial replacement of carbon dioxide intensive clinker. There further remains a need for such a composition to have an acceptably low value for sulphate leaching, enabling the use of such a composition as a building material.Summary of the invention

[0010] The inventors have surprisingly found that the composition according to the present invention fulfils the above-mentioned needs and overcomes the above- mentioned disadvantages.

[0011] In an aspect of the present invention, there is provided a cementitious binder composition for a concrete, grout or mortar, said cementitious binder composition comprising or consisting of:(A) at least 5.0 wt.%, preferably at least 10 wt.%, most preferably at least 15.0 wt.%, but lower than 70.0 wt.%, preferably lower than 60.0 wt.% of a Supplementary Cementitious Material, preferably said Supplementary Cementitious Material being at least 1.0 wt.%, preferably at least 2.0 wt.%, more preferably at least 5.0 wt.%, and most preferably at least 8.0 wt.% amorphous, in particular glassy, preferably said Supplementary Cementitious Material comprising:- at least 15.0 wt.%, preferably at least 20.0 wt.%, more preferably at least 25.0 wt.%, most preferably at least 30.0 wt.% but at most 70.0 wt.%, preferably at most 65.0 wt.%, most preferably at most 60.0 wt.% of silicon- containing compounds when expressed in the form of SiC>2, with respect to the total weight of the Supplementary Cementitious Material, and- at least 7.5 wt.%, preferably at least 10.0 wt.%, more preferably at least 12.5 wt.%, most preferably at least 15.0 wt.% but at most 40.0 wt.%, preferably at most 37.5 wt.%, more preferably at most 35.0 wt.%, even more preferably at most 32.5 wt.% most preferably at most 30.0 wt.% ofaluminum-containing compounds when expressed in the form of AI2O3, with respect to the total weight of the Supplementary Cementitious Material; and(B) At least 0.5 wt.%, preferably 2.0 wt.%, more preferably at least 5.0 wt.%, most preferably at least 10.0 wt.%, but lower than 50.0 wt.%, preferably lower than 35.0 wt.% of a comminuted Autoclave Aerated Concrete, preferably said comminuted Autoclave Aerated Concrete comprising;- between 10.0 wt.% and 40.0 wt.%, preferably between 15.0 wt.% and 30.0 wt.% of calcium-containing compounds, when expressed in the form of CaO with respect to the total weight of the comminuted Autoclave Aerated Concrete, and- between 30.0 wt.% and 60.0 wt.%, preferably between 35.0 wt.% and 50.0 wt.% of silicon-containing compounds when expressed in the form of SiC>2, with respect to the total weight of the comminuted Autoclave Aerated Concrete, more preferably wherein said comminuted Autoclave Aerated Concrete has a D50 value of at most 30 pm, preferably at most 15 pm; and (C) At least 5.0 wt.%, preferably at least 10.0 wt.%, most preferably at least 15.0 wt.%, but less than 90.0 wt.%, preferably less than 75.0 wt.% of a cement, preferably said binder composition having at least 5.0 wt.%, preferably at least 10.0 wt.%, most preferably at least 15.0 wt.%, but less than 90.0 wt.%, preferably less than 75.0 wt.% of calcium silicate mineral phases [SCaO.SiCh] and [2CaO.SiC>2].

[0012] According to specific embodiments of the invention, the cementitious binder composition comprises one or more of the following technical features:• the Supplementary Cementitious Material (A) has a D50 value of at most 30 pm, preferably at most 15pm;• the Supplementary Cementitious Material (A) is selected from the list consisting of: pumices; ashes; zeolitized tuffs; diatomaceous earths; burned or calcined clays; burned shales; fly ashes; ironmaking slags including smelter slags and blast furnace slags, such as GGBFS; silica fumes; primary and secondary steelmaking slags; non-ferrous slags, such as Si-slag; bottom ashes; waste glass; municipal waste incineration ashes; biomass combustion ashes, and combinations thereof; the cement is:- an Ordinary Portland cement (OPC), in particular Portland cement (OEM I) according to EN 197-1 (2011)), or- a Blended cement, in particular, selected from the group consisting of Portland composite cement (OEM II as EN 197-1 (2011)), blast furnace slag cement (OEM III as EN 197-1 (2011)), pozzolanic cement (OEM IV as EN 197-1 (2011)), slag-pozzolanic cement (OEM V as EN 197-1 (2011)), composite cement (such as OEM ll / C-M (LL,S) and OEM VI as EN 197-5 (2021)), cement with recycle building materials (OEM II and OEM VI as EN 197-6 (2023)), and combinations thereof, or- a combination of the Ordinary Portland cement and the Blended cement, the weight ratio of said Supplementary Cementitious Material (A) to said comminuted Autoclave Aerated Concrete (B), meaning (A):(B), is at least 1 .0:4.0, preferably at least 1 .0:2.0 and at most 4.0: 1.0; the weight ratio of a combination of said Supplementary Cementitious Material (A) and said comminuted Autoclave Aerated Concrete (B) with regard to said cement (C), meaning ((A)+(B)) : (C), is at least 1 :19, preferably is at least 1.0:9.0, even more preferably is at least 1.0:4.0; a flow improving agent (D) is selected from the list comprising: a naphthalene- based superplasticizer; a lignosulfonate; a protein, such as casein; a naphthalene sulphonate; a melamine-based superplasticizer; a polycarboxylate ether (PCE) or polyacrylate ether (PAE) based superplasticizer, a salt or derivative thereof; and mixtures thereof; the cementitious binder composition further comprises at least 2.0 wt.% with reference to the total weight of said binder composition but lower than 50.0 wt.% with reference to the total weight of said binder composition of a binding compound (E); a binding compound (E) is selected from the list consisting of an ash, a clay, a calcined clay, a distinct metallurgical slag, a mine tailing, a quartz filler, bauxite residue, and mixtures thereof; the Supplementary Cementitious Material (A) is further at least 30.0 wt.% amorphous, preferably at least 60.0 wt.% amorphous, in particular glassy; the Supplementary Cementitious Material (A) and / or the cement (C) comprises CaCCh issued from a different source than the CaCCh from the comminutedAutoclave Aerated Concrete (B); the Supplementary Cementitious Material (A) comprises at least 15.0 wt.%, preferably at least 20.0 wt.%, most preferably at least 25.0 wt.% of calcium- containing compounds when expressed in the form of CaO, with respect to the total weight of the Supplementary Cementitious Material (A); the Supplementary Cementitious Material (A) comprises at most 40.0 wt.%, preferably at most 35.0 wt.%, most preferably at most 30.0 wt.%, in particular at most 25.0 wt.% of calcium-containing compounds when expressed in the form of CaO, with respect to the total weight of the Supplementary Cementitious Material (A); the Supplementary Cementitious Material (A) comprises an amount of aluminum-containing compounds when expressed in the form of AI2O3 and an amount of iron-containing compounds when expressed in the form of Fe2Oa, wherein the sum of both amounts forms at least 10.0 wt.%, preferably at least 12.5 wt.%, and most preferably at least 15.0 wt.% of the total weight of said Supplementary Cementitious Material (A); the Supplementary Cementitious Material (A) comprises at least 4.0 wt.%, preferably at least 5.0 wt.%, more preferably at least 6.0 wt.%, and most preferably at least 7.0 wt.% of manganese-containing compounds when expressed in the form of MnO, but less than 21 .0 wt.%, preferably less than 15.0 wt.% with respect to the total weight of the Supplementary Cementitious Material (A); the Supplementary Cementitious Material (A) consists in GGBFS, said GGBFS preferably having CaO (30.0-50.0 wt.%), SiO2 (28.0-38.0 wt.%), AI2O3 (8.0-24.0 wt.%), and MgO (1.0-18.0 wt.%) or the Supplementary Cementitious Material (A) does not comprise GGBFS; the Supplementary Cementitious Material (A) has a weight ratio of SiO2:CaO of at least 0.6, preferably at least 0.7, more preferably at least 0.8, even more preferably at least 0.9, most preferably at least 1.0, in particular at least 1.1 , more particularly at least 1.2; the comminuted Autoclave Aerated Concrete (B) comprises at least 15.0 wt.%, preferably at least 17.5 wt.%, most preferably at least 20.0 wt.% of calcium- containing compounds when expressed in the form of CaO, with respect to thetotal weight of the comminuted Autoclave Aerated Concrete (B); the comminuted Autoclave Aerated Concrete (B) comprises at most 35.0 wt.%, preferably at most 32.5 wt.%, and most preferably at most 30.0 wt.% of calcium- containing compounds when expressed in the form of CaO, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B); the comminuted Autoclave Aerated Concrete (B) comprises at least 35.0 wt.%, preferably at least 37.5 wt.%, and most preferably at least 40.0 wt.% of silicon- containing compounds when expressed in the form of SiC>2, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B) and / or at most 55.0 wt.%, preferably at most 52.5 wt.%, and most preferably at most 50.0 wt.% of silicon-containing compounds when expressed in the form of SiC>2, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B); the comminuted Autoclave Aerated Concrete (B) comprises at least 0.5 wt.%, preferably at least 2.0 wt.%, and most preferably at least 3.0 wt.% of sulphur- containing compounds when expressed in the form of SO3, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B) and / or at most 10.0 wt.%, preferably at most 9.0 wt.%, and most preferably at most 8.0 wt.% of sulphur-containing compounds when expressed in the form of SO3, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B); the comminuted Autoclave Aerated Concrete (B) has a weight ratio of SiO2:CaO of at least 1.0: 1.0, preferably at least 1.2: 1.0, and most preferably at least 1.4:1.0; the comminuted Autoclave Aerated Concrete (B) further contains at least one carbonate, preferably, said comminuted Autoclave Aerated Concrete (B) containing at least 5.0 wt.%, more preferably at least 10.0 wt.% and most preferably at least 15.0 wt.% of said at least one carbonate, with regard to the total weight of the comminuted Autoclave Aerated Concrete (B), in particular the at least one carbonate being CaCCh; the comminuted Autoclave Aerated Concrete (B) further comprises or consists of a powdery material, having a D50 value smaller than 30 pm, more preferably smaller than 25 pm, even more preferably smaller than 20pm, more preferably smaller than 15pm, and most preferably smaller than 10 pm and / or powdery material having a Dmax value which is smaller than 65 pm, preferably smaller than 60 pm, more preferably smaller than 55 pm, even more preferably smallerthan 50 m and most preferably smaller than 45 pm;• the comminuted Autoclave Aerated Concrete (B) further comprises or consists of a fine Autoclave Aerated Concrete (B), wherein said fine Autoclave Aerated Concrete (B) has a D50 value smaller than 30 pm, more preferably smaller than 25 pm, even more preferably smaller than 20 pm, more preferably smaller than 15 pm, and most preferably smaller than 10 pm and / or has a Dmax value which is smaller than 65 pm, preferably smaller than 60 pm, more preferably smaller than 55 pm, even more preferably smaller than 50 pm and most preferably smaller than 45 pm;• the Supplementary Cementitious Material (A) is different from the comminuted Autoclave Aerated Concrete (B);• the comminuted Autoclave Aerated Concrete (B) is different from the cement (C);• the Cement (C) is different the Supplementary Cementitious Material (A).

[0013] For the above purpose, the invention is also directed to a process for the manufacturing of a premix for the cementitious binder composition, wherein said process comprises the steps of:- providing the Supplementary Cementitious Material (A);- providing the comminuted Autoclave Aerated Concrete (B);- mixing the Supplementary Cementitious Material (A), with the comminuted Autoclave Aerated Concrete (B) to form the premix.

[0014] For the above purpose, the invention is also directed to a process for the manufacturing of a cementitious binder composition according to the invention, said process comprises the step of:- optionally providing the cement (C);- optionally providing the premix;- optionally providing one or more compounds selected from the group comprising: the flow improving agent (D) and the binding compound (E);- mixing the premix with the cement (C) and optionally the one or more compounds selected from the group comprising: the flow improving agent (D) and the binding compound (E), to form said cementitious binder composition.

[0015] For the above purpose, the invention is also directed to a process for the manufacturing of the cementitious binder composition, wherein said process comprisesthe steps of:- providing the Supplementary Cementitious Material (A);- providing the comminuted Autoclave Aerated Concrete (B);- providing the cement (C);- optionally providing one or more compounds selected from the group comprising: the flow improving agent (D) and the binding compound (E);- mixing the Supplementary Cementitious Material (A), the comminuted Autoclave Aerated Concrete (B) and the cement (C) and optionally the one or more compounds selected from the group comprising: the flow improving agent (D) and the binding compound (E), to form said cementitious binder composition.

[0016] For the above purpose, the invention is also directed to a mortar, grout or concrete composition comprising the cementitious binder composition, and at least one of aggregate, sand, and water.

[0017] For the above purpose, the invention is also directed to a process for the manufacturing of a mortar, grout or concrete composition according to the invention, wherein said process comprises the steps of:- providing a cementitious binder composition according to the invention;- providing at least one of aggregate and sand;- mixing of said cementitious binder composition with of said aggregate and / or said sand, thereby forming a mixture;- adding of said water to said mixture.

[0018] For the above purpose, the invention is also directed to a use of a cementitious binder composition according to the invention for producing a mortar, grout or concrete composition.

[0019] For the above purpose, the invention is also directed to a cementitious binder precursor composition for a cementitious binder composition for a concrete, grout or mortar, said cementitious binder precursor composition comprising or consisting of:(A) At least 7.0 wt.% but lower than 85.0 wt.%, preferably lower than 70.0 wt.% of a Supplementary Cementitious Material, preferably said Supplementary Cementitious Material being at least 1.0 wt.%, preferably at least 2.0 wt.%, more preferably at least 5.0 wt.%, and most preferably at least 8.0 wt.% amorphous, in particular glassy, preferably said Supplementary Cementitious Material comprising:- at least 15.0 wt.%, preferably at least 20.0 wt.%, more preferably at least 25.0 wt.%, most preferably at least 30.0 wt.% but at most 70.0 wt.%, preferably at most 65.0 wt.%, most preferably at most 60.0 wt.% of silicon- containing compounds when expressed in the form of SiC>2, with respect to the total weight of the Supplementary Cementitious Material (SCM) and- at least 7.5 wt.% , preferably at least 10.0 wt.%, more preferably at least 12.5 wt.%, most preferably at least 15.0 wt.% but at most 40.0 wt.%, preferably at most 37.5 wt.%, more preferably at most 35.0 wt.%, even more preferably at most 32.5 wt.% most preferably at most 30.0 wt.% of aluminum-containing compounds when expressed in the form of AI2O3, with respect to the total weight of the Supplementary Cementitious Material (SCM); and(B) At least 2.0 wt.% but lower than 70.0 wt.% of a comminuted Autoclave Aerated Concrete, preferably said comminuted Autoclave Aerated Concrete comprising between 10.0 wt.% and 40.0 wt.%, preferably between 15.0 wt.% and 30.0 wt.% of calcium-containing compounds, when expressed in the form of CaO, and between 30.0 wt.% and 60.0 wt.%, preferably between 35.0 wt.% and 50.0 wt.% of silicon-containing compounds when expressed in the form of SiC>2, with respect to the total weight of the comminuted Autoclave Aerated Concrete (AAC), more preferably said comminuted Autoclave Aerated Concrete having a D50 value of at most 30 pm, preferably at most 15 pm.

[0020] According to specific embodiments of the invention, the cementitious binder precursor composition comprises one or more of the following technical features:• the Supplementary Cementitious Material (A) has a D50 value of at most 30 pm, preferably at most 15pm;• the Supplementary Cementitious Material (A) is selected from the list consisting of: pumices; ashes; zeolitized tuffs; diatomaceous earths; burned or calcined clays; burned shales; fly ashes; ironmaking slags including smelter slags and blast furnace slags, such as GGBFS; silica fumes; primary and secondary steel slags; non-ferrous slags, such as Si-slag; bottom ashes; waste glass; municipal waste incineration ashes; biomass combustion ashes, and combinations thereof; the weight ratio of said Supplementary Cementitious Material (A) to said comminuted Autoclave Aerated Concrete (B), meaning (A):(B), is at least 1 .0:4.0, preferably at least 1 .0:2.0 and at most 4.0: 1.0;the Supplementary Cementitious Material (A) is further at least 30.0 wt.%, preferably at least 40.0 wt.%, more preferably at least 50.0 wt.%, most preferably at least 60.0 wt.% amorphous, in particular glassy; the Supplementary Cementitious Material (A) comprises CaCCh issued from a different source than the CaCCh from the comminuted Autoclave Aerated Concrete (B); the Supplementary Cementitious Material (A) comprises at least 15.0 wt.%, preferably at least 20.0 wt.%, most preferably at least 25.0 wt.% of calcium- containing compounds when expressed in the form of CaO, with respect to the total weight of the Supplementary Cementitious Material (A); the Supplementary Cementitious Material (A) comprises at most 40.0 wt.%, preferably at most 35.0 wt.%, most preferably at most 30.0 wt.%, in particular at most 25% of calcium-containing compounds when expressed in the form of CaO, with respect to the total weight of the Supplementary Cementitious Material (A); the Supplementary Cementitious Material (A) comprises an amount of aluminum-containing compounds when expressed in the form of AI2O3 and an amount of iron-containing compounds when expressed in the form of Fe2Oa, wherein the sum of both amounts forms at least 10.0 wt.%, preferably at least 12.5 wt.%, and most preferably at least 15.0 wt.% of the total weight of said Supplementary Cementitious Material (A); the Supplementary Cementitious Material (A) comprises at least 4.0 wt.%, preferably at least 5.0 wt.%, more preferably at least 6.0 wt.%, and most preferably at least 7.0 wt.% of manganese-containing compounds when expressed in the form of MnO, but less than 21 .0 wt.%, preferably less than 15.0 wt.% with respect to the total weight of the Supplementary Cementitious Material (A); the Supplementary Cementitious Material (A) consists in GGBFS, said GGBFS preferably having CaO (30.0-50.0 wt.%), SiO2 (28.0-38.0 wt.%), AI2O3 (8.0-24.0 wt.%), and MgO (1.0-18.0 wt.%) or the Supplementary Cementitious Material (A) does not comprise GGBFS; the Supplementary Cementitious Material (A) has a weight ratio of SiO2:CaO of at least 0.6, preferably at least 0.7, more preferably at least 0.8, even morepreferably at least 0.9, most preferably at least 1.0, in particular at least 1.1 , more particularly at least 1.2; the comminuted Autoclave Aerated Concrete (B) comprises at least 15.0 wt.%, preferably at least 17.5 wt.%, most preferably at least 20.0 wt.% of calcium- containing compounds when expressed in the form of CaO, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B); the comminuted Autoclave Aerated Concrete (B) comprises at most 35.0 wt.%, preferably at most 32.5 wt.%, and most preferably at most 30.0 wt.% of calcium- containing compounds when expressed in the form of CaO, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B); the comminuted Autoclave Aerated Concrete (B) comprises at least 35.0 wt.%, preferably at least 37.5 wt.%, and most preferably at least 40.0 wt.% of silicon- containing compounds when expressed in the form of SiO2, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B) and / or at most 55.0 wt.%, preferably at most 52.5 wt.%, and most preferably at most 50.0 wt.% of silicon-containing compounds when expressed in the form of SiC>2, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B); the comminuted Autoclave Aerated Concrete (B) comprises at least 0.5 wt.%, preferably at least 2.0 wt.%, and most preferably at least 3.0 wt.% of sulphur- containing compounds when expressed in the form of SO3, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B) and / or at most 10.0 wt.%, preferably at most 9.0 wt.%, and most preferably at most 8.0 wt.% of sulphur-containing compounds when expressed in the form of SO3, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B); the comminuted Autoclave Aerated Concrete (B) has a weight ratio of SiO2:CaO of at least 1.0: 1.0, preferably at least 1.2: 1.0, and most preferably at least 1.4:1.0; the comminuted Autoclave Aerated Concrete (B) further contains at least one carbonate, preferably said comminuted Autoclave Aerated Concrete (B) containing at least 5.0 wt.%, more preferably at least 10.0 wt.% and most preferably at least 15.0 wt.% of said at least one carbonate, with regard to the total weight of the comminuted Autoclave Aerated Concrete (B), preferably the at least one carbonate being CaCCh;• the comminuted Autoclave Aerated Concrete (B) further comprises or consists of a powdery material, having a D50 value smaller than 30 pm, more preferably smaller than 25 pm, even more preferably smaller than 20pm, more preferably smaller than 15pm, and most preferably smaller than 10 pm and / or powdery material having a Dmax value which is smaller than 65 pm, preferably smaller than 60 pm, more preferably smaller than 55 pm, even more preferably smaller than 50 pm and most preferably smaller than 45 pm;• the comminuted Autoclave Aerated Concrete (B) further comprises or consists of a fine Autoclave Aerated Concrete (B), wherein said fine Autoclave Aerated Concrete (B) has a D50 value smaller than 30 pm, more preferably smaller than 25 pm, even more preferably smaller than 20 pm, more preferably smaller than 15 pm, and most preferably smaller than 10 pm and / or has a Dmax value which is smaller than 65 pm, preferably smaller than 60 pm, more preferably smaller than 55 pm, even more preferably smaller than 50 pm and most preferably smaller than 45 pm;• the Supplementary Cementitious Material (A) is different from the comminuted Autoclave Aerated Concrete (B).

[0021] For the above purpose, the invention is also directed to a process for the manufacturing of the cementitious binder precursor composition, comprising the steps of:- providing the Supplementary Cementitious Material (A);- providing the comminuted Autoclave Aerated Concrete (B);- mixing the Supplementary Cementitious Material (A), with the comminuted Autoclave Aerated Concrete (B) to form said cementitious binder precursor composition.

[0022] It is an advantage of the cementitious binder composition according to the invention that a composition is provided which allows the reduction of carbon intensive materials such as OPC in a concrete, grout of mortar. Furthermore, said composition allows for a concentration reduction of SCMs, which have been used in the past for replacing OPC in concrete, grout or mortars, and which have become scarce in more recent years. The invention is based on the observation that the combination of an AAC and a SCM as described herein, allows to successfully partially replace OPC as a binder for producing a concrete, grout or mortar, wherein said concrete is characterized by a positive final mechanical strength and / or strength development profile during the first 28 days. The effect of the combination of the selected SCMs with AAC as a partialreplacement for OPC on the compressive strength of the final concrete product is unexpected when compared with OPC replacement by only one of said components. The observed synergistic effect illustrates that the addition of AAC cannot be attributed to a simple filler effect. On the contrary, the addition of AAC actively contributes to the build-up of compressive strength.

[0023] Advantageously, said cementitious binder compositions according to the invention allow for a high value recycling option of end-of-life or secondary AAC. Furthermore, the binder compositions as described herein advantageously allow for a lower leaching of sulphates and are therefore more tolerant for sulphate concentration. It is a further advantage that the binder composition described herein allows for the fabrication of a robust binder containing significant amount of fine AAC with low ecological footprint at economical scale. Moreover, the obtained binder has a similar workability as conventional concrete and can be used as replacement for conventional blended cement types. The used infrastructure is the same or substantially the same as in a conventional cement plant. The milling of the AAC and optionally the SCMs may require some adaptation in the plant.Brief description of the figures

[0024] These and other features and advantages of embodiments of the present invention will now be described in more detail with reference to the accompanying drawings, in which:

[0025] Figure 1 schematically illustrates compressive strength development for mortar compositions comprising GGBFS, at a constant OPC concentration.

[0026] Figure 2 schematically illustrates compressive strength development for mortar compositions comprising Si-slag and / or AAC, at a constant OPC concentration.

[0027] Figure 3 schematically illustrates compressive strength development for mortar compositions comprising SCM compounds other than in Examples 2 and 3, with or without partial replacement by AAC.Detailed description of the invention

[0028] The present invention will be described with respect to particular embodiments and with reference to certain figures, but the invention is not limited thereto but only by the claims.

[0029] In the context of the present invention, the term “comprising” should not be interpreted as excluding features or elements other than those explicitly mentioned. It should be construed as specifying the presence of the features or elements indicated, but does not exclude the presence or addition of one or more other features or elements. Thus, the scope of the expression "a product comprising A and B" should not be limited to products consisting only of A and B. Similarly, a composition comprising components A and B should not be limited to compositions consisting only of components A and B. Accordingly, the term "comprising" and "including" encompass the terms more restrictive “consisting essentially of” and “consisting of”.

[0030] In the context of the present invention, if an element or component is said to be selected from a list of recited elements or components, it should be understood that the element or component can also be any one of the individual recited elements or components in said list, or can also be selected from a group consisting of any two or more of the explicitly listed elements or components.

[0031] Further advantages and characteristics of the invention will become apparent from the following description of a number of preferred embodiments of protective clothing according to the invention. However, the following description is merely illustrative and is not intended to limit the scope of the invention as determined by the claims.

[0032] An aspect of the invention relates to a cementitious binder composition for a concrete, grout or mortar, comprising: (A) a Supplementary Cementitious Material (SCM), (B) an Autoclave Aerated Concrete (AAC), and (C) a cement such as OPC.

[0033] The invention is inter alia based on the insight that the combination of AAC and an appropriate SCM allows for at least a partial replacement of OPC by said combination in a composition for a mortar, grout or concrete. More in particular, it has been found that AAC can partially replace a SCM as described herein in a binder composition surprisingly without experiencing a loss in final compressive strength of the concrete obtained, with regard to a binder composition containing only said SCM and OPC. It has even been found that at least one of the final compressive strength (measured after 28 days) and / or the strength development profile over time (being the first 28 days) is affected positively when replacing said OPC with a combination of a SCM and an AAC, instead of with the SCM only. In other words, the invention is inter alia based on the unexpected positive and synergistic effect on compressive strength between the SCM as described herein and the AAC. Advantageously, this allows for a reduced use of SCMs, some which have become more scarce and / or expensive in recentyears, by a waste product (AAC) which at this point has no further use.

[0034] The compositions according to the present invention have been found to lead to concretes, grouts and mortars, achieving sufficient levels of compressive strength within the required time frame, i.e. 28 days. The compositions further allow for the fabrication of a robust binder with a low carbon footprint at an economical scale. Moreover, the obtained binder allows a similar workability as in conventional concrete and can be used as a replacement for conventional blended cement types. The used infrastructure is the same or substantially the same as in a conventional cement plant. The milling of the SCMs and optionally ACC may require some adaptations.

[0035] The following terms are provided solely to aid in the understanding of the invention.

[0036] For the purpose of the invention, the term “binder” or “binder composition” refers herein to a composition or mixture of compounds or materials that holds or draws other materials together to form a cohesive whole mechanically. The binder composition preferably has this effect due to the addition of water. Herein, the term is used to describe such properties for the production of a mortar, grout or concrete, which is obtained upon combining such a binder composition with at least one of water, sand, and / or aggregate. Traditionally, the most frequent used binder for the production of concrete, grout or mortar is Ordinary Portland Cement (CEM I).

[0037] For the purpose of the invention, the term “slag” refers herein to a waste material produced during the smelting or refining of metals, which typically occurs by reaction of a flux with impurities. Slags as referred herein can advantageously be used to at least partially replace OPC in an inorganic composition for the purpose of making mortar, grout or concrete.

[0038] For the purpose of the invention, the term “sand” refers herein to so-called “sharp sand” or “construction sand” or “river sand”, and is an example of a so-called fine aggregate, having an average particle diameter ranging in size from 0.1 to 4.0 mm.

[0039] For the purpose of the invention, the term “aggregate” refers herein to so- called coarse aggregates which relate to particles having an average particle diameter greater than 4.00 mm. Aggregates as used herein typically relate to materials such as gravel, crushed stone, or recycled concrete. Coarse aggregates provide bulk to concrete, contributing to its strength and durability.

[0040] For the purpose of the invention, a particle size, which may be indicatedherein for SCM (A) or for AAC (B), expressed as Dxx < Y denotes a percentage (xx%) by weight of particles of said SCM (A) or AAC (B) having a particle size equal to or less than Y.

[0041] For example, SCM (A) having a D90 < 30 pm denotes that 90.0 wt.% of the particles of said SCM (A), as detailed herein, has a particle size equal to or less than 30 pm.

[0042] Furthermore, the term “Dmax” refers to the maximum particle size present in a sample of particles. In other words, it represents the largest size of particles within the distribution.

[0043] According to the invention, the cementitious binder composition for a concrete, grout or mortar, comprises a Supplementary Cementitious Material (A). In embodiments according to the invention, said cementitious binder composition for a concrete, grout or mortar comprises at least one Supplementary Cementitious Material (SCM).

[0044] For the purpose of the invention, the term “Supplementary Cementitious Material” or “SCM” refers herein to a material used as a partial replacement of a cement in particular an Ordinary Portland Cement for the purpose of improving properties of the concrete, grout or mortar and / or to reduce the ecological footprint of the material. As already mentioned herein, SCMs typically relate to inorganic materials that affect the properties of concrete, grout or mortar. SCMs can be categorized as inert (such as milled limestone ), latent hydraulic (such as GGBFS), or pozzolanic (such as fly ash).

[0045] In embodiments, said SCM (A) is selected from the following: pumices; ashes; zeolitized tuffs; diatomaceous earths; burned or calcined clays; burned shales; fly ashes; ironmaking slags including smelter slags and blast furnace slags, such as GGBFS; silica fumes; primary and secondary steel slags; non-ferrous slag, such as Sislag; bottom ash; waste glass; municipal waste incineration ashes; biomass combustion ashes; and combinations thereof.

[0046] In embodiments, said SCM is natural in origin. Alternatively, said SCM is artificially produced, preferably as a waste material, or by-product in a process.

[0047] In embodiments according to the invention, said SCM comprises at least 15.0 wt.%, preferably at least 20.0 wt.%, more preferably at least 25.0 wt.%, and most preferably at least 30.0 wt.% of silicon-containing compounds when expressed in the form of SiO2, with respect to the total weight of the SCM. It will further be understood thatthe SCM comprises at most 70.0 wt.%, preferably at most 65.0 wt.%, and most preferably at most 60.0 wt.% of silicon-containing compounds when expressed in the form of SiC>2, with respect to the total weight of the SCM.

[0048] In embodiments according to the invention, said SCM comprises at least 7.5 wt.%, preferably at least 10.0 wt.%, more preferably at least 12.5 wt.%, and most preferably at least 15.0 wt.% of aluminum-containing compounds when expressed in the form of AI2O3, with respect to the total weight of the SCM. It will further be understood that the SCM comprises at most 40.0 wt.%, preferably at most 37.5 wt.%, more preferably at most 35.0 wt.%, even more preferably at most 32.5 wt.% and most preferably at most 30.0 wt.% of aluminum-containing compounds when expressed in the form of AI2O3, with respect to the total weight of the SCM.

[0049] In embodiments according to the invention, said SCM comprises at least 15.0 wt.%, preferably at least 20.0 wt.%, most preferably at least 25.0 wt.% of calcium- containing compounds when expressed in the form of CaO, with respect to the total weight of the SCM. It will further be understood that the SCM comprises at most 40.0 wt.%, preferably at most 35.0 wt.%, more preferably at most 30.0 wt.%, in particular at most 25.0 wt.% of calcium-containing compounds when expressed in the form of CaO, with respect to the total weight of the SCM.

[0050] In embodiments according to the invention, said SCM (A) has a weight ratio of SiO2:CaO of at least 0.6, preferably at least 0.7, more preferably at least 0.8, even more preferably at least 0.9, most preferably at least 1.0, in particular at least 1.1 , more particularly at least 1.2.

[0051] In embodiments according to the invention, said SCM comprises an amount of aluminum-containing compounds when expressed in the form of AI2O3 and an amount of iron-containing compounds when expressed in the form of Fe2C>3, wherein the sum of both amounts forms at least 10.0 wt.%, preferably at least 12.5 wt.%, and most preferably at least 15.0 wt.% of the total weight of said SCM.

[0052] In embodiments according to the invention, said SCM comprises at least 4.0 wt.%, preferably at least 5.0 wt.%, more preferably at least 6.0 wt.%, and most preferably at least 7.0 wt.% of manganese-containing compounds when expressed in the form of MnO, but less than 21.0 wt.%, preferably less than 15.0 wt.% with respect to the total weight of the SCM. Manganese can thereby exhibit oxidation states from II to VII. As a consequence, manganese oxide can be present as e.g. MnO and Mn2O?.

[0053] In embodiments according to the invention, said SCM (A) relates at least toa ground granulated blast furnace slag (GGBFS). For the purpose of the invention, the term “GGBFS” refers herein to the slag by-product that is obtained during the smelting or refining of metal ore (typically iron ore) in a blast furnace. The chemical composition of GGBFS depends considerably on the conditions and the choice of raw materials for the process. The main components of GGBFS are typically CaO (30.0-50.0 wt.%), SiO2 (28.0-38.0 wt.%), AI2O3(8.0-24.0 wt.%), and MgO (1.0-18.0 wt.%).

[0054] In alternative embodiments, said SOM (A) consists of a GGBFS or said SOM (A) does not comprise GGBFS.

[0055] In embodiments according to the invention, said SOM (A) relates at least to a non-ferrous slag. For the purpose of the invention, the term “non-ferrous slag” refers herein to the slag by-product that is obtained during the smelting or refining of a nonferrous ore in a furnace. Its composition can vary depending on the type of non-ferrous metal being processed and the specific smelting or refining techniques used.

[0056] In alternative embodiments, said SOM (A) consists of a Non-ferrous slag.

[0057] In embodiments according to the invention, said SOM (A) comprises or consists of a Si-slag. For the purpose of the invention, the term “Si-slag” refers herein to a by-product from the manufacturing of a ferromanganese, ferromanganese-silicon- manganese alloy, silicon alloy or manganese alloy, usually obtained by reducing ore in a submerged arc furnace. Typically, a Si-slag will have a chemical composition comprising between 17.0-43.0 wt.% SiO2, 12.0-27.0 wt.% AI2O3, 17.0-44.0 wt.% CaO, 4.0- 9.0 wt.% MgO and 5.0-21.0 wt.% MnO.

[0058] In embodiments according to the invention, said SOM (A) comprises or consist of a calcined clay. For the purpose of the invention, the term “calcined clay” refers herein to pozzolanic materials that can be produced by calcining (e.g. at 650-750°C) natural clay minerals such as kaolinite. Typically, a calcined clay will contain between 40.0-75.0 wt.% SiO2 and 20.0-40.0 wt.% AI2O3, silica and alumina being the main components.

[0059] In embodiments according to the invention, said SCM (A) comprises or consist of a fly ash. For the purpose of the invention, the term “fly ash” refers herein to a coal combustion product, composed of the particulates that are driven out of coal-fired boilers together with the flue gases. The composition of fly ash can vary on whether the coal is bituminous, subbituminous or lignite. Typically, fly ash will contain between 20.0- 60.0 wt.% SiO2 and 5.0-35.0 wt.% AI2O3, with possibly significant additional concentrations of Fe2Os (5.0-35.0 wt.%) and CaO (1.0-40.0 wt.%).

[0060] Examples of SCMs and their chemical composition are given in Table 1. The values of the chemical composition are determined by X-ray fluorescence (XRF).

[0061] Preferably, the SCM consists, for a majority, of an amorphous phase, in particular glassy phase. It has been observed that the amorphous phase, in particular glassy phase, is more susceptible to dissolve in alkaline environment and will therefore advantageously result in a higher compressive strength development at a faster rate. Hence, it is preferred that the SCM has a relatively large fraction of amorphous content, in particular glass-content.

[0062] In embodiments according to the invention, said SCM is at least 30.0 wt.%, preferably at least 40.0 wt.%, more preferably at least 50.0 wt.%, and most preferably at least 60.0 wt.% amorphous. In other words, at least 30.0 wt.%, preferably at least 40.0 wt.%, more preferably at least 50.0 wt.%, and most preferably at least 60.0 wt.% of the SCM is amorphous, in particular glassy, with reference to the total weight of the SCM compound in the composition.

[0063] In embodiments according to the invention, the SCM contains a minority of mineral phases. Preferably, the total of said mineral phases form less than 70.0 wt.%, preferably less than 60.0 wt.%, more preferably less than 50.0 wt.%, and most preferably less than 40.0 wt.% of the SCM. The mineralogic constituents and amount of amorphous phases are determined by X-ray diffraction (XRD) and quantified via the Rietveld refinement method, referred to as QXRD. Table 2 shows examples of SCM and their mineralogical composition.

[0064] Preferably, said SCM (A) relates to a powdery material, having a D50 value smaller than 30 pm, more preferably smaller than 25 pm, even more preferably smaller than 20 pm, more preferably smaller than 15 pm, and most preferably smaller than 10 pm. Alternatively, said SCM (A) is also considered to be a fine SCM, wherein said “fine SCM” has a D50 value smaller than 30 pm, more preferably smaller than 25 pm, even more preferably smaller than 20 pm, more preferably smaller than 15 pm, and most preferably smaller than 10 pm. It has been found that the use of a fine SCM, having a D50 value as described herein, has a beneficial effect on the technical effects of the cementitious binder compositions described herein.

[0065] Said SCM (A) may be comminuted (e.g. milled, ground and / or crushed) into a fine, powdery material, prior to use in said cementitious binder composition. This can be done, but is not limited to, conventional milling techniques such as a ball mill (BM), a vertical roller miller (VRM) or a high-pressure grinding rolls mill (HPRG).

[0066] According to the invention, the cementitious binder composition for a concrete, grout or mortar, further comprises an Autoclave Aerated Concrete (B).

[0067] For the purpose of the invention, the term “Autoclave Aerated Concrete” or “AAC” refers herein to a cellular concrete building material. AAC products are typically obtained by curing a mixture of quartz sand (or pulverized fly ash), lime, OPC, water and an aluminum source with the addition of gypsum prior to place it in an autoclave. The aluminum powder or paste reacts with lime and water to generate hydrogen gas bubbles, creating the porous structure characteristic of AAC. AAC products have also been known as “autoclaved cellular concrete (ACC)”. AAC products have been marketed under commercial names such as Aircrete, Hebei, Aercon, Starken, Gasbeton, Airbeton, Durox, Siporex, Suporex, H+H and Ytong. Said products are considered to relate to AAC products as described herein.

[0068] The term “comminuted” refers to mill, grind and / or crush a substance into powder-like material.

[0069] In embodiments according to the invention, said AAC comprises at least 15.0 wt.%, preferably at least 17.5 wt.%, most preferably at least 20.0 wt.% of calcium- containing compounds when expressed in the form of CaO, with respect to the total weight of the AAC. It will further be understood that the AAC comprises at most 35.0 wt.%, preferably at most 32.5 wt.%, and most preferably at most 30.0 wt.% of calcium- containing compounds when expressed in the form of CaO, with respect to the total weight of the AAC.

[0070] In embodiments according to the invention, said AAC comprises at least 35.0 wt.%, preferably at least 37.5 wt.%, and most preferably at least 40.0 wt.% of silicon- containing compounds when expressed in the form of SiO2, with respect to the total weight of the AAC. It will further be understood that the AAC comprises at most 55.0 wt.%, preferably at most 52.5 wt.%, and most preferably at most 50.0 wt.% of silicon- containing compounds when expressed in the form of SiC>2, with respect to the total weight of the AAC.

[0071] In embodiments according to the invention, said AAC comprises at least 0.5 wt.%, preferably at least 2.0 wt.%, and most preferably at least 3.0 wt.% of sulphur- containing compounds when expressed in the form of SO3, with respect to the total weight of the AAC. It will further be understood that the AAC comprises at most 10.0 wt.%, preferably at most 9.0 wt.%, and most preferably at most 8.0 wt.% of sulphur- containing compounds when expressed in the form of SO3, with respect to the totalweight of the AAC.

[0072] In embodiments according to the invention, said AAC (B) has a weight ratio of SiC>2:CaO of at least 1.0: 1.0, preferably at least 1.2:1 , and most preferably at least 1.4:1.

[0073] An Example of an AAC and its chemical composition is given in Table 1 . The values of the chemical composition are determined by X-ray fluorescence (XRF).

[0074] In embodiments according to the invention, said AAC (B) further contains at least one carbonate. Preferably, said AAC (B) contains at least 5.0 wt.%, more preferably at least 10.0 wt.% and most preferably at least 15.0 wt.% of said at least one carbonate, with regard to the total weight of said AAC (B). In embodiments, said at least one carbonate is formed due to natural carbonation or accelerated carbonation of Ca(OH)2, C-S-H-gel, C-A-S-H-gel or tobermorite-like minerals.

[0075] Preferably, said at least one carbonate relates to CaCCh. Preferably, said CaCCh has the mineral form of at least one of the following mineral phases: calcite, vaterite, aragonite. In embodiments, at least part of the CaCCh is amorphous.

[0076] In embodiments according to the invention, said AAC (B) further contains an amount of CaSCh. More in particular, said AAC (B) comprises at least one of the following: CaSCh (anhydrite), alfa-CaSO^ W (alfa hemi-hydrate), beta-CaSO^ W (beta hemi-hydrate), CaSO4.2H2O (gypsum).

[0077] In preferred embodiments, said AAC (B) relates to a powdery material, having a D50 value smaller than 30 pm, more preferably smaller than 25 pm, even more preferably smaller than 20pm, more preferably smaller than 15pm, and most preferably smaller than 10 pm. Alternatively or additionally, said AAC (B) is also considered to be a fine AAC, wherein said “fine AAC” has a D50 value smaller than 30 pm, more preferably smaller than 25 pm, even more preferably smaller than 20 pm, more preferably smaller than 15 pm, and most preferably smaller than 10 pm. It has been found that the use of a fine AAC, having a D50 value as described herein, has a beneficial effect on the technical effects of the cementitious binder compositions described herein.

[0078] In preferred embodiments, said AAC (B) or fine AAC has a Dmax value which is smaller than 65 pm, preferably smaller than 60 pm, more preferably smaller than 55 pm, even more preferably smaller than 50 pm and most preferably smaller than 45 pm.

[0079] Preferably, the comminuted AAC relates to a fine particle AAC and has been crushed, ground, and / or milled prior to use in said cementitious binder composition, tohave an intended particle size distribution.

[0080] Values for particle size for various materials used in the examples can be found in Table 3.

[0081] According to the invention, the cementitious binder composition for a concrete, grout or mortar, comprises a cement.For the purpose of the invention, the term “cement” refers herein to a binding material for use in grout, mortar or concrete. The cement may be any type of cement:- an Ordinary Portland cement (OPC), in particular Portland cement (OEM I) according to EN 197-1 (2011), or- a Blended cement, in particular selected from the group consisting of Portland composite cement (OEM II as EN 197-1 (2011)), blast furnace slag cement (OEM III as EN 197-1 (2011)), pozzolanic cement (OEM IV as EN 197-1 (2011)), slag-pozzolanic cement (OEM V as EN 197-1 (2011)), composite cement (such as OEM ll / C-M (LL,S) and OEM VI as EN 197-5 (2021)), cement with recycle building materials (OEM II and OEM VI as EN 197-6 (2023)), and combinations thereof, or- a combination of the Ordinary Portland cement and the Blended cement, in embodiments, the cement is preferably an Ordinary Portland cement (OPC). More preferably, said cement relates herein to OEM I, according to EN 197-1 (2011).

[0082] In embodiments, the cement is preferably an Ordinary Portland cement (OPC). More preferably, said cement relates herein to CEM I, according to EN 197-1 (2011). Preferably the Ordinary Portland cement is composed for at least two thirds in mass of calcium silicates [3CaO.SiO2] and [2CaO.SiO2] (a.k.a. alite (C3S) and belite (C2S)), the remaining part comprising preferably AI2O3 and Fe2Oa - containing phases.

[0083] The grinding can be performed with each compound (A), (B), (C) taken individually or in combination (Co-grinding: (A)(B), (B)(C), (C)(A), or (A)(B)(C)), depending on the characteristics of the products and the plant constraints.

[0084] In embodiments according to the invention, said Supplementary Cementitious Material (A) relates to a component or components which are different from said Autoclave Aerated Concrete (B). Furthermore, it will be understood that the cement (C) relates to a component or components that are different from said SCM (A) and said AAC (B). Hence, it will be clear to the skilled person that there is no overlap between said at least SCM (A), said AAC (B), and said cement (C).

[0085] In embodiments according to the invention, said cementitious binder composition comprises at least 5.0 wt.%, preferably at least 10.0 wt.% and most preferably at least 15.0 wt.% but lower than 70.0 wt.%, preferably lower than 60.0 wt.% of the SCM (A), with respect to the total weight of the cementitious binder composition.

[0086] In embodiments according to the invention, said cementitious binder composition comprises at least 0.5 wt.%, preferably at least 2.0 wt.%, more preferably at least 5.0 wt.% and most preferably at least 10.0 wt.% but lower than 50.0 wt.%, preferably lower than 35.0 wt.% of the AAC (B), with respect to the total weight of the cementitious binder composition.

[0087] In embodiments according to the invention, said cementitious binder composition comprises at least 5.0 wt.%, preferably at least 10.0 wt.% and most preferably at least 15.0 wt.% but lower than 90.0 wt.%, preferably lower than 75.0 wt.% of the cement (C), with respect to the total weight of the cementitious binder composition.

[0088] In embodiments according to the invention, the weight ratio of said SCM (A) to said AAC (B), or (A):(B), is at least 1 .0:4.0, more preferably at least 1.0:2.0, even more preferably at least 1.0: 1.0, even more preferably at least 2.0:1.0. It will further be understood that said weight ratio of said SCM (A) to said AAC (B), or (A):(B), is at most 19.0:1.0, preferably at most 14.0:1.0, and most preferably at most 9.0:1.0.

[0089] In embodiments according to the invention, the weight of a combination of said SCM (A) and said AAC (B) with regard to said cement (C), or ((A)+(B)): (C), is at least 1.0:19.0, more preferably at least 1.0:9.0, even more preferably at least 1.0:4.0, even more preferably at least 1.0:2.0. It will further be understood that said weight ratio of said combination of said SCM (A) and said AAC (B) with regard to said cement (C), or ((A)+(B)):(C), is at most 9.0:1.0, more preferably at most 4.0:1.0, even more preferably at most 2.0:1.0.

[0090] In embodiments according to the invention, said cementitious binder composition comprises:- from 5.0 wt.% to 70.0 wt.% of said SCM (A), wherein said SCM (A) is a GGBFS;- from 2.0 wt.% to 50.0 wt.% of said AAC (B); and- from 2.0 wt.% to 75.0 wt.% of said Cement (C); wherein said Cement relates to OPC (CEM I).

[0091] In embodiments according to the invention, said cementitious binder composition further comprises a flow improving agent, which is selected from the list comprising: a naphthalene-based superplasticizer; a lignosulfonate; a protein, such ascasein; a naphthalene sulphonate; a melamine-based superplasticizer; a polycarboxylate ether (PCE) or polyacrylate ether (PAE) based superplasticizer, a salt or derivative thereof; and mixtures thereof.

[0092] In embodiments according to the invention, said cementitious binder composition further comprises at least one of the following: mine tailing, a quartz filler, bauxite residue, limestone filler, dolomite filler, and combinations thereof.

[0093] In other embodiments according to the invention, said cementitious binder composition consists of said Supplementary Cementitious Material (A), said comminuted Autoclave Aerated Concrete (B) and said cement (C) in particular Ordinary Portland Cement.

[0094] A first mixture comprising or consisting of the SCM compound (A) and the cement (C) can be prepared, thereby resulting in a blended cement according to for instance CEM lll / A (EN 197-1 (2011)) or CEM ll / C-M (LL,S) (EN 197-5 (2021)). The cementitious binder composition according to the present disclosure is then obtained by mixing said blended cement with the Autoclave Aerated Concrete (B).

[0095] It is understood that all definitions, preferences, embodiments and preferred embodiments hereinabove, also apply for all further aspects and embodiments, as described below.

[0096] An aspect of the invention relates to a process for the manufacturing of an cementitious binder composition as described herein, the process comprising the steps of:- providing a Supplementary Cementitious Material (A);- providing an Autoclave Aerated Concrete (B);- providing a cement (C), in particular Ordinary Portland Cement;- mixing at least 5.0 wt.%, preferably at least 10.0 wt.%, most preferably at least 15.0 wt.%, but lower than 70.0 wt.%, preferably lower than 60.0 wt.% of the Supplementary Cementitious Material (A), at least 5.5 wt.% , preferably at least 2.0 wt.%, preferably at least 5.0 wt.%, most preferably at least 10.0 wt.%, but lower than 50.0 wt.%, preferably lower than 35.0 wt.% of the comminuted Autoclave Aerated concrete (B) and at least 5.0 wt.%, preferably at least 10.0 wt.%, most preferably at least 15.0 wt.%, but lower than 90.0 wt.%, preferably lower than 75.0 wt.% of cement (C), wherein all wt.% are relative to the total weight of the cementitious binder composition.Although the components can be mixed in a random order, SCM (A) and AAC (B) are preferably premixed.An aspect of the invention relates to a process for the manufacturing of a premix for a cementitious binder composition as described herein, comprising the steps of: a) providing the Supplementary Cementitious Material (A); b) providing the Autoclave Aerated concrete (B); c) mixing preferably, from 9.1 wt.% to 97.2 wt.%, of the Supplementary Cementitious Material (A), with, preferably from 2.8 wt.% to 90.9 wt.%, of the Autoclave Aerated concrete (B) to form a premix, wherein all wt.% are relative to the total weight of the premix.

[0097] An aspect of the invention relates to a process for the manufacturing of an cementitious binder composition from a premix as defined here above, wherein said process comprises the step of mixing, preferably from 7.0 wt.% to 95.0 wt.%, of said premix with from 5.0 wt.% to 90.0 wt.% of a cement (C), in particular an Ordinary Portland Cement, as defined herein, to form said cementitious binder composition, wherein all wt.% are relative to the total weight of the cementitious binder composition.

[0098] An aspect of the invention relates to a mortar, grout or concrete composition comprising the cementitious binder composition as described herein and at least one of aggregate, sand, and water.

[0099] An aspect of the invention relates to a process for the manufacturing of a mortar, grout or concrete composition as defined herein, wherein said process comprises the steps of: a) providing a cementitious binder composition as defined herein; b) providing at least one of aggregate and sand; c) mixing from 1.0 wt.% to 20.0 wt.% of said cementitious binder composition with from 0.0 wt.% to 95.0 wt.% of said aggregate and / or from 0.0 wt.% to 95.0 wt.% of said sand, d) adding from 1.0 wt.% to 50.0 wt.% of said water to said mixture of cementitious binder composition and at least one of said aggregate and said sand, wherein all wt.% are relative to the total weight of the mortar, grout or concrete composition.

[0100] An aspect of the invention relates to the use of a cementitious binder composition as defined herein for producing a mortar, grout or concrete composition as defined herein.Experimental Results

[0101] The invention will be now described in more details with reference to the following examples, whose purpose is merely illustrative and not intended to limit the scope of the invention.Example 1 : composition of the SCM compounds used in further examples

[0102] The following raw materials as summarized in Table 1 , have been used as SCM compounds in the experiments below, wherein the components are expressed in weight, and wherein e.g. “CaO” relates to the concentration in weight of calcium containing compounds in the composition, wherein said compounds are expressed in the form of CaO.

[0103] X-ray fluorescence measurements to quantify the chemical composition of said SCM’s, were performed by use of a XRF S4 Pioneer (Bruker).Table 1 : Chemical composition of the materials used in the examples

[0104] Table 2 illustrates the mineralogical composition of the raw materials of Table 1. The mineralogical composition reflects herein the microstructure of the compositions, and was determined herein with X-ray diffraction, making use of a D8 Advance (Bruker). Further quantification was done by use of the Rietveld method.Table 2: Mineralogy of the materials used in the examples

[0105] Table 3 illustrates the particle size distribution (PSD) of the raw materials of Table 1, as well as of Limestone Filler (LSF), used in the examples. The particle size distribution was measured using a LS 13 320 Particle Size Analyzer (Beckman-Coulter).Table 3: Particle size values (D10, D50 and D90) for the used SCMs.

[0106] In the experiments below, a series of compositions or mixtures for mortars of concrete are presented. The compositions comprise a cementitious binder composition, water and sand for forming said mortar, grout or concrete. The compositions are prepared by mixing the dry components of the mixture, followed by adding under continuous mixing the components in liquid form, the latter relating mainly to the water component. Sand as used herein is CEN Normsand (DIN EN 196-1). The components in the experiments below are expressed in weight.

[0107] After adding all components, mixing is typically done for a period of a few minutes, the period used in the experiments herein is 3 minutes. In a subsequent step,the mixture is cast into beams and allowed to cure at room temperature with a strength profile being measured at different times after preparing the mixture (1 day, 2 days, 7 days, and 28 days). Compressive strength of the binder is measured on mortar level using molds produced in line with the EN 196-1 (2016) standard. A higher value for compressed strength is typically regarded as favorable and indicating an improved reactivity of the composition and durability of the final concrete or mortar.Example 2: binder compositions with GGBFS and AAC (E1 ; CE1-CE2)

[0108] Example 2 illustrates the use and performance of cementitious binder compositions having ground granulated blast furnace slag (GGBFS) and OPC (CEM I), wherein the former may be partially replaced by AAC or Limestone filler (LSF). These cementitious binder compositions are used in a mortar composition with water and sand quantities according to Table 4, following the method described above.

[0109] CE1 illustrates the case wherein only OPC and GGBFS are used, in equal quantities, as a binder in the mortar composition. 50.0 wt.% of OPC replacement by GGBFS can be considered as common practice in the industry and would lead to compositions, such as i.e. CEM lll / A (EN 197-1 (2011)). CE2 illustrates the partial replacement of GGBFS by LSF, whereas E1 illustrates the partial replacement of GGBFS by AAC, the latter according to the invention. The development of compressive strength as function of time is illustrated in Figure 1 for each of these compositions, wherein “D” refers to the number of days since casting the mold. It can be observed that for the partial (50%) replacement of GGBFS with AAC, the final value for the compressive strength is not negatively affected with regard to only GGBFS (CE1). When comparing the 7 days strength values of E1 and CE1 , it can even be observed that the incorporation of AAC results in an accelerated strength development. On the other hand, a clear reduction of the strength can be noted when replacing an equal amount of GGBFS by a filler, in casu LSF.Table 4: Mortar compositions including GGBFS.Example 3: binder compositions with Si-slag and AAC (E2; CE3-CE4)

[0110] Example 3 illustrates the use and performance of cementitious binder compositions containing silicon slag (Si-slag) and CEM I, wherein the former may be partially or completely replaced by AAC. These cementitious binder compositions are used in a mortar composition with water and sand quantities according to Table 5, following the method described above. CE3 illustrates the case wherein only OPC and Si-slag are used, in equal quantities, as a binder in the mortar composition, whereas CE4 illustrates the case wherein only OPC and AAC are used, in equal quantities. E2 illustrates the partial replacement of Si-slag by AAC according to the invention. The development of compressive strength as function of time is illustrated in Figure 2 for each of these compositions. It can be observed that for a binder composition having 50.0 wt.% of OPC, with 25.0 wt.% Si-slag and 25.0 wt.% AAC, a higher compressive strength is obtained after 28 days, with regard to the compositions containing only Si-slag or AAC as OPC replacement. The observations hint at the occurrence of a synergistic effect when combining Si-slag and AAC for the partial replacement of OPC.Table 5: Mortar compositions including Si-slag.Example 4: binder compositions with other SCM-compounds and AAC (E3-E5; CE5-CE7)

[0111] Example 4 illustrates the use and performance of cementitious binder compositions containing other types of SCM-compounds than used in the examples here above as well as OPC, wherein the former may also be partially replaced by AAC. The SCM-compounds used herein are non-ferrous slag, calcined clay and fly ash, wherein the ratio SCM-compound vs. OPC in the binder composition is subject to the nature of the SCM-compound as well as the intended final strength. The cementitious binder compositions are used in a mortar composition with water and sand quantities according to Table 6, following the method described above.

[0112] CE5-E3 illustrate the partial replacement of non-ferrous slag with AAC for a constant portion of OPC. Furthermore, CE6-E4 illustrate the partial replacement of calcined clay with AAC while keeping the OPC concentration constant. Finally, CE7-E5 illustrate the partial replacement of fly ash with AAC while keeping the OPC concentration constant.

[0113] The development of compressive strength as function of time is illustrated in Figure 3 for each of these compositions. It can be observed that partial replacement of each of these SCM-compounds with AAC, results in a better final value (after 28 days) for the compressive strength. Furthermore, observing the values for compressive strength after 7 days, it can also be concluded that the strength development is accelerated when replacing said SCM with AAC.Table 6: Mortar composition including various SCMs.Example 5: binder compositions and leaching (E2; CE8)

[0114] Example 5 relates to the occurrence of sulphate leaching for binder compositions. Table 7 shows binder compositions for the purpose of measuring and comparing the occurrence of sulphate leaching (DIN 38414-S4 (1984)), by comparing the effect of using AAC as a sole replacement of OPC and the combination of AAC with an SCM as OPC replacement. The binders have the same clinker content and a similar CO2 footprint. The leaching values are given in Table 8. It can be observed that the combination of a SCM with AAC has a much lower leaching behavior of SO4 compared to the case with only ‘Fine AAC’. In order to give a reference to these values as sulfates are part of OPC, the values for pure OPC are included as CE9. The combination of an SCM with AAC positively influences the incorporation of AAC as a component for a binder composition.Table 7: Mortar compositions for testing sulphate leachingTable 8: sulphate leaching for mortars compositions of Table 7

[0115] By “the weight ratio SiO2:CaO” is meant the ratio between the weight of silicon-containing compounds when expressed in the form of SiC>2 relative to the weight of the Si-Slag and the weight of calcium-containing compounds when expressed in the form of CaO.

[0116] By the expression ”a composition is XX wt. % amorphous” is meant that said composition has a fraction of XX percent of amorphous phase as determined the internal standard method.

[0117] When analyzing XRD patterns, especially those containing both crystalline and amorphous phases (like glass), the internal standard method is employed. The sample which includes both crystalline and amorphous components is mixed with a precisely known amount of a 100% crystalline standard material. This is the “internal standard.” Zincite (ZnO) is used as internal standard thanks to its 100% crystallinity, symmetric structure and chemically inert character. A content of 5.0 or 10.0 wt.% of zincite is generally added to the specimen. The diffraction pattern obtained will contain peaks from both the sample and the zincite. The refined phase quantities obtained through the Rietveld refinement method will then overestimate the crystalline phases. Knowing the true zincite content added, by difference, the amorphous phase can be evaluated.

[0118] A D50 value (a.k.a. a mass-median diameter value (D50)) of a composition is preferably determined with particle size distribution (PSD) of said composition as measured using a LS 13 320 Particle Size Analyzer (Beckman-Coulter).

[0119] Preferred embodiments of the present invention are also defined by the following clauses:1. A cementitious binder composition for a concrete, grout or mortar, said cementitious binder composition comprising or consisting of:(A) optionally at least 5.0 wt.%, preferably at least 10.0 wt.%, most preferably at least 15.0 wt.%, but lower than 70.0 wt.%, preferably lower than 60.0 wt.% of a Supplementary Cementitious Material (SCM), said Supplementary Cementitious Material (SCM) being at least 1.0 wt.%, preferably at least 2.0 wt.%, more preferably at least 5.0 wt.%, and most preferably at least 8.0 wt.% amorphous, in particular glassy, preferably wherein said Supplementary Cementitious Material (SCM) comprises:- at least 15.0 wt.%, preferably at least 20.0 wt.%, more preferably at least 25.0 wt.%, most preferably at least 30.0 wt.% but at most 70.0 wt.%, preferably at most 65.0 wt.%, most preferably at most 60.0 wt.% of silicon- containing compounds when expressed in the form of SiC>2, and at least 7.5 wt.%, preferably at least 10.0 wt.%, more preferably at least 12.5 wt.%, most preferably at least 15.0 wt.% but at most 40.0 wt.%, preferably at most 37.5 wt.%, more preferably at most 35.0 wt.%, even more preferably at most 32.5 wt.% most preferably at most 30.0 wt.% of aluminum-containing compounds when expressed in the form of AI2O3, with respect to the total weight of the Supplementary Cementitious Material (SCM); and(B) At least 0.5 wt.%, preferably at least 2.0 wt.%, more preferably at least 10.0 wt.%, most preferably at least 15.0 wt.%, but lower than 50.0 wt.%, preferably lower than 35.0 wt.% of a comminuted Autoclave Aerated Concrete, preferably said comminuted Autoclave Aerated Concrete comprising between 10.0 wt.% and 40.0 wt.%, preferably between 15.0 wt.% and 30.0 wt.% of calcium- containing compounds, when expressed in the form of CaO, and between 30.0 wt.% and 60.0 wt.%, preferably between 35.0 wt.% and 50.0 wt.% of silicon-containing compounds when expressed in the form of SiC>2, with respect to the total weight of the comminuted Autoclave Aerated Concrete, more preferably wherein said comminuted Autoclave Aerated Concrete has a D50 value of at most 30 pm, preferably at most 15 pm; and(C) At least 5.0 wt.%, preferably at least 10.0 wt.%, most preferably at least 15.0 wt.%, but less than 90.0 wt.%, preferably less than 75.0 wt.% of a cement; and(D) Optionally a flow improving agent; and(E) Optionally at least 2.0 wt.% but lower than 50.0 wt.% of a binding compound;preferably said binder composition having at least 5.0 wt.%, preferably at least 10.0 wt.%, most preferably at least 15.0 wt.%, but less than 90.0 wt.%, preferably less than 75.0 wt.% of calcium silicate mineral phases [SCaO.SiCh] and [2CaO.SiC>2].2. The cementitious binder composition for a concrete, grout or mortar according to clause 1 , wherein the Supplementary Cementitious Material (A) has a D50 value of at most 30 pm, preferably at most 15pm.3. The cementitious binder composition for a concrete, grout or mortar according to clause 1 or 2, wherein the Supplementary Cementitious Material (A) is selected from the list consisting of : pumices; ashes; zeolitized tuffs; diatomaceous earths; burned or calcined clays; burned shales; fly ashes; ironmaking slags including smelter slags and blast furnace slag, such as GGBFS; silica fumes; primary and secondary steel slags; non-ferrous slags, such as Si-slag; bottom ashes; waste glass; municipal waste incineration ashes; biomass combustion ashes, and combinations thereof.4. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein the cement is:- an Ordinary Portland cement (OPC), in particular Portland cement (OEM I) according to EN 197-1 (2011), or- a Blended cement, in particular selected from the group consisting of Portland composite cement (OEM II as EN 197-1 (2011)), blast furnace slag cement (OEM III as EN 197-1 (2011)), pozzolanic cement (OEM IV as EN 197-1 (2011)), slag-pozzolanic cement (OEM (LL,S) V as EN 197-1 (2011)), composite cement (such as OEM ll / C-M (LL,S) and OEM VI as EN 197-5 (2021)), cement with recycle building materials (OEM II and OEM VI as EN 197-6 (2023)), and combinations thereof, or- a combination of the Ordinary Portland cement and the Blended cement.5. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein the weight ratio of said Supplementary Cementitious Material (A) to said comminuted Autoclave Aerated Concrete (B), meaning (A):(B), is at least 1.0:4.0, preferably at least 1.0:2.0 and at most 4.0:1.0.6. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein the weight ratio of a combination of said Supplementary Cementitious Material (A) and said comminuted Autoclave AeratedConcrete (B) with regard to said cement (C), meaning ((A)+(B)):(C), is at least 1.0:19.0, preferably is at least 1.0:9.0, even more preferably is at least 1.0:4.0.7. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein the flow improving agent (D) is selected from the list comprising: a naphthalene-based superplasticizer; a lignosulfonate; a protein, such as casein; a naphthalene sulphonate; a melamine-based superplasticizer; a polycarboxylate ether (PCE) or polyacrylate ether (PAE) based superplasticizer, a salt or derivative thereof; and mixtures thereof.8. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein the binding compound (E) is selected from the list consisting of an ash, a clay, a calcined clay, a distinct metallurgical slag, a mine tailing, a quartz filler, bauxite residue, and mixtures thereof.9. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein the Supplementary Cementitious Material (A) and / or the cement (C) comprises CaCCh issued from a different source than the CaCCh from the comminuted Autoclave Aerated Concrete (B).10. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein said Supplementary Cementitious Material (A) is further at least 30.0 wt.%, preferably at least 40 wt.%, more preferably at least 50.0 wt.%, most preferably at least 60.0 wt.% amorphous, in particular glassy.11. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein the Supplementary Cementitious Material (A) comprises at least 15.0 wt.%, preferably at least 20.0 wt.%, most preferably at least 25.0 wt.% of calcium-containing compounds when expressed in the form of CaO, with respect to the total weight of the SCM and / or at most 40.0 wt.%, preferably at most 35.0 wt.%, most preferably at most 30.0 wt.%, in particular at most 25% of calcium-containing compounds when expressed in the form of CaO, with respect to the total weight of the Supplementary Cementitious Material (A).12. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein the Supplementary Cementitious Material (A)comprises an amount of aluminum-containing compounds when expressed in the form of AI2O3 and an amount of iron-containing compounds when expressed in the form of Fe2C>3, wherein the sum of both amounts forms at least 10.0 wt.%, preferably at least 12.5 wt.%, and most preferably at least 15.0 wt.% of the total weight of said Supplementary Cementitious Material (A).13. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein the Supplementary Cementitious Material (A) comprises at least 4.0 wt.%, and / or at least 5.0 wt.%, more preferably at least 6.0 wt.%, and most preferably at least 7.0 wt.% of manganese-containing compounds when expressed in the form of MnO, but less than 21.0 wt.%, preferably less than 15.0 wt.% with respect to the total weight of the Supplementary Cementitious Material (A).14. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein the Supplementary Cementitious Material (A) has a weight ratio of SiO2:CaO of at least 0.6, preferably at least 0.7, more preferably at least 0.8, even more preferably at least 0.9, most preferably at least 1.0, in particular at least 1.1 , more particularly at least 1.2.15. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein the comminuted Autoclave Aerated Concrete (B) comprises at least 15.0 wt.%, preferably at least 17.5 wt.%, most preferably at least 20.0 wt.% of calcium-containing compounds when expressed in the form of CaO, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B).16. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein the comminuted Autoclave Aerated Concrete (B) comprises at most 35.0 wt.%, preferably at most 32.5 wt.%, and most preferably at most 30.0 wt.% of calcium-containing compounds when expressed in the form of CaO, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B).17. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein the comminuted Autoclave Aerated Concrete (B) comprises at least 35.0 wt.%, preferably at least 37.5 wt.%, and most preferably at least 40.0 wt.% of silicon-containing compounds when expressed in the form of SiC>2, withrespect to the total weight of the comminuted Autoclave Aerated Concrete (B) and / or at most 55.0 wt.%, preferably at most 52.5 wt.%, and most preferably at most 50.0 wt.% of silicon-containing compounds when expressed in the form of SiC>2, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B).18. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein the comminuted Autoclave Aerated Concrete (B) comprises at least 0.5 wt.%, preferably at least 2.0 wt.%, and most preferably at least 3.0 wt.% of sulphur-containing compounds when expressed in the form of SO3, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B) and / or at most 10.0 wt.%, preferably at most 9.0 wt.%, and most preferably at most 8.0 wt.% of sulphur- containing compounds when expressed in the form of SO3, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B).19. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein the comminuted Autoclave Aerated Concrete (B) comprises a weight ratio of SiO2:CaO of at least 1.0: 1.0, preferably at least 1.2: 1.0, and most preferably at least 1.4: 1.0.20. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein the comminuted Autoclave Aerated Concrete (B) comprises at least one carbonate, wherein said Autoclave Aerated Concrete (B) contains at least 5.0 wt.%, more preferably at least 10.0 wt.% and most preferably at least 15.0 wt.% of the at least one carbonate, with regard to the total weight of the comminuted Autoclave Aerated Concrete (B), preferably the at least one carbonate being CaCCh.21. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein the comminuted Autoclave Aerated Concrete (B) comprises or consists of a powdery material, having a D50 value smaller than 30 pm, more preferably smaller than 25 pm, even more preferably smaller than 20pm, more preferably smaller than 15pm, and most preferably smaller than 10 pm and / or powdery material having a Dmax value which is smaller than 65 pm, preferably smaller than 60 pm, more preferably smaller than 55 pm, even more preferably smaller than 50 pm and most preferably smaller than 45 pm.22. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein the comminuted Autoclave Aerated Concrete (B) further comprises or consists of a fine Autoclave Aerated Concrete (B), wherein said fine Autoclave Aerated Concrete (B) has a D50 value smaller than 30 pm, more preferably smaller than 25 pm, even more preferably smaller than 20 pm, more preferably smaller than 15 pm, and most preferably smaller than 10 pm and / or has a Dmax value which is smaller than 65 pm, preferably smaller than 60 pm, more preferably smaller than 55 pm, even more preferably smaller than 50 pm and most preferably smaller than 45 pm.23. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein the Supplementary Cementitious Material (A) is different from the comminuted Autoclave Aerated Concrete (B).24. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein the comminuted Autoclave Aerated Concrete (B) is different from the cement (C).25. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous clauses, wherein the Cement (C) is different than the Supplementary Cementitious Material (A).26. A process for the manufacturing of a premix for a cementitious binder composition according to any one of clauses 1-25 comprising the steps of:- providing the Supplementary Cementitious Material (A);- providing the comminuted Autoclave Aerated concrete (B);- mixing the Supplementary Cementitious Material (A) with the comminuted Autoclave Aerated concrete (B) to form the premix.27. A process for the manufacturing of a cementitious binder composition according to any one of clauses 1-25, said process comprises the step of- optionally providing the cement (C);- optionally providing the premix obtained with the process of clause 26;- optionally providing one or more compounds selected from the group comprising: the flow improving agent (D) and the binding compound (E);- mixing the premix obtained with the process of clause 26 with the cement (C) and optionally the one or more compounds selected from the group comprising:the flow improving agent (D) and the binding compound (E), to form said cementitious binder composition.28. A mortar, grout or concrete composition comprising the cementitious binder composition according to any one of clauses 1 -25, and at least one of aggregate, sand, and water.29. A process for the manufacturing of a mortar, grout or concrete composition according to clause 28, wherein said process comprises the steps of:- providing a cementitious binder composition as defined in according to any one of clauses 1-25;- providing at least one of aggregate and sand;- mixing of said cementitious binder composition with of said aggregate and / or said sand, thereby forming a mixture;- adding of said water to said mixture.30. Use of a cementitious binder composition according to any one of clauses 1-25 for producing a mortar, grout or concrete composition as defined in clause 28.31. A cementitious binder precursor composition for a cementitious binder composition for a concrete, grout or mortar, said cementitious binder precursor composition comprising or consisting of:(A) At least 7.0 wt.% but lower than 85.0 wt.%, preferably lower than 70.0 wt.% of a Supplementary Cementitious Material (SCM), preferably said Supplementary Cementitious Material (SCM) being at least 1.0 wt.%, preferably at least 2.0 wt.%, more preferably at least 5.0 wt.%, and most preferably at least 8.0 wt.% amorphous, in particular glassy, preferably said Supplementary Cementitious Material (SCM) comprising at least 15.0 wt.%, preferably at least 20.0 wt.%, more preferably at least 25.0 wt.%, most preferably at least 30.0 wt.% but at most 70.0 wt.%, preferably at most 65.0 wt.%, most preferably at most 60.0 wt.% of silicon-containing compounds when expressed in the form of SiC>2, and at least 7.5 wt.%, preferably at least 10.0 wt.%, more preferably at least 12.5 wt.%, most preferably at least 15.0 wt.% but at most 40.0 wt.%, preferably at most 37.5 wt.%, more preferably at most 35.0 wt.%, even more preferably at most 32.5 wt.% most preferably at most 30.0 wt.% of aluminum-containing compounds when expressed in theform of AI2O3, with respect to the total weight of the Supplementary Cementitious Material (SCM);(B) At least 2.0 wt.% but lower than 70.0 wt.% of a comminuted Autoclave Aerated Concrete, preferably said comminuted Autoclave Aerated Concrete comprising between 10.0 wt.% and 40.0 wt.%, preferably between 15.0 wt.% and 30.0 wt.% of calcium-containing compounds, when expressed in the form of CaO, and between 30.0 wt.% and 60.0 wt.%, preferably between 35.0 wt.% and 50.0 wt.% of silicon-containing compounds when expressed in the form of SiC>2, with respect to the total weight of the comminuted Autoclave Aerated Concrete, more preferably said comminuted Autoclave Aerated Concrete having a D50 value of at most 30 pm, preferably at most 15 pm.32. The cementitious binder precursor composition according to clause 31 , wherein said Supplementary Cementitious Material (A) has a D50 value of at most 30 pm, preferably at most 15pm.33. The cementitious binder precursor composition according to any one of clauses 31 to 32, wherein said Supplementary Cementitious Material (A) is selected from the list consisting of : pumices; ashes; zeolitized tuffs; diatomaceous earths; burned or calcined clays; burned shales; fly ashes; ironmaking slags including smelter slags and blast furnace slags, such as GGBFS; silica fumes; primary and secondary steel slags; non-ferrous slag, such as Si-slag; bottom ashes; waste glass; municipal waste incineration ashes; biomass combustion ashes, and combinations thereof.34. The cementitious binder precursor composition according to any one of clauses 31 to 33, wherein the weight ratio of said Supplementary Cementitious Material (A) to said comminuted Autoclave Aerated Concrete (B), or (A):(B), is at least 1.0:4.0, preferably at least 1.0:2.0 and at most 4.0: 1.0.35. The cementitious binder precursor composition according to any one of clauses 31 to 34, wherein said Supplementary Cementitious Material (A) is further at least 30.0 wt.%, preferably at least 40.0 wt.%, more preferably at least 50.0 wt.%, most preferably at least 60.0 wt.% amorphous, in particular glassy.36. The cementitious binder precursor composition according to any one of clauses 31 to 35, wherein the Supplementary Cementitious Material (A) comprises CaCCh issued from a different source than the CaCCh from the comminuted Autoclave Aerated Concrete (B).37. The cementitious binder precursor composition according to any one of clauses 31 to 36, wherein the Supplementary Cementitious Material (A) comprises at least 15.0 wt.%, preferably at least 20.0 wt.%, most preferably at least 25.0 wt.% of calcium-containing compounds when expressed in the form of CaO, with respect to the total weight of the SCM and / or at most 40.0 wt.%, preferably at most 35.0 wt.%, more preferably at most 30.0 wt.%, in particular at most 25.0% of calcium-containing compounds when expressed in the form of CaO, with respect to the total weight of the Supplementary Cementitious Material (A).38. The cementitious binder precursor composition according to any one of clauses 31 to 37, wherein the Supplementary Cementitious Material (A) comprises an amount of aluminum-containing compounds when expressed in the form of AI2O3 and an amount of iron-containing compounds when expressed in the form of Fe2C>3, wherein the sum of both amounts forms at least 10.0 wt.%, preferably at least 12.5 wt.%, and most preferably at least 15.0 wt.% of the total weight of said Supplementary Cementitious Material (A).39. The cementitious binder precursor composition according to any one of clauses 31 to 38, wherein the Supplementary Cementitious Material (A) comprises at least 4.0 wt.%, preferably at least 5.0 wt.%, more preferably at least 6.0 wt.%, and most preferably at least 7.0 wt.% of manganese-containing compounds when expressed in the form of MnO, but less than 21.0 wt.%, preferably less than 15.0 wt.% with respect to the total weight of the Supplementary Cementitious Material (A).40. The cementitious binder precursor composition according to any one of clauses 31 to 39, wherein the Supplementary Cementitious Material (A) has a weight ratio of SiC>2:CaO of at least 0.6, preferably at least 0.7, more preferably at least 0.8, even more preferably at least 0.9, most preferably at least 1.0, in particular at least 1.1 , more particularly at least 1.2.41. The cementitious binder precursor composition according to any one of clauses 31 to 40, wherein the comminuted Autoclave Aerated Concrete (B) comprises at least 15.0 wt.%, preferably at least 17.5 wt.%, most preferably at least 20.0 wt.% of calcium-containing compounds when expressed in the form of CaO, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B).42. The cementitious binder precursor composition according to any one of clauses 31 to 41 , wherein the comminuted Autoclave Aerated Concrete (B) comprises at most 35.0 wt.%, preferably at most 32.5 wt.%, and most preferably at most 30.0 wt.% of calcium- containing compounds when expressed in the form of CaO, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B);43. The cementitious binder precursor composition according to any one of clauses 31 to 42, wherein the comminuted Autoclave Aerated Concrete (B) comprises at least 35.0 wt.%, preferably at least 37.5 wt.%, and most preferably at least 40.0 wt.% of silicon- containing compounds when expressed in the form of SiC>2, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B) and / or at most 55.0 wt.%, preferably at most 52.5 wt.%, and most preferably at most 50.0 wt.% of silicon-containing compounds when expressed in the form of SiC>2, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B).44. The cementitious binder precursor composition according to any one of clauses 31 to 43, wherein the comminuted Autoclave Aerated Concrete (B) comprises at least 0.5 wt.%, preferably at least 2.0 wt.%, and most preferably at least 3.0 wt.% of sulphur- containing compounds when expressed in the form of SO3, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B) and / or at most 10.0 wt.%, preferably at most 9.0 wt.%, and most preferably at most 8.0 wt.% of sulphur-containing compounds when expressed in the form of SO3, with respect to the total weight of the comminuted Autoclave Aerated Concrete (B).45. The cementitious binder precursor composition according to any one of clauses 31 to 44, wherein the comminuted Autoclave Aerated Concrete (B) comprises a weight ratio of SiC>2:CaO of at least 1.0: 1.0, preferably at least 1.2: 1.0, and most preferably at least 1.4:1.0.46. The cementitious binder precursor composition according to any one of clauses 31 to 45, wherein the comminuted Autoclave Aerated Concrete (B) comprises at least one carbonate, wherein said the comminuted Autoclave Aerated Concrete (B) contains at least 5.0 wt.%, more preferably at least 10.0 wt.% and most preferably at least 15.0 wt.%of the at least one carbonate, with regard to the total weight of the comminuted Autoclave Aerated Concrete (B), preferably the at least one carbonate being CaCCh.47. The cementitious binder precursor composition according to any one of clauses 31 to 46, wherein the comminuted Autoclave Aerated Concrete (B) comprises or consists of a powdery material, having a D50 value smaller than 30 pm, more preferably smaller than 25 pm, even more preferably smaller than 20pm, more preferably smaller than 15pm, and most preferably smaller than 10 pm and / or powdery material having a Dmax value which is smaller than 65 pm, preferably smaller than 60 pm, more preferably smaller than 55 pm, even more preferably smaller than 50 pm and most preferably smaller than 45 pm.48. The cementitious binder precursor composition according to any one of clauses 31 to 47, wherein the comminuted Autoclave Aerated Concrete (B) comprises or consists of a fine Autoclave Aerated Concrete (B), wherein said fine Autoclave Aerated Concrete (B) has a D50 value smaller than 30 pm, more preferably smaller than 25 pm, even more preferably smaller than 20 pm, more preferably smaller than 15 pm, and most preferably smaller than 10 pm and / or has a Dmax value which is smaller than 65 pm, preferably smaller than 60 pm, more preferably smaller than 55 pm, even more preferably smaller than 50 pm and most preferably smaller than 45 pm.49. The cementitious binder precursor composition according to any one of clauses 31 to 48, wherein the Supplementary Cementitious Material (A) is different from the comminuted Autoclave Aerated Concrete (B).50. A process for the manufacturing of a cementitious binder precursor composition according to any one of clauses 31 to 49, comprising the steps of:- providing the Supplementary Cementitious Material (A);- providing comminuted Autoclave Aerated Concrete (B);- mixing the Supplementary Cementitious Material (A), with the comminuted Autoclave Aerated Concrete (B) to form said cementitious binder precursor composition.

Claims

CLAIMS1. A cementitious binder composition for a concrete, grout or mortar, said cementitious binder composition comprising:(A) at least 5.0 wt.%, preferably at least 10.0 wt.%, most preferably at least 15.0 wt.%, but lower than 70.0 wt.%, preferably lower than 60.0 wt.% of a Supplementary Cementitious Material, said Supplementary Cementitious Material (SCM) being at least 1.0 wt.%, preferably at least 2.0 wt.%, more preferably at least 5.0 wt.%, and most preferably at least 8.0 wt.% amorphous, wherein said Supplementary Cementitious Material comprises:- at least 15.0 wt.% , preferably at least 20.0 wt.%, more preferably at least 25.0 wt.%, most preferably at least 30.0 wt.% but at most 70.0 wt.%, preferably at most 65.0 wt.%, most preferably at most 60.0 wt.% of silicon- containing compounds when expressed in the form of SiC>2 with respect to the total weight of the Supplementary Cementitious Material, and-at least 7.5 wt.%, preferably at least 10.0 wt.%, more preferably at least 12.5 wt.%, most preferably at least 15.0 wt.% but at most 40.0 wt.%, preferably at most 37.5 wt.%, more preferably at most 35.0 wt.%, even more preferably at most 32.5 wt.%, most preferably at most 30.0 wt.% of aluminum-containing compounds when expressed in the form of AI2O3, with respect to the total weight of the Supplementary Cementitious Material (SCM), wherein the Supplementary Cementitious Material has a D50 value of at most 30 pm, preferably at most 15pm; and(B) at least 0.5 wt.%, preferably at least 2.0 wt.%, more preferably at least 5.0 wt.%, most preferably at least 10.0 wt.%, but lower than 50.0 wt.%, preferably lower than 35.0 wt.% of a comminuted Autoclave Aerated Concrete, wherein said comminuted Autoclave Aerated Concrete comprises:- between 10.0 wt.% and 40.0 wt.%, preferably between 15.0 wt.% and 30.0 wt.% of calcium-containing compounds, when expressed in the form of CaO, with respect to the total weight of the comminuted Autoclave Aerated Concrete, and-between 30.0 wt.% and 60.0 wt.%, preferably between 35.0 wt.% and 50.0 wt.% of silicon-containing compounds when expressed in the form of SiC>2, with respect to the total weight of the comminuted Autoclave Aerated Concrete,wherein said comminuted Autoclave Aerated Concrete has a D50 value of at most 30 pm, preferably at most 15 pm; and(C) at least 5.0 wt.%, preferably at least 10.0 wt.%, most preferably at least 15.0 wt.%, but less than 90.0 wt.%, preferably less than 75.0 wt.% of a cement; wherein said cementitious binder composition has at least 5.0 wt.%, preferably at least 10.0 wt.%, most preferably at least 15.0 wt.%, but less than 90.0 wt.%, preferably less than 75.0 wt.% of calcium silicate mineral phases [SCaO.SiCh] and [2CaO.SiC>2].

2. The cementitious binder composition for a concrete, grout or mortar according to claim 1 , wherein the Supplementary Cementitious Material (A) is selected from the list consisting of : pumices, ashes, zeolitized tuffs, diatomaceous earths, a burned or calcined clays, burned shales, fly ashes, ironmaking slags including smelter slags and blast furnace slags, such as GGBFS, silica fumes, primary and secondary steel slags, non-ferrous slags, such as Si-slag, bottom ashes, waste glass, municipal waste incineration ashes, and combinations thereof.

3. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous claims, wherein the cement is:- an Ordinary Portland cement (OPC), in particular Portland cement (OEM I) according to EN 197-1 (2011), or- a Blended cement, in particular selected from the group consisting of Portland composite cement (OEM II as EN 197-1 (2011)), blast furnace slag cement (OEM III as EN 197-1 (2011)), pozzolanic cement (OEM IV as EN 197-1 (2011)), slag-pozzolanic cement (OEM (LL,S) V as EN 197-1 (2011)), composite cement (such as OEM ll / C-M (LL,S) and OEM VI as EN 197-5 (2021)), cement with recycle building materials (OEM II and OEM VI as EN 197-6 (2023)), and combinations thereof, or- a combination of the Ordinary Portland cement and the Blended cement.

4. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous claims, wherein the Supplementary Cementitious Material (A) is different from the comminuted Autoclave Aerated Concrete (B).

5. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous claims, wherein the weight ratio of the Supplementary CementitiousMaterial (A) to the comminuted Autoclave Aerated Concrete (B), meaning (A):(B), is at least 1.0:4.0, preferably at least 1.0:2.0 and at most 4.0: 1.0.

6. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous claims, wherein the weight ratio of a combination of said Supplementary Cementitious Material (A) and said comminuted Autoclave Aerated Concrete (B) with regard to said cement (C), meaning ((A)+(B)):(C), is at least 1.0:19.0, preferably is at least 1.0:9.0, even more preferably is at least 1.0:4.0.

7. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous claims; wherein said cementitious binder composition further comprises at least 2.0 wt.% with reference to the total weight of said binder composition but lower than 50.0 wt.% with reference to the total weight of said binder composition of a binding compound, said binding compound being selected from the list consisting of an ash, a clay, a calcined clay, a distinct metallurgical slag, a mine tailing, a quartz filler, bauxite residue, and mixtures thereof.

8. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous claims, further comprising a flow improving agent (D), wherein the flow improving agent is selected from the list comprising: a naphthalene-based superplasticizer; a lignosulfonate; a protein, such as casein; a naphthalene sulphonate; a melamine-based superplasticizer; a polycarboxylate ether (PCE) or polyacrylate ether (PAE) based superplasticizer, a salt or derivative thereof; and mixtures thereof.

9. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous claims, wherein the Supplementary Cementitious Material (A) is further at least 30.0 wt.%, preferably at least 40.0 wt.%, more preferably at least 50.0 wt.%, and most preferably at least 60.0 wt.% amorphous.

10. The cementitious binder composition for a concrete, grout or mortar according to any one of the previous claims, wherein the Supplementary Cementitious Material (A) is different from the cement (C).

11. A process for the manufacturing of a premix for a cementitious binder composition according to any one of claims 1-10 comprising the steps of:- providing the Supplementary Cementitious Material (A);- providing the comminuted Autoclave Aerated concrete (B);- mixing the Supplementary Cementitious Material (A) with the comminuted Autoclave Aerated concrete (B) to form the premix.

12. A process for the manufacturing of a cementitious binder composition according to any one of claims 1-10, said process comprises the step of mixing the premix obtained with the process of claim 11 with the cement (C), to form said cementitious binder composition.

13. A mortar, grout or concrete composition comprising the cementitious binder composition according to any one of claims 1-10, and at least one of aggregate, sand and / or water.

14. A process for the manufacturing of a mortar, grout or concrete composition according to claim 13, wherein said process comprises the steps of:- providing a cementitious binder composition according to any one of claims 1- 10;- providing at least one of aggregate and / or sand;- mixing of said cementitious binder composition with of said aggregate and / or said sand, thereby forming a mixture;- adding of said water to said mixture.

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