Admixture for controlling heat flow from a mineral binder composition, mineral binder composition, and process for producing same - Patents.com

Abstract

The present invention relates to an admixture for mineral binder compositions, in particular for concrete, said admixture comprising or consisting of a) at least one rate modifier selected from esters of hydroxycarboxylic acids, in particular citrate, tartarate, lactate, gluconate, malate, glycolate and / or mandelic acid esters, b) optionally an accelerator for the hydration of cement, and c) optionally water. The admixture of the present invention reduces the maximum heat flow from the mineral binder composition, in particular concrete, without excessively retarding its setting and / or hardening.

Description

[Technical field]

[0001] The present invention relates to the field of admixtures for mineral binder compositions, in particular for concrete, which reduce the maximum heat flow from the mineral binder composition, in particular concrete, without excessively retarding its setting and / or hardening. [Background technology]

[0002] It is a well-known phenomenon that cementitious materials generate and release heat when they hydrate. In particular, the hydration reaction of cement is exothermic, and a significant amount of energy, often called the heat of hydration, is released during the hydration of cement. This heat of hydration can be problematic, especially during the production of mass concrete.

[0003] Mass concrete refers to very thick structures of concrete, typically more than 80 cm thick. Such structures are often large in volume, and generally require the placement of a large amount of concrete in a short time to produce such structures. During the installation of mass concrete, a typical phenomenon is a large temperature difference between the inner and outer layers of concrete during setting and hardening. This temperature difference is due to the transfer and dissipation of heat of hydration from the inner layer of concrete through the outer layer and surface of concrete to the surroundings. Also, the core temperature of concrete can be very high, such as above 60°C or even above 80°C, which can lead to the formation of metastable hydrate phases. As a result, mass concrete has an increased risk of cracking, and the strength gain is less predictable and may even be lower than expected. Cracked mass concrete is less durable, and in some cases the cracking may even lead to structural failure.

[0004] Current solutions to address this problem include the use of special cements with low heat generation, cooling of aggregates, placing concrete in several sub-layers, curing with insulation, active cooling, and designing joints and sections to promote heat release. All of these solutions require additional steps that can be difficult to achieve on-site and significantly increase the complexity and cost of a particular project.

[0005] Retarders for the hydration of cementitious materials are known. However, such retarders typically either inhibit the hydration reaction, at least for a while, or slow down the hydration reaction. Typically, the inhibition does not balance the heat release, and when hydration finally begins, all of the heat of hydration is released. Slowing the hydration reaction balances the release of the heat of hydration over a longer period of time, but also increases the time to reach the desired degree of hardening, and often the desired strength, which can slow down the overall construction process. Summary of the Invention [Problem to be solved by the invention]

[0006] What is needed is a kinetic regulator for cementitious materials that can control or balance the heat release over the setting time. Ideally, such a kinetic regulator would not significantly inhibit the onset of cement hydration. In addition, such a kinetic regulator would not excessively prolong the setting of the cementitious material. Such a kinetic regulator would also be very useful to avoid temperature rises in the center of thick cementitious materials, such as mass concrete, and / or to avoid temperature differences between the inner and outer layers of thick cementitious materials, such as mass concrete. [Means for solving the problem]

[0007] It is an object of the present invention to provide an admixture for mineral binder compositions, particularly concrete, which is capable of controlling or balancing heat release over the setting time. Preferably, such an admixture will prolong the onset of cement hydration only to the extent that is practically acceptable. More preferably, such an admixture will not excessively prolong the setting of the cementitious material. It is a further object of the present invention to provide a mineral binder composition, particularly concrete, comprising such an admixture. Yet another object of the present invention is to provide a process for producing a cementitious material, particularly concrete, with controlled or balanced heat release over the setting time.

[0008] Surprisingly, this object could be solved by the admixture, the mineral binder composition and the process for producing the mineral binder composition according to the independent claims.

[0009] It has been found that rate modifiers selected from esters of hydroxycarboxylic acids, in particular citrate, tartarate, lactate, gluconate, malate, glycolate and / or mandelic acid esters, can control or balance the heat release over the hardening time of a mineral binder composition, in particular concrete, such that, for example, the peak or maximum heat flow from a cementitious composition comprising said rate modifier can be reduced by 10 to 90% compared to the same cementitious composition without said rate modifier.

[0010] For example, it has also been found that the core temperature of concrete measured after casting containing the rate modifier of the present invention is reduced by up to 40% compared to the same cast concrete not containing the aforementioned rate modifier.

[0011] Advantageous embodiments of the invention are the subject matter of the dependent claims.

[0012] Methods of carrying out the invention In this context, the term "comprising" refers to a composition having at least the recited components, and may additionally have any further components. Thus, the term "comprising" does not mean that the composition is limited to the recited components. On the other hand, the term "consisting of" means that the composition is limited to only the recited components and no more essential components. A composition consisting of the recited components may only contain other components that are completely unnecessary for the function of the aforementioned composition.

[0013] In a first aspect, the present invention relates to an admixture for a mineral binder composition, said admixture comprising: a) at least one rate modifier selected from esters of hydroxycarboxylic acids; b) optionally an accelerator for the hydration of cement; c) optionally water; It comprises or consists of:

[0014] Hydroxycarboxylic acids in the present context are organic molecules that contain at least one carboxylic acid group and at least one hydroxy group. Preferred esters of hydroxycarboxylic acids are selected from citrate, tartrate, lactate, gluconate, malate, glycolate and / or mandelate.

[0015] A mineral binder composition in the present context is a composition comprising at least one mineral binder, or may consist of at least one mineral binder.

[0016] In this context, a mineral binder is a) capable of reacting with water in a hydraulic reaction to form a hydrate phase, or b) capable of reacting with atmospheric gases, especially carbon dioxide, to form a hard solid phase, or c) It is a binder that can form a hard solid phase upon drying.

[0017] Preferably, the mineral binder is selected from cement, lime, magnesia, alumina, latent hydraulic binders and / or pozzolans, particularly preferably from cement. Preferably, the mineral binder in this context is a hydraulic binder.

[0018] The cement may in particular be Portland cement of type CEM I, CEM II, CEM III, CEM IV and CEM V as described in standard EN 197-1, Portland cement of type CEM VI as described in standard DIN EN 197-5, calcium aluminate cement as described in standard EN 14647 and / or calcium sulfoaluminate cement. Cements according to other standards are likewise covered, for example Portland cement according to standard ASTM C140-05 or cement according to Chinese, Japanese, Indian or other standards. The term "lime" is meant to cover natural hydraulic lime, blended lime, hydraulic lime and air lime as described in standard EN 459-1:2015. The term "alumina" refers to aluminum oxide, aluminum hydroxide, and / or aluminum oxyhydroxide such as gibbsite and boehmite, calcined or flash calcined alumina, alumina obtained from the Bayer process, hydrated aluminas such as amorphous mesophase alumina and rho phase alumina. The pozzolans and latent hydraulic materials are preferably selected from the group consisting of slag, clay, calcined clay, especially metakaolin, kiln dust, microsilica, fly ash, pyrogenic silica, precipitated silica, silica fume, zeolites, rice husk ash, calcined oil shale, and natural pozzolans such as pumice, trass, and finely ground limestone.

[0019] According to an embodiment, the at least one mineral binder comprises or essentially consists of any of the above mentioned types of Portland cement. In particular, the mineral binder comprises at least 5% by weight, preferably at least 20% by weight, more preferably at least 35% by weight, even more preferably at least 65% by weight, in particular at least 80% by weight, in particular at least 95% by weight of Ordinary Portland Cement (OPC).

[0020] Calcium sulfate (CaSO4) may be present in the mineral binder, for example in the form of gypsum, for example as part of cement. However, the mineral binder does not have to consist of calcium sulfate.

[0021] Preferably, the mineral binder composition of the present invention comprises at least 10% by weight, preferably at least 25% by weight, more preferably at least 33% by weight, even more preferably at least 66% by weight, even more preferably at least 80% by weight, particularly at least 90% by weight, in particular at least 99% by weight, of mineral binder, based on the total dry weight of the mineral binder composition.

[0022] The mineral binder composition may further comprise aggregates, further additives, and / or water. The aggregates and further additives are as described below.

[0023] According to an embodiment of the invention, the mineral binder composition is concrete or mortar or cement, in particular concrete. According to a preferred embodiment, the mineral binder composition is concrete comprising Portland cement of type CEM I, CEM II, CEM III, CEM IV or CEM V as specified in standard EN197-1, or Portland cement of type CEM VI as specified in standard DIN EN197-5, or Portland cement according to standard ASTM C140-05.

[0024] The rate regulators are selected from esters of hydroxycarboxylic acids. Particularly preferably, at least one rate regulator is selected from citrate, tartrate, lactate, gluconate, malate, glycolate and / or mandelate.

[0025] According to an embodiment, the rate regulator is a citrate ester. In particular, the rate regulator is an ester of citric acid with a polyhydric alcohol. More preferred is a mixed ester of citric acid and a fatty acid with a polyhydric alcohol.

[0026] Citric acid in this context is meant to also include isocitrate.

[0027] According to an embodiment, the rate modifier has the following general structure (I): [ka] where each R is, independently of the others, H or a branched or unbranched C2-C30 alkyl chain or a branched or unbranched C3-C30 alkenyl chain, which alkenyl chain may contain 1-6 double bonds, or a cyclohexyl group, or an aromatic group having 5-10 C atoms, with the proviso that at least one of R is not H.

[0028] It has been found that rate regulators having at least one hydrophobic moiety R of general structure (I) are particularly suitable in the context of the present invention.Suitable rate regulators of general structure (I) are monobutyl citrate, dibutyl citrate, tributyl citrate, monopentyl citrate, dipentyl citrate, tripentyl citrate, monohexyl citrate, dihexyl citrate, trihexyl citrate, monooleyl citrate, dioleyl citrate, trioleyl citrate, monostearyl citrate, distearyl citrate, tristearyl citrate, monolauryl citrate, dilauryl citrate, trilauryl citrate, monoprenyl citrate, diprenyl citrate, triprenyl citrate, monocyclohexyl citrate, dicyclohexyl citrate, tricyclohexyl citrate, monophenyl citrate, diphenyl citrate, and triphenyl citrate.

[0029] According to a further embodiment, the rate modifier is an ester of citric acid and a polyhydric alcohol. Such esters have the following general structure (II): [ka] wherein q is an integer from 0 to 4, preferably 1 or 2; R' are, independently of each other, H, or C(O)-R'''', or a moiety of general structure (III), with the proviso that at least one of R' is a moiety of general structure (III); R'''' is an unbranched C2-C30 alkyl chain or an unbranched C2-C30 alkenyl chain, which alkenyl chain may contain 1-6 double bonds; and general structure (III) is [ka] wherein each M is, independently of the other, H or an alkali metal or alkaline earth metal ion.

[0030] Suitable rate modifiers of general structure (II) are esters of citric acid with ethylene glycol, glycerol or erythritol. Such esters may be mono-, di- or triesters of citric acid. Such esters may be monomeric, oligomeric or polymeric.

[0031] In the present specification, the ester of citric acid and polyhydric alcohol can include additional ester groups formed with acids other than citric acid. Such acids are, in particular, acetic acid, propionic acid, and fatty acids. Accordingly, suitable rate regulators of general structure (II) also include the coesters of ethylene glycol, glycerol, or erythritol with citric acid and at least one of acetic acid, propionic acid, and fatty acids.

[0032] According to a particularly preferred embodiment, the rate regulator is selected from mono- and / or diglycerides of citric acid, which have the chemical structure of the following general formula (IV): Thus, according to a preferred embodiment, the rate regulator of the present invention has the general structure (IV): [ka] (In the formula, each R″ is, independently of the other, H or C(O)—R″″, provided that at least one R″ is not H; R'''' is an unbranched C2-C30 alkyl chain or an unbranched C2-C30 alkenyl chain, the alkenyl chain may contain 1-6 double bonds; Each R''' is, independently of the other, OM, where M is H or an alkali metal or alkaline earth metal ion, or is a moiety of the general structure (V): [ka] Each R″ is, independently of the other, H or C(O)—R″″, where R″″ is an unbranched C2-C30 alkyl chain or an unbranched C2-C30 alkenyl chain, the alkenyl chain may contain 1-6 double bonds.

[0033] The rate regulator of the present invention may be a monoglyceride of citric acid or a mixture of different monoglycerides of citric acid. The rate regulator of the present invention may be a diglyceride of citric acid or a mixture of different diglycerides of citric acid. The rate regulator of the present invention may also be a mixture of one or more monoglycerides and one or more diglycerides of citric acid. Preferably, the rate regulator of the present invention is a mixture of monoglycerides and diglycerides of citric acid.

[0034] Such mono- and / or diglycerides of citric acid are also known as Citrems. They are commercially available and commonly used in the food industry.

[0035] The moiety C(O)-R"" in general structures (IV) and (V) above is preferably derived from a fatty acid. Preferred fatty acids present as esters in general structures (IV) and (V) are caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, linoelaidic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, and docosahexanoic acid.

[0036] According to an embodiment, the rate regulator is a tartaric acid ester. In particular, the rate regulator is an ester of tartaric acid with a polyhydric alcohol. More preferred is a mixed ester of tartaric acid and a fatty acid with a polyhydric alcohol.

[0037] According to an embodiment, the rate modifier has the following general structure (VI): [ka] where each R is, independently of the others, H or a branched or unbranched C2-C30 alkyl chain or a branched or unbranched C3-C30 alkenyl chain, which alkenyl chain may contain 1-6 double bonds, or a cyclohexyl group, or an aromatic group having 5-10 C atoms, with the proviso that at least one of R is not H.

[0038] It has been found that rate regulators having at least one hydrophobic moiety R of general structure (VI) are particularly suitable in the context of the present invention.Suitable rate regulators of general structure (VI) are monobutyl tartrate, dibutyl tartrate, monopentyl tartrate, dipentyl tartrate, monohexyl tartrate, dihexyl tartrate, monooleyl tartrate, dioleyl tartrate, monostearyl tartrate, distearyl tartrate, monolauryl tartrate, dilauryl tartrate, monoprenyl tartrate, diprenyl tartrate, monocyclohexyl tartrate, dicyclohexyl tartrate, monophenyl tartrate, diphenyl tartrate.

[0039] In a further embodiment, the rate modifier is an ester of tartaric acid and a polyhydric alcohol. Such esters have the following general structure (VII): [ka] wherein q is an integer from 0 to 4, preferably 1 or 2; R' are, independently of each other, H, or C(O)-R'''', or a moiety of general structure (VIII), with the proviso that at least one of R' is a moiety of general structure (VIII); R'''' is an unbranched C2-C30 alkyl chain or an unbranched C2-C30 alkenyl chain, which alkenyl chain may contain 1-6 double bonds; general structure (VIII) is [ka] wherein each M is, independently of the other, H, or an alkali metal, or an alkaline earth metal ion.

[0040] Suitable rate modifiers of general structure (VII) are esters of tartaric acid with ethylene glycol, glycerol, or erythritol. Such esters may be monoesters or diesters of tartaric acid. Such esters may be monomeric, oligomeric, or polymeric.

[0041] In this context, the ester of tartaric acid and polyhydric alcohols can contain additional ester groups formed with acids other than tartaric acid. Such acids are, in particular, acetic acid, propionic acid, and fatty acids. Accordingly, suitable rate regulators of general structure (VII) also include coesters of ethylene glycol, glycerol, or erythritol with tartaric acid and at least one of acetic acid, propionic acid, and fatty acids.

[0042] According to a particularly preferred embodiment, the rate regulator is selected from mono- and / or diglycerides of tartaric acid, which have the chemical structure of the following general formula (IX): Thus, according to a preferred embodiment, the rate regulator of the present invention has the general structure (IX): [ka] (In the formula, each R″ is, independently of the other, H or C(O)—R″″, provided that at least one R″ is not H; R'''' is an unbranched C2-C30 alkyl chain or an unbranched C2-C30 alkenyl chain, the alkenyl chain may contain 1-6 double bonds; Each R''' is, independently of the other, OM, where M is H or an alkali metal or alkaline earth metal ion, or is a moiety of the general structure (X): [ka] Each R″ is, independently of the other, H or C(O)—R″″, where R″″ is an unbranched C2-C30 alkyl chain or an unbranched C2-C30 alkenyl chain, the alkenyl chain may contain 1-6 double bonds.

[0043] The rate regulator of the present invention may be a monoglyceride of tartaric acid or a mixture of different monoglycerides of tartaric acid. The rate regulator of the present invention may be a diglyceride of tartaric acid or a mixture of different diglycerides of tartaric acid. The rate regulator of the present invention may also be a mixture of one or more monoglycerides of tartaric acid and one or more diglycerides of tartaric acid. Preferably, the rate regulator of the present invention is a mixture of mono- and diglycerides of tartaric acid.

[0044] The moiety C(O)-R"" in the above general structures (IX) and (X) is preferably derived from a fatty acid. Preferred fatty acids present as esters in general structures (IX) and (X) are caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, wasenic acid, linoleic acid, linoelaidic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, and docosahexanoic acid.

[0045] Examples of preferred rate moderators are the diacetylated mono- and diglycerides of tartaric acid.

[0046] According to an embodiment, the rate regulator is a lactic acid ester. In particular, the rate regulator is an ester of lactic acid with a polyhydric alcohol. More preferably, the rate regulator is a mixed ester of lactic acid and a fatty acid with a polyhydric alcohol.

[0047] According to an embodiment, the rate modifier has the following general structure (XI): [ka] where R is a branched or unbranched C2-C30 alkyl chain or a branched or unbranched C3-C30 alkenyl chain, which may contain 1-6 double bonds, or a cyclohexyl group, or an aromatic group having 5-10 C atoms.

[0048] Suitable rate modifiers of general structure (XI) are butyl lactate, pentyl lactate, hexyl lactate, oleyl lactate, stearyl lactate, lauryl lactate, prenyl lactate, cyclohexyl lactate, phenyl lactate.

[0049] According to a further embodiment, the rate modifier is an ester of lactic acid and a polyhydric alcohol. Such esters have the following general structure (XII): [ka] wherein q is an integer from 0 to 4, preferably 1 or 2; R' are, independently of each other, H, or C(O)-R'''', or a moiety of general structure (XIII), with the proviso that at least one of R' is a moiety of general structure (XIII); R'''' is an unbranched C2-C30 alkyl chain or an unbranched C2-C30 alkenyl chain, which alkenyl chain may contain 1-6 double bonds; general structure (XIII) is [ka] )

[0050] Suitable rate modifiers of general structure (XII) are esters of lactic acid with ethylene glycol, glycerol, or erythritol.

[0051] In the present specification, the ester of lactic acid and polyhydric alcohol can contain additional ester groups formed with acids other than lactic acid. Such acids are, in particular, acetic acid, propionic acid, and fatty acids. Accordingly, suitable rate modifiers of general structure (XII) also include coesters of ethylene glycol, glycerol, or erythritol with lactic acid and at least one of acetic acid, propionic acid, and fatty acids.

[0052] According to a particularly preferred embodiment, the rate regulator is selected from monoglycerides of lactic acid, which have the chemical structure of the following general formula (XIV): Thus, according to a preferred embodiment, the rate regulator of the present invention has the general structure (XIV): [ka] (In the formula, each R″ is, independently of the other, H or C(O)—R″″, provided that at least one R″ is not H; R'''' is an unbranched C2 to C30 alkyl chain or an unbranched C2 to C30 alkenyl chain, the alkenyl chain may contain 1 to 6 double bonds.

[0053] The rate regulator of the present invention can be a monoglyceride of lactic acid or a mixture of different monoglycerides of lactic acid.

[0054] The moiety C(O)-R"" in general structure (XIV) above is preferably derived from a fatty acid. Preferred fatty acids present as esters in general structure (XIV) are caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, linoelaidic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, and docosahexanoic acid.

[0055] According to an embodiment, the rate regulator is a gluconic acid ester. In particular, the rate regulator is an ester of gluconic acid with a polyhydric alcohol. More preferred is a mixed ester of gluconic acid and a fatty acid with a polyhydric alcohol.

[0056] According to an embodiment, the rate modifier has the following general structure (XV): [ka] where R is a branched or unbranched C2-C30 alkyl chain or a branched or unbranched C3-C30 alkenyl chain, the alkenyl chain may contain 1-6 double bonds, or a cyclohexyl group, or an aromatic group having 5-10 C atoms.

[0057] Suitable rate modifiers of general structure (XV) are butyl gluconate, pentyl gluconate, hexyl gluconate, oleyl gluconate, stearyl gluconate, lauryl gluconate, prenyl gluconate, cyclohexyl gluconate, phenyl gluconate.

[0058] According to a further embodiment, the rate modifier is an ester of gluconic acid and a polyhydric alcohol. Such esters have the following general structure (XVI): [ka] wherein q is an integer from 0 to 4, preferably 1 or 2; R' are, independently of each other, H, or C(O)-R"", or a moiety of general structure (XVII), with the proviso that at least one of R' is a moiety of general structure (XVII), and R"" is an unbranched C2-C30 alkyl chain or an unbranched C2-C30 alkenyl chain, which alkenyl chain may contain 1-6 double bonds; general structure (XVII) is [ka] )

[0059] Suitable rate modifiers of general structure (XVI) are esters of gluconic acid with ethylene glycol, glycerol, or erythritol.

[0060] In the present context, the ester of gluconic acid with a polyhydric alcohol may contain additional ester groups formed with acids other than gluconic acid. Such acids are, in particular, acetic acid, propionic acid, and fatty acids. Accordingly, suitable rate regulators of general structure (XVI) also include coesters of ethylene glycol, glycerol, or erythritol with gluconic acid and at least one of acetic acid, propionic acid, and fatty acids.

[0061] According to a particularly preferred embodiment, the rate regulator is selected from monoglycerides of gluconic acid, which have the chemical structure of the following general formula (XVIII): Thus, according to a preferred embodiment, the rate regulator of the present invention has the general structure (XVIII): [ka] wherein each R″ is, independently of the other, H or C(O)—R″″, with the proviso that at least one R″ is not H, and R″″ is an unbranched C2-C30 alkyl chain or an unbranched C2-C30 alkenyl chain, which alkenyl chain may contain 1-6 double bonds.

[0062] The rate regulator of the present invention can be a monoglyceride of gluconic acid or a mixture of different monoglycerides of gluconic acid.

[0063] The moiety C(O)-R"" in general structure (XVIII) above is preferably derived from a fatty acid. Preferred fatty acids present as esters of general structure (XVIII) are caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, wasenic acid, linoleic acid, linoelaidic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, and docosahexanoic acid.

[0064] According to an embodiment, the rate regulator is a malic acid ester. In particular, the rate regulator is an ester of malic acid with a polyhydric alcohol. More preferably, the rate regulator is a mixed ester of malic acid and a fatty acid with a polyhydric alcohol.

[0065] According to an embodiment, the rate modifier has the following general structure (IXX): [ka] where each R is, independently of the others, H, or a branched or unbranched C2-C30 alkyl chain, or a branched or unbranched C3-C30 alkenyl chain, which alkenyl chain may contain 1-6 double bonds, or a cyclohexyl group, or an aromatic group having 5-10 C atoms, with the proviso that at least one of R is not H.

[0066] It has been found that rate regulators of general structure (IXX) having at least one hydrophobic moiety R are particularly suitable in the context of the present invention.Suitable rate regulators of general structure (IXX) are monobutyl maleate, dibutyl maleate, monopentyl maleate, dipentyl maleate, monohexyl maleate, dihexyl maleate, monooleyl maleate, dioleyl maleate, monostearyl maleate, distearyl maleate, monolauryl maleate, dilauryl maleate, monoprenyl maleate, diprenyl maleate, monocyclohexyl maleate, dicyclohexyl maleate, monophenyl maleate, diphenyl maleate.

[0067] In a further embodiment, the rate modifier is an ester of malic acid and a polyhydric alcohol. Such esters have the following general structure (XX): [ka] wherein q is an integer from 0 to 4, preferably 1 or 2; R' are, independently of each other, H, or C(O)-R'''', or a moiety of general structure (XXIa) or (XXIb), with the proviso that at least one of R' is a moiety of general structure (XXIa) or (XXIb); R'''' is an unbranched C2-C30 alkyl chain or an unbranched C2-C30 alkenyl chain, which alkenyl chain may contain 1-6 double bonds; general structures (XXIa) and (XXIb) are [ka] where each M is, independently of the other, H, an alkali metal, or an alkaline earth metal ion.

[0068] Suitable rate modifiers of general structure (XX) are esters of malic acid with ethylene glycol, glycerol, or erythritol. Such esters may be monoesters or diesters of malic acid. Such esters may be monomeric, oligomeric, or polymeric.

[0069] Within the present context, the ester of malic acid with a polyhydric alcohol may contain additional ester groups formed with acids other than malic acid. Such acids are, in particular, acetic acid, propionic acid, and fatty acids. Thus, suitable rate regulators of general structure (XX) also include coesters of ethylene glycol, glycerol, or erythritol with malic acid and at least one of acetic acid, propionic acid, and fatty acids.

[0070] According to a particularly preferred embodiment, the rate regulator is selected from mono- and / or diglycerides of malic acid, which have the chemical structure of the following general formula (XXIIa) or (XXIIb): Thus, according to a preferred embodiment, the rate regulator of the present invention has the general structure (XXIIa) or (XXIIb): [ka] (In the formula, each R″ is, independently of the other, H or C(O)—R″″, provided that at least one R″ is not H; R'''' is an unbranched C2-C30 alkyl chain or an unbranched C2-C30 alkenyl chain, the alkenyl chain may contain 1-6 double bonds; Each R''' is, independently of the others, OM, where M is H or an alkali metal or alkaline earth metal ion, or is a moiety of the general structure (XXIII): [ka] Each R″ is, independently of the other, H or C(O)—R″″, where R″″ is an unbranched C2-C30 alkyl chain or an unbranched C2-C30 alkenyl chain, the alkenyl chain may contain 1-6 double bonds.

[0071] The rate regulator of the present invention may be a monoglyceride of malic acid or a mixture of different monoglycerides of malic acid. The rate regulator of the present invention may be a diglyceride of malic acid or a mixture of different diglycerides of malic acid. The rate regulator of the present invention may also be a mixture of one or more monoglycerides of malic acid and one or more diglycerides of malic acid. Preferably, the rate regulator of the present invention is a mixture of monoglycerides of malic acid and diglycerides of malic acid.

[0072] The moiety C(O)-R"" in the above general structures (XXII) and (XXIII) is preferably derived from a fatty acid. Preferred fatty acids present as esters in general structures (XXII) and (XXIII) are caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, basenic acid, linoleic acid, linoelaidic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, and docosahexanoic acid.

[0073] According to an embodiment, the rate modifier is a glycolic acid ester. In particular, the rate modifier is an ester of glycolic acid with a polyhydric alcohol. More preferred are mixed esters of glycolic acid and fatty acids with polyhydric alcohols.

[0074] According to an embodiment, the rate modifier has the following general structure (XXIV): [ka] where R is a branched or unbranched C2-C30 alkyl chain or a branched or unbranched C3-C30 alkenyl chain, which may contain 1-6 double bonds, or a cyclohexyl group, or an aromatic group having 5-10 C atoms.

[0075] Suitable rate modifiers of general structure (XXIV) are butyl glycolate, pentyl glycolate, hexyl glycolate, oleyl glycolate, stearyl glycolate, lauryl glycolate, prenyl glycolate, cyclohexyl glycolate, phenyl glycolate.

[0076] According to a further embodiment, the rate modifier is an ester of glycolic acid and a polyhydric alcohol. Such esters have the following general structure (XXV): [ka] wherein q is an integer from 0 to 4, preferably 1 or 2; R' are, independently of each other, H, or C(O)-R"", or a moiety of general structure (XXVI), with the proviso that at least one of R' is a moiety of general structure (XXVI); R"" is an unbranched C2-C30 alkyl chain or an unbranched C2-C30 alkenyl chain, which alkenyl chain may contain 1-6 double bonds; general structure (XXVI) is [ka] )

[0077] Suitable rate modifiers of general structure (XXV) are esters of glycolic acid with ethylene glycol, glycerol, or erythritol.

[0078] In the present context, the ester of glycolic acid and polyhydric alcohol may contain additional ester groups formed with acids other than glycolic acid. Such acids are, in particular, acetic acid, propionic acid, and fatty acids. Thus, suitable rate modifiers of general structure (XXV) also include coesters of ethylene glycol, glycerol, or erythritol with glycolic acid and at least one of acetic acid, propionic acid, and fatty acids.

[0079] According to a particularly preferred embodiment, the rate regulator is selected from monoglycerides of glycolic acid, which have the chemical structure of the following general formula (XXVII): Thus, according to a preferred embodiment, the rate regulator of the present invention has the general structure (XXVII): [ka] wherein each R″ is, independently of the other, H or C(O)—R″″, with the proviso that at least one R″ is not H, and R″″ is an unbranched C2-C30 alkyl chain or an unbranched C2-C30 alkenyl chain, which alkenyl chain may contain 1-6 double bonds.

[0080] The rate regulator of the present invention can be a monoglyceride of glycolic acid or a mixture of different monoglycerides of glycolic acid.

[0081] The moiety C(O)-R"" in general structure (XXVII) above is preferably derived from a fatty acid. Preferred fatty acids present as esters in general structure (XXVII) are caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, basenic acid, linoleic acid, linoelaidic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, and docosahexanoic acid.

[0082] According to an embodiment, the rate regulator is a mandelic acid ester. In particular, the rate regulator is an ester of mandelic acid with a polyhydric alcohol. More preferred are mixed esters of mandelic acid and fatty acids with polyhydric alcohols.

[0083] According to an embodiment, the rate modifier has the following general structure (XXVIII): [ka] where R is a branched or unbranched C2-C30 alkyl chain or a branched or unbranched C3-C30 alkenyl chain, the alkenyl chain may contain 1-6 double bonds, or a cyclohexyl group, or an aromatic group having 5-10 C atoms.

[0084] Suitable rate modifiers of general structure (XXVIII) are butyl mandelate, pentyl mandelate, hexyl mandelate, oleyl mandelate, stearyl mandelate, lauryl mandelate, prenyl mandelate, cyclohexyl mandelate, phenyl mandelate.

[0085] According to a further embodiment, the rate modifier is an ester of mandelic acid and a polyhydric alcohol. Such esters have the following general structure (XXIX): [ka] wherein q is an integer from 0 to 4, preferably 1 or 2; R' are, independently of each other, H or C(O)-R'''', or a moiety of general structure (XXX), with the proviso that at least one R' is a moiety of general structure (XXX); R'''' is an unbranched C2-C30 alkyl chain or an unbranched C2-C30 alkenyl chain, which alkenyl chain may contain 1-6 double bonds; and general structure (XXX) is [ka] )

[0086] Suitable rate modifiers of general structure (XXIX) are esters of mandelic acid with ethylene glycol, glycerol, or erythritol.

[0087] In this context, the ester of mandelic acid with a polyhydric alcohol can contain additional ester groups formed with an acid different from mandelic acid. Such acids are, in particular, acetic acid, propionic acid, and fatty acids. Thus, suitable rate regulators of general structure (XXIX) also include coesters of ethylene glycol, glycerol, or erythritol with mandelic acid and at least one of acetic acid, propionic acid, and fatty acids.

[0088] According to a particularly preferred embodiment, the rate regulator is selected from monoglycerides of mandelic acid, which have the chemical structure of the following general formula (XXXI): Thus, according to a preferred embodiment, the rate regulator of the present invention has the general structure (XXXI): [ka] wherein each R″ is, independently of the other, H or C(O)—R″″, with the proviso that at least one R″ is not H, and R″″ is an unbranched C2-C30 alkyl chain or an unbranched C2-C30 alkenyl chain, which alkenyl chain may contain 1-6 double bonds.

[0089] The rate regulator of the present invention can be a monoglyceride of mandelic acid or a mixture of different monoglycerides of mandelic acid.

[0090] The moiety C(O)-R"" in general structure (XXXI) above is preferably derived from a fatty acid. Preferred fatty acids present as esters of general structure (XXXI) are caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, linoelaidic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, and docosahexanoic acid.

[0091] According to embodiments, the rate modifier of the present invention may also be a mixture of two or more of the citrate, tartrate, lactate, gluconate, malate, glycolate, and / or mandelic acid esters, which may also apply to chemically different esters of the same acid.

[0092] The rate regulator of the present invention is preferably a solid. According to an embodiment, the rate regulator of the present invention is a solid having a particle size in the range of 0-2000 μm, preferably 250-1000 μm, more preferably 250-500 μm. It has been found that using a rate regulator with a particle size that is too small can lead to excessively long setting times, i.e., open times, of the mineral binder composition. It has also been found that a rate regulator with a particle size of more than 2000 μm can cause incomplete reaction of the rate regulator in the mineral binder composition, which can lead to reduced efficiency.

[0093] Particle size can be measured by sieve analysis according to standard ASTM C136 / C136M. In this process, fine and coarse particles are separated by passing the material through several sieves of different mesh sizes. The material to be analyzed is vibrated through a series of successively decreasing sieves using a single movement or a combination of horizontal, vertical or rotational movements. The result is the mass percentage of particles passing through a sieve of a given size. In this context, when a particle size range is given, the lower number refers to a sieve mesh size where >90% by weight, preferably >99% by weight of the particles are retained, while the higher number refers to a sieve mesh size where >90, preferably >99% by weight of the particles can still pass through.

[0094] Thus, it is preferred that the rate modifier present in the admixture of the present invention has a particle size, measured according to ASTM C136 / C136M, of 0 to 2000 μm, preferably 250 to 1000 μm, more preferably 250 to 500 μm.

[0095] Without wishing to be bound by theory, the inventors believe that the esters of hydroxycarboxylic acids are slowly hydrolyzed in the alkaline environment of the mineral binder mixed with water, and the hydroxycarboxylic acids are slowly released and act as retarders in the hydration, hardening, and / or drying of the mineral binder.

[0096] The admixture of the present invention also optionally comprises an accelerator. In this context, accelerator refers to an accelerator for the reaction of the mineral binder with water. Most preferably, the accelerator is an accelerator for the hydration of cement. Suitable accelerators in this context are selected from hydroxides, nitrates, nitrites, thiocyanates, chlorides, carbonates, bicarbonates, or silicates of alkali metals or alkaline earth metals. Suitable accelerators are also aluminum salts or aluminates. Preferred accelerators are sodium silicate, sodium thiocyanate, sodium carbonate, sodium bicarbonate, calcium hydroxide, calcium chloride, calcium nitrate, calcium nitrite, or aluminum sulfate. According to an embodiment, an accelerator is present in the admixture of the present invention, said accelerator being selected from hydroxides, nitrates, nitrites, thiocyanates, chlorides, carbonates, bicarbonates, silicates, or aluminum salts of alkali metals or alkaline earth metals, preferably selected from sodium silicate, sodium thiocyanate, sodium carbonate, sodium bicarbonate, calcium hydroxide, calcium chloride, calcium nitrate, calcium nitrite, or aluminum sulfate.

[0097] According to an embodiment, the admixture of the invention comprises at least one rate modifier selected from citrate, tartrate, lactate, gluconate, malate, glycolate, and / or mandelate.

[0098] According to a further embodiment, the admixture of the present invention consists of at least one rate modifier selected from citrate, tartrate, lactate, gluconate, malate, glycolate, and / or mandelic acid esters, and a solvent, preferably water.

[0099] According to yet another embodiment, the admixture of the invention comprises (in each case relative to the total weight of the admixture): a) 1 to 99 wt. % of at least one rate modifier selected from esters of hydroxycarboxylic acids; b) 1 to 99% by weight of an accelerator for the hydration of cement; c) optionally water; Includes.

[0100] Preferred esters of hydroxycarboxylic acids are citrate, tartrate, lactate, gluconate, malate, glycolate, and / or mandelate.

[0101] The admixture of the invention is preferably water-free, meaning that the water content is less than 5% by weight, preferably less than 1% by weight, relative to the total weight of the admixture.

[0102] According to an embodiment, the admixture of the present invention is in liquid form. The liquid form may be a solution or suspension of at least one rate modifier and optionally an accelerator in a liquid, preferably in water. According to a further embodiment, the admixture of the present invention is in solid form. In this specification, solid form refers to a powdery material. Thus, the admixture of the present invention may be a powder. The admixture of the present invention that is a solid may contain at least one rate modifier and / or optionally an accelerator adsorbed on a carrier, which is preferred in certain cases. A suitable carrier is, for example, silica.

[0103] According to an embodiment, the admixture of the present invention is a single-component admixture. This means that all the contents of the admixture are present in one component. Usually, one component is one spatial compartment. Single-component admixtures are particularly easy to handle and administer. According to another embodiment, the admixture of the present invention is a multi-component admixture, preferably a two-component admixture. In a multi-component admixture, the contents of the admixture are distributed in different spatial compartments. Thus, a two-component admixture of the present invention has its contents separated into two spatially separated compartments. It may be particularly preferred to spatially separate at least one rate modifier from the accelerator and optionally water. This may improve the storage stability of the admixture. A multi-component admixture may have the advantage of improved storage stability, facilitating separate administration of a single content.

[0104] In a further aspect, the present invention also relates to a method for reducing the maximum heat flow of a mineral binder composition, said method comprising the step of adding to said mineral binder composition an admixture as described above.

[0105] The mineral binder composition is as described above.

[0106] The preferred embodiments described above shall also apply to such methods.

[0107] In a further aspect, the present invention provides a method for producing a composition comprising the steps of: a) at least one cement; b) at least one rate regulator selected from esters of hydroxycarboxylic acids, in particular citrates, tartrates, lactates, gluconates, malates, glycolates and / or mandelic acid esters, c) optionally an aggregate; d) optionally further additives; e) optionally water; The present invention relates to a cementitious composition, in particular a cement or concrete, comprising:

[0108] Preferred esters of hydroxycarboxylic acids are citrate, tartrate, lactate, gluconate, malate, glycolate, and / or mandelate.

[0109] According to an embodiment, at least one cement is added to the cementitious composition of the present invention at a concentration of 50 to 600 kg / m 3 , preferably 100 to 500 kg / m 3 , and even more preferably 150 to 400 kg / m 3The rate modifier is present in an amount of 0.01 to 10% by weight, preferably 0.05 to 5% by weight, more preferably 0.1 to 2% by weight, even more preferably 0.25 to 1% by weight, in each case based on the total dry weight of cement. The aggregate is optionally present in an amount of 500 to 3500 kg / m 3 , preferably 800 to 3000 kg / m 3 The further additives are optionally present in an amount of 0.1 to 10% by weight based on the total dry weight of the cement. Water is optionally present in a water to cement weight ratio of 0.1 to 0.8, preferably 0.2 to 0.6, more preferably 0.25 to 0.5.

[0110] According to a further embodiment, the at least one cement is present in the cementitious composition of the invention in an amount of 5 to 95% by weight, preferably 10 to 60% by weight, based on the total dry weight of the cementitious composition. The rate modifier is present in an amount of 0.01 to 10% by weight, preferably 0.05 to 5% by weight, more preferably 0.1 to 2% by weight, even more preferably 0.25 to 1% by weight, based on the total dry weight of the cement. The aggregate is present in an amount of 5 to 85% by weight, preferably 20 to 80% by weight, based on the total dry weight of the cementitious composition. The further additives are optionally present in an amount of 0.1 to 10% by weight, based on the total dry weight of the cement. The water is optionally present in a water to powder weight ratio of 0.1 to 0.6, preferably 0.2 to 0.5, more preferably 0.2 to 0.4.

[0111] According to a further embodiment, the at least one cement is present in the cementitious composition of the invention in an amount of 20-75% by weight, preferably 30-50% by weight, relative to the total dry weight of the cementitious composition. The rate modifier is present in an amount of 0.01-10% by weight, preferably 0.05-5% by weight, more preferably 0.1-2% by weight, even more preferably 0.25-1% by weight, in each case relative to the total dry weight of the cement. The aggregate is present in an amount of 24-75% by weight, preferably 30-60% by weight, relative to the total dry weight of the cementitious composition. The further additives are optionally present in an amount of 0.1-10% by weight, relative to the total dry weight of the cement. The water is optionally present in a water to powder weight ratio of 0.1-0.6, preferably 0.2-0.5, more preferably 0.2-0.4.

[0112] The cementitious composition of the invention may be a dry cementitious composition. Dry composition means that the amount of water present in such composition is less than 5% by weight, preferably less than 1% by weight, relative to the total weight of the cementitious composition. The dry cementitious composition may be cement, dry mortar or dry concrete, in particular dry concrete. The cementitious composition of the invention may also comprise water. Thus, the cementitious composition may also be a wet cementitious composition. The wet cementitious composition may be a mortar, grout, screed, adhesive, levelling compound or concrete, in particular concrete. Preferably, the wet cementitious composition of the invention is obtained by mixing a dry cementitious composition with water. Such mixing is in particular carried out before application of the cementitious composition. The hardening of the cementitious composition starts upon mixing with water. According to an embodiment, the amount of water added to the dry cementitious composition of the invention is such that the weight ratio of water to cement is between 0.1 and 1.0, preferably between 0.2 and 0.6, more preferably between 0.25 and 0.4.

[0113] At least one rate modifier selected from citrate, tartrate, lactate, gluconate, malate, glycolate, and / or mandelic acid esters in the cementitious composition of the present invention is as described above.

[0114] The at least one cement may in particular be a Portland cement of type CEM I, CEM II, CEM III, CEM IV and CEM V according to standard EN197-1, a Portland cement of type CEM VI according to standard DIN EN197-5, a calcium aluminate cement according to standard EN 14647 and / or a calcium sulfoaluminate cement. Cements according to other standards are likewise included, for example Portland cement according to standard ASTM C140-05 or according to Chinese, Japanese, Indian or other standards. Mixtures of any two or more of these cements are also possible. It is particularly preferred that the at least one cement comprises a Portland cement of type CEM I, CEM II, CEM III, CEM IV or CEM V according to standard EN197-1 or a Portland cement of type CEM VI according to standard EN197-5 or a Portland cement according to standard ASTM C140-05. Likewise, it is particularly preferred that the at least one cement essentially consists of Portland cement of type CEM I, CEM II, CEM III, CEM IV or CEM V as described in standard EN 197-1, or of type CEM VI as described in standard DIN EN 197-5, or of Portland cement according to standard ASTM C140-05. Optionally, the Portland cement further comprises calcium sulfate in an amount of not more than 20% by weight, preferably not more than 10% by weight, relative to the total dry weight of the cement.

[0115] The aggregates can be any aggregates typically used in construction materials. Typical aggregates are, for example, rocks, crushed stone, gravel, sand, especially quartz sand, river sand and / or processed sand, slag, microsilica, fly ash, recycled concrete, glass, expanded glass, hollow glass beads, glass ceramics, volcanic rocks, boulders, pumice, perlite, vermiculite, quarry waste, raw, calcined or fused earth or clay, porcelain, fused or sintered abrasives, calcined supports, silica xerogels. The aggregates can also be biologically derived aggregates, for example hemp fibers. In this context, aggregates also include fillers, for example finely ground limestone. Aggregates useful in the present invention can have any shape and size typically found in such aggregates. Particularly preferred aggregates are sand and / or gravel. Sand and gravel are natural granular materials composed of finely divided rock or mineral particles. Typically, sand and gravel are composed of siliceous and / or calcareous materials. Sand and gravel are available in various forms and sizes. Suitable sand in the present context may have a particle size of 0.063 to 2 mm. Suitable gravel particle sizes may be 2 to 32 mm. However, other particle sizes are also possible. Examples of suitable sands are quartz sand, limestone sand, river sand or crushed aggregates. Suitable aggregates are described, for example, in the standard EN 12620:2013. Of course, mixtures of aggregates are also possible.

[0116] The further additives may be any additives common to the mortar and concrete industry. In particular, the further additives may be selected from plasticizers, superplasticizers, shrinkage reducing agents, air entrainers, deaeration agents, stabilizers, viscosity modifiers, thickeners, water reducers, retarders, accelerators, water resistance agents, fibers, foaming agents, defoamers, redispersible polymer powders, dedusting agents, chromate reducing agents, pigments, biocides, corrosion inhibitors, and steel passivators. Naturally, mixtures of two or more of these additives are also possible.

[0117] According to a preferred embodiment, the cementitious composition of the present invention comprises at least one plasticizer or superplasticizer selected from lignosulfonates, melamine formaldehyde sulfonates, and polycarboxylate ethers.

[0118] According to a further preferred embodiment, the cementitious composition of the present invention further comprises at least one accelerator selected from the hydroxides, nitrates, nitrites, thiocyanates, chlorides, carbonates, bicarbonates or silicates of alkali metals or alkaline earth metals, or aluminum salts, preferably sodium silicate, sodium thiocyanate, sodium carbonate, sodium bicarbonate, calcium hydroxide, calcium chloride, calcium nitrate, calcium nitrite or aluminum sulfate.

[0119] According to a preferred embodiment, at least one rate regulator in the cementitious composition of the present invention is selected from mono- and / or diglycerides of citric acid. The mono- and / or diglycerides of citric acid are as described by the general structure (IV) above. According to another preferred embodiment, at least one rate regulator in the cementitious composition of the present invention is selected from mono- and / or diglycerides of tartaric acid. According to yet another preferred embodiment, at least one rate regulator in the cementitious composition of the present invention is selected from lactate and / or gluconate.

[0120] According to further preferred embodiments, the rate regulator is present in the cementitious composition of the invention in an amount of 0.01 to 10% by weight, preferably 0.05 to 5% by weight, more preferably 0.1 to 2% by weight, even more preferably 0.25 to 1% by weight, in each case relative to the total dry weight of the cement.

[0121] Thus, preferred cementitious compositions of the present invention include a) at least one cement selected from Portland cement, calcium aluminate cement and / or calcium sulfoaluminate cement, preferably Portland cement; b) at least one rate regulator selected from mono- and / or diglycerides of citric acid of general structure (IV) in an amount of 0.01 to 10% by weight, preferably 0.05 to 5% by weight, more preferably 0.1 to 2% by weight, even more preferably 0.25 to 1% by weight, based on the total dry weight of the cement; and c) optionally consisting of 0.01 to 5% by weight, preferably 0.1 to 4% by weight, more preferably 0.2 to 3% by weight, of at least one accelerator selected from alkali metal or alkaline earth metal hydroxides, nitrates, nitrites, thiocyanates, chlorides, carbonates, bicarbonates or silicates, or aluminium salts, preferably sodium silicate, sodium thiocyanate, sodium carbonate, sodium bicarbonate, calcium hydroxide, calcium chloride, calcium nitrate, calcium nitrite or aluminium sulphate, based on the total dry weight of the cement.

[0122] Another preferred cementitious composition of the present invention comprises a) 5 to 95% by weight, based on the total dry weight of the cementitious composition, of at least one cement selected from Portland cement, calcium aluminate cement and / or calcium sulfoaluminate cement, preferably Portland cement; b) at least one rate regulator selected from mono- and / or diglycerides of citric acid of general structure (IV) in an amount of 0.01 to 10% by weight, preferably 0.05 to 5% by weight, more preferably 0.1 to 2% by weight, even more preferably 0.25 to 1% by weight, based on the total dry weight of the cement; c) optionally, 5 to 95% by weight of sand and / or gravel, based on the total dry weight of the cementitious composition; d1) optionally, 0.01 to 3% by weight, based on the total dry weight of cement, of at least one plasticizer or superplasticizer; d2) optionally, 0.01-5% by weight, preferably 0.1-4% by weight, more preferably 0.2-3% by weight, of at least one accelerator selected from alkali metal or alkaline earth metal hydroxides, nitrates, nitrites, thiocyanates, chlorides, carbonates, bicarbonates or silicates or aluminum salts, preferably sodium silicate, sodium thiocyanate, sodium carbonate, sodium bicarbonate, calcium hydroxide, calcium chloride, calcium nitrate, calcium nitrite or aluminum sulfate, based on the total dry weight of the cement; e) optionally, water in a weight ratio to cement of 0.1 to 1.0, preferably 0.2 to 0.6, more preferably 0.25 to 0.4; The present invention comprises or consists essentially of

[0123] According to a preferred embodiment, the cementitious composition according to the invention is characterized in that the maximum calorific value is less than or equal to 3 mW / g and the open time is less than or equal to 60 hours.

[0124] In the present context, the term "retardation" refers to the retardation of the setting of the mineral binder composition (measured herein as an increase in the open time, which corresponds to an inhibition of the onset of hydration of the hydraulic binder) and / or the retardation of the hardening of the mineral binder composition (measured herein as a decrease in tensile strength after a given time).

[0125] The cementitious composition of the present invention can be obtained by intergrinding and / or intermixing the mineral binder composition described above with the admixture described above.

[0126] Thus, in a further aspect, the present invention relates to a process for producing a cementitious composition, said process comprising the steps of: a1) co-grinding cement or cement clinker with the above admixtures, or a2) intermixing a mineral binder composition with the above admixture.

[0127] The cementitious composition, cement and mineral binder composition are as described above. In particular, the cementitious composition and the mineral binder composition may be cement, dry mortar, dry concrete, mortar, grout, screed, adhesive, leveling compound or concrete, in particular dry concrete or concrete.

[0128] Preferably, the cement or cement clinker comprises Portland cement, calcium aluminate cement and / or calcium sulphoaluminate cement, preferably Portland cement of type CEM I, CEM II, CEM III, CEM IV or CEM V as described in standard EN 197-1 or Portland cement of type CEM VI as described in standard DIN EN 197-5 or Portland cement according to standard ASTM C140-05, particularly preferably, the cement or cement clinker essentially consists of Portland cement, calcium aluminate cement and / or calcium sulphoaluminate cement, preferably essentially consists of Portland cement of type CEM I, CEM II, CEM III, CEM IV or CEM V as described in standard EN 197-1 or Portland cement of type CEM VI as described in standard DIN EN 197-5 or Portland cement according to standard ASTM C140-05. Cement clinker is the raw cement from the cement kiln that has not yet been ground or mixed with any other ingredients. Cement clinker in this context refers to the same type of cement as above, but before it has been ground.

[0129] Step a1), if present, is preferably carried out during the production of cement. Preferably, the admixture of the present invention is interground with cement clinker, particularly preferably with Portland cement clinker, since the cement clinker is typically ground to the desired fineness during the production of cement. Thus, the intergrounding of the admixture of the present invention with the cement clinker can save a process step. However, it is also possible to interground the admixture of the present invention with the abovementioned cement, in particular with Portland cement, which has already been ground and optionally blended with other components of the cement.

[0130] The method of mutually grinding the cement clinker or cement with the admixture is known per se to the person skilled in the art and is not particularly limited. For example, the mutual grinding in step a1) can be carried out in a ball mill or a vertical roller mill.

[0131] Step a2) concerns, if present, a mineral binder composition as described above. According to an embodiment of the invention, the mineral binder composition is concrete or mortar or cement, in particular concrete. According to a preferred embodiment, the mineral binder composition is concrete comprising Portland cement.

[0132] According to an embodiment, the process for producing the cementitious composition of the present invention further comprises the step of mixing the composition obtained in step a1 or a2 with at least one of an aggregate, a further additive, and water.

[0133] According to an embodiment, the process for producing the cementitious composition of the present invention is characterized in that the admixture is added in an amount such that the amount of rate modifier relative to the cement is 0.01-10% by weight, preferably 0.05-5% by weight, more preferably 0.1-2% by weight, and even more preferably 0.25-1% by weight.

[0134] According to an embodiment, the process for producing the cementitious composition of the present invention, in which at least water is further admixed, further comprises a step of hardening the mineral binder composition.

[0135] In another aspect, the present invention relates to the use of an admixture as described above in the manufacture of a mineral binder composition, in particular a cement or cementitious composition, in particular a mineral binder composition, a cement or a cementitious composition as described above.

[0136] In particular, the present invention relates to the use of an admixture in the manufacture of a mineral binder composition, said admixture comprising: a) at least one rate modifier selected from esters of hydroxycarboxylic acids; b) optionally an accelerator for the hydration of cement; c) optionally water; comprising or consisting of In this case, the at least one rate regulator is selected from mono- and / or diglycerides of citric acid, mono- and / or diglycerides of tartaric acid, mono- and / or diglycerides of lactic acid, mono- and / or diglycerides of gluconic acid, mono- and / or diglycerides of malic acid, mono- and / or diglycerides of glycolic acid, mono-glycerides of mandelic acid.

[0137] Particularly preferably, in such uses, the at least one rate modifier is selected from citrate esters of general structure (IV). [Brief description of the drawings]

[0138] [Figure 1] The heat flow curves measured for Examples 2 to 6 are shown. The points on the heat flow curve used to determine the maximum heat flow and the heat flow at 60 hours are shown in Figure 1. The open time is shown in Figure 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0139] As can be seen in Figure 1, the open time is measured from the start of mixing to the time when the heat flow curve first starts to increase. The maximum heat flow corresponds to the global maximum of the heat flow curve (early peaks detected within the first 15 minutes after mixing are ignored as they are related to mixing). EXAMPLES

[0140] The heat flow curves were measured in an isothermal process as described in standard ASTM C1702-17. The examples were measured using a Calmetrix instrument i-CAL8000.

[0141] The maximum heat flow reported in the table below is the overall maximum of the heat flow curve, the heat flow at 60 hours after mixing with water is shown in the table below, and the open time shown in the table below is the time when the heat flow curve begins to increase. In determining the maximum heat flow and open time, the initial peak in heat flow that occurs within about the first 15 minutes after mixing is ignored since this heat flow is more relevant to the mixing process.

[0142] The tensile strength was measured according to standard DIN EN196-1:2005-05.

[0143] Example 1 Mortar samples were prepared at 20°C by mixing 1 part by weight of cement (CEM III / B42.5N), 3 parts by weight of CEN standard sand according to EN196-1, and 0.5 parts by weight of water. To mix, the water and cement were added to the mixer bowl. After mixing at low speed for 30 seconds, the sand was added over 30 seconds. After the sand addition was completed, mixing was continued at a higher speed for another 30 seconds. Mixing was then stopped for 90 seconds and the mortar was scraped off the walls of the mixing bowl. Mixing was then continued at high speed for another 60 seconds. Each retarder of the type shown in Table 1 below was added with the mixing water in an amount of 0.125% by weight based on the dry weight of the cement. Table 1 below shows an overview of Examples 1-1 to 1-5 (all of Examples 1-1 to 1-5 are comparative examples and are not according to the present invention).

[0144] The results were measured as described above.

[0145] [Table 1]

[0146] From the results in Table 1 above, it can be seen that state of the art retarders do not reduce maximum heat flow to the desired extent, and state of the art retarders naturally significantly delay the onset of setting (i.e., increase open time).

[0147] Example 2 Mortar samples were prepared at 20°C by mixing 1 part by weight of cement (CEM III / B42.5N), 3 parts by weight of CEN standard sand according to EN196-1, and 0.5 parts by weight of water. To mix, the water and cement were added to the mixer bowl. After mixing at low speed for 30 seconds, the sand was added over 30 seconds. After the sand addition was completed, mixing was continued at a higher speed for another 30 seconds. Mixing was then stopped for 90 seconds and the mortar was scraped off the walls of the mixing bowl. Mixing was then continued at high speed for another 60 seconds. The rate moderator and accelerator (if present) were added along with the mixing water. Tables 2 and 3 below provide an overview of Examples 2-1 to 2-10 (Example 2-1 is a reference example not according to the invention, Examples 2-2 to 2-10 are according to the invention). In Tables 2 and 3, the type and amount of rate moderator used is given in weight % based on the dry cement weight.

[0148] The results were measured as described above.

[0149] [Table 2]

[0150] Citrate esters of mono- and diglycerides with different particle sizes were used in Examples 2-2 to 2-4 (particle sizes are reported in the "Rate Modifier" column). From the results in Table 2, it can be seen that all rate modifiers significantly reduced the maximum heat flow. At the same time, the retardation effect was still acceptable for practical use. However, the intermediate fraction (Example 2-3) showed particularly good results, reducing the maximum heat flow by 53%. When the citrate esters of mono- and diglycerides were very fine (Example 2-2), the open time was longer, resulting in a smaller reduction in the maximum heat flow. This is presumably because the rate modifier was consumed rather quickly. On the other hand, when the citrate esters of mono- and diglycerides were rather coarse (Example 2-4), the reduction in the maximum heat flow was good, but the set retardation was also stronger (as is evident from the tensile strength value).

[0151] Therefore, in the following, all experiments using citrate esters of mono- and diglycerides were carried out with the intermediate fraction of particle size between 250 and 500 μm.

[0152] Table 3 below shows the results of Examples 2-5-2-10 using different dosages of citric acid esters of mono- and diglycerides with particle sizes of 250-500 μm.

[0153] [Table 3]

[0154] All examples in Table 3 show a significant reduction in maximum heat flow with a concomitant increase in open time that is still acceptable in practice. Examples 2-5 to 2-10 show that increasing dosage leads to increasing reduction in maximum heat flow. However, Example 2-10 shows that at a dosage of 2.0 wt.%, the delay begins to become noticeable.

[0155] Example 3 Examples 3-1 to 3-4 were prepared in a similar manner to Examples 2-2 to 2-10. Citric acid esters of mono- and diglycerides with particle sizes of 250 to 500 μm (also known as E472c emulsifier) ​​were used as the rate moderator in all examples. Calcium nitrate was used as the accelerator in all examples. The accelerator was added together with the rate moderator. Table 4 below shows the dosage of rate moderator and accelerator in weight % based on dry cement weight. Examples 3-1 to 3-4 are according to the present invention. Measurements were performed as described above. The results of the measurements are also shown in Table 4.

[0156] [Table 4]

[0157] As can be seen from the results in Table 4, the use of a combination of rate modifier and accelerator significantly reduces the maximum heat flow (see Examples 3-1 to 3-4 and Example 2-1). The additional use of accelerator reduces the open time for a given dosage of rate modifier (see Examples 3-2 and 3-3 and Example 2-3, and Examples 3-4 and 2-8). Also, the tensile strength can be increased by the additional use of accelerator (see 2d tensile strengths for Examples 3-2 and 3-3 and Example 2-3, and 2d and 7d tensile strengths for Examples 3-4 and 2-8).

[0158] Example 4 For the preparation of Examples 4-1 to 4-3, Portland cement CEM I 42.5N was dry mixed with each rate moderator by vigorously shaking until visually homogeneous. The type and amount of rate moderator added was as shown in Table 5 below. The weight percent refers to the weight percent of rate moderator relative to the total dry weight of cement. Then, an amount of water was added to achieve a water / cement ratio of 0.35. Mixing was then continued for 1 minute at 1000 rpm in a Heidolph propeller mixer. All mixing procedures were performed at 23°C and 50% relative humidity.

[0159] Examples 4-2 and 4-3 are according to the present invention. Example 4-1 is a reference example and is not according to the present invention.

[0160] [Table 5]

[0161] The results in Table 4 show that both the citrate esters of mono- and diglycerides and the diacetyl tartaric acid esters of mono- and diglycerides reduce the maximum heat flow while still providing a delay that is acceptable for practical purposes.

[0162] Example 5 To prepare the microconcrete examples 5-1 to 5-7, 750 g of cement and 3890 g of aggregate (particle size 0-8 mm) were dry mixed. The type and amount of rate modifiers shown in Table 6 below were added to the resulting dry mix and intermixed until visually uniform. 315 g of water were added and mixing was continued for 1 minute at 1000 rpm in a Heidolph propeller mixer. All mixing procedures were performed at 25°C and 50% relative humidity. The microconcrete thus prepared was poured in a prismatic shape (12 x 12 x 13.5 cm) in an isolated box made of Styrofoam. An Eltek Squirrel 1000 series data logger (DIN IEC 584 type K, diameter 0.22 mm) equipped with Ni / CrNi thermocouples was used. 2 A 1000 Ω resistor (4.5 ohm / m resist) was used to measure the core temperature under semi-adiabatic conditions. For this, a probe was poured into the microconcrete cube and connected to a data logger unit through a mounting hole in the Styrofoam insulation box. The maximum concrete core temperature was recorded, as well as the time to reach the maximum core temperature and the time for the core temperature to drop to 25°C.

[0163] The following Table 6 shows Examples 5-1 to 5-7 and the measurement results. Example 5-1 is a reference example and is not according to the present invention. Examples 5-2 to 5-7 are according to the present invention.

[0164] [Table 6]

[0165] Different particle sizes of citric acid esters of mono- and diglycerides were used in Examples 5-2 to 5-4 and 5-5 to 5-7, respectively (particle sizes are reported in the "Rate Modifier" column). The results show that the maximum core temperature of the cast microconcrete was significantly reduced in all cases. The larger particle size of citric acid esters of mono- and diglycerides, 1 to 2 mm, reduces it even more compared to the particle size of only 0.5 to 1 mm. The retardation (measured as the increase in the time required to reach the maximum core temperature and the time required to cool to 25°C) of all samples was still acceptable for practical use. It was found that the higher the dosage of the rate modifier, the stronger the retardation.

Claims

1. a) at least one rate modifier selected from esters of hydroxycarboxylic acids; b) optionally an accelerator for the hydration of cement; c) optionally water; 1. An admixture for a mineral binder composition comprising or consisting of:

2. a) 1 to 99 wt. % of at least one rate modifier selected from esters of hydroxycarboxylic acids; b) 1 to 99% by weight of an accelerator for the hydration of cement; c) optionally water; 2. The admixture according to claim 1, characterized in that it comprises (in each case relative to the total weight of the admixture):

3. 3. The admixture according to claim 1 or 2, characterized in that the at least one rate modifier is selected from citrate esters, tartaric acid esters, lactate esters, gluconate esters, malate esters, glycolate esters, and / or mandelic acid esters.

4. 3. The admixture according to claim 1 or 2, characterized in that the at least one rate regulator is selected from mono- and / or diglycerides of citric acid, mono- and / or diglycerides of tartaric acid, monoglycerides of lactic acid, monoglycerides of gluconic acid, mono- and / or diglycerides of malic acid, monoglycerides of glycolic acid, monoglycerides of mandelic acid.

5. 3. An admixture according to claim 1 or 2, characterized in that an accelerator is present, said accelerator being selected from alkali or alkaline earth metal hydroxides, nitrates, nitrites, thiocyanates, chlorides, carbonates, bicarbonates or silicates, or aluminium salts, preferably sodium silicate, sodium thiocyanate, sodium carbonate, sodium bicarbonate, calcium hydroxide, calcium chloride, calcium nitrate, calcium nitrite or aluminium sulphate.

6. 3. The admixture according to claim 1 or 2, characterized in that the rate modifier has a particle size, measured according to ASTM C136 / C136M, of 0 to 2000 μm, preferably 0 to 1000 μm, more preferably 0 to 500 μm, even more preferably 250 to 500 μm.

7. The at least one rate modifier has the general structure (IV): 【Chemical 1】 (In the formula, each R" is, independently of the other, H or C(O)-R"", provided that at least one R" is not H; R"" is an unbranched C2-C30 alkyl chain or an unbranched C2-C30 alkenyl chain, wherein the alkenyl chain may contain 1 to 6 double bonds; Each R''' is, independently of the other, OM, where M is H or an alkali metal or alkaline earth metal ion, or is a moiety of the following general structure (V): 【Chemistry 2】 3. An admixture according to claim 1 or 2, characterized in that each R" is, independently of the others, H or C(O)-R"", where R"" is an unbranched C2-C30 alkyl chain or an unbranched C2-C30 alkenyl chain, said alkenyl chain may contain 1 to 6 double bonds) selected from citrate esters.

8. a) at least one cement; b) at least one rate modifier selected from esters of hydroxycarboxylic acids, in particular citrates, tartarates, lactates, gluconates, malates, glycolates, and / or mandelates; c) optionally agglomerates; d) optionally further additives; e) optionally water; 1. A cementitious composition, in particular cement or concrete, comprising:

9. 9. The cementitious composition according to claim 8, characterized in that the rate modifier is present in an amount of 0.01 to 10% by weight, preferably 0.05 to 5% by weight, more preferably 0.1 to 2% by weight, and even more preferably 0.25 to 1% by weight, in each case relative to the total dry weight of the cement.

10. 10. Cementitious composition according to claim 8 or 9, characterized in that the cement comprises or consists of Portland cement, calcium aluminate cement and / or calcium sulfoaluminate cement, preferably Portland cement of type CEM I, CEM II, CEM III, CEM IV or CEM V according to standard EN 197-1, or Portland cement of type CEM VI according to standard DIN EN 197-5, or Portland cement according to standard ASTM C140-05.

11. 10. The cementitious composition according to claim 8 or 9, characterized in that it further comprises an accelerator selected from alkali metal or alkaline earth metal hydroxides, nitrates, nitrites, thiocyanates, chlorides, carbonates, bicarbonates or silicates, or aluminum salts, preferably sodium silicate, sodium thiocyanate, sodium carbonate, sodium bicarbonate, calcium hydroxide, calcium chloride, calcium nitrate, calcium nitrite or aluminum sulfate.

12. a1) inter-grinding cement or cement clinker with an admixture according to claim 1 or 2, or a2) intermixing a mineral binder composition with an admixture according to claim 1 or 2, 10. A process for producing the cementitious composition of claim 8 or 9, comprising:

13. 13. The process according to claim 12, characterized in that the cement or cement clinker comprises Portland cement of type CEM I, CEM II, CEM III, CEM IV or CEM V according to standard EN 197-1, or Portland cement of type CEM VI according to standard DIN EN 197-5, or Portland cement according to standard ASTM C140-05, particularly preferably the cement or cement clinker consists essentially of Portland cement of type CEM I, CEM II, CEM III, CEM IV or CEM V according to standard EN 197-1, or Portland cement of type CEM VI according to standard DIN EN 197-5, or Portland cement according to standard ASTM C140-05.

14. 13. The process according to claim 12, further comprising the step of mixing the composition obtained in step a1 or a2 with at least one of a flocculant, further additives, and water.

15. 13. The process according to claim 12, characterized in that the admixture is added in an amount such that the weight ratio of the rate moderator to the cement is 0.01 to 10 wt.%, preferably 0.05 to 5 wt.%, more preferably 0.1 to 2 wt.%, even more preferably 0.25 to 1 wt.%.

16. 3. A method for reducing the maximum heat flow of a mineral binder composition, comprising the step of adding the admixture of claim 1 or 2 to the mineral binder composition.

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