An ultrafine low-carbon cementing material suitable for low-carbon building materials and a preparation method thereof

Abstract

The application discloses a kind of ultrafine low-carbon cementing material suitable for low-carbon building materials and a preparation method thereof, the ultrafine low-carbon cementing material includes, by weight parts, blast furnace slag powder 5-20 weight parts, fly ash 5-20 weight parts, activator 0.5-3 weight parts.The ultrafine low-carbon cementing material suitable for low-carbon building materials and the preparation method thereof provided by the application are produced using industrial solid waste, can replace part of cement clinker when mixed into cement, can replace part of cement in equal amount when mixed into concrete products, and significantly improve the working performance, mechanical properties and durability of cement and concrete products, while also increasing the absorption capacity of cement and concrete products for industrial solid waste, reducing production costs and reducing carbon dioxide emissions.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of building materials, and particularly relates to a superfine low-carbon cementitious material suitable for low-carbon building materials and a preparation method thereof. BACKGROUND

[0002] The building material industry is a major carbon emitter, and 0.8 tons of carbon dioxide are emitted per ton of cement clinker produced. In order to achieve the national double carbon target, carbon emission reduction in the cement industry is imminent. Therefore, using superfine low-carbon cementitious material to replace raw materials is the key to carbon emission reduction in the cement industry.

[0003] Therefore, with the continuous promotion of the national double carbon policy, how to use industrial solid wastes such as blast furnace slag and fly ash as raw materials to prepare green building materials such as "low-carbon cement" and "low-carbon concrete" will become the only way for the sustainable development of the building material industry. SUMMARY

[0004] In view of the above technical problems, the application provides a superfine low-carbon cementitious material suitable for low-carbon building materials and a preparation method thereof. The superfine low-carbon cementitious material is produced from industrial solid wastes. When mixed into cement, it can replace cement clinker. When mixed into concrete products, it can replace part of the cement in equal amount, and significantly improve the workability, mechanical properties and durability of the cement and concrete products. At the same time, it can also increase the consumption of industrial solid waste by cement and concrete products, reduce production cost and reduce carbon dioxide emission.

[0005] The superfine low-carbon cementitious material suitable for low-carbon building materials provided by the application comprises, by weight, 5-20 parts of blast furnace slag powder, 5-20 parts of fly ash and 0.5-3 parts of an activator.

[0006] Preferably, the specific surface area of the blast furnace slag powder is greater than 400 m 2 / kg, and the 28-day activity index is greater than 95%.

[0007] Preferably, the specific surface area of the fly ash is greater than 300 m 2 / kg, and the 28-day activity index is greater than 70%.

[0008] Preferably, the activator comprises an organic base.

[0009] Preferably, the organic base is triethanolamine and / or triisopropanolamine.

[0010] Preferably, the activator further comprises a modified silicate.

[0011] Preferably, the modified silicate is phosphonated silicate.

[0012] In the present application, the organic base is used to promote the dissolution of mineral phase, and when used with the modified silicate inorganic base, the activation effect is better; the organic base forms a complex with the ions of the mineral phase, accelerates the dissolution of the ions of the mineral phase in the cementitious material, generates a stable coordination compound, and improves the supersaturation of the ions in the solution; the modified silicate as the main component of the inorganic base can activate the materials with pozzolanic activity such as blast furnace slag powder and fly ash, and promote the hydration of the mineral phase.

[0013] Preferably, the phosphonated silicate is modified by using an alkylene ammonium salt to organically intercalate the silicate, and then copolymerized with an alkylene phosphonic acid to obtain;

[0014] Preferably, the alkylene ammonium salt is at least one of acryloyloxyethyl trimethyl ammonium chloride, methacryloyloxyethyl trimethyl ammonium chloride or trimethyl vinyl ammonium bromide; the silicate is montmorillonite and / or saponite; and the alkylene phosphonic acid is at least one of vinyl phosphonic acid, sodium vinyl phosphate or potassium vinyl phosphonate.

[0015] In the present application, the copolymer of the alkylene ammonium salt and the alkylene phosphonic acid in the phosphonated silicate has good compatibility with the activator of the organic base, and the synergistic effect of the combination of the two is enhanced; and the phosphonic group is a functional group with stronger adsorption capacity, which can promote the adsorption of the activator on the surface of the blast furnace slag powder and fly ash particles, so that the phosphonated silicate as the activator can obtain better dispersion effect, thereby helping to play the activation effect.

[0016] Preferably, the weight ratio of the organic base to the modified silicate is 1:5-20.

[0017] The present application also provides a preparation method of the above-mentioned ultra-fine low-carbon cementitious material suitable for low-carbon building materials, which comprises: adding blast furnace slag powder, fly ash and an activator into a ball mill in parts by weight for ultra-fine grinding, to obtain the ultra-fine low-carbon cementitious material suitable for low-carbon building materials.

[0018] Preferably, the ball mill adopts an open circuit grinding system.

[0019] Preferably, the ultra-fine grinding time is 30-40 min.

[0020] Preferably, the specific surface area of the ultra-fine low-carbon cementitious material suitable for low-carbon building materials is 700-800 m 2 / kg.

[0021] In the present application, under the premise of the lowest comprehensive energy consumption, the specific surface area of the ultra-fine material reaches 700-800 m 2When the ratio of the superfine low-carbon cementitious material to the cement is between 0.01 and 0.05 kg / kg, the hydration reaction speed of the system is relatively fast, and the strength and mechanical properties of the cementitious material can be significantly improved; the reason is that, with the increase of the specific surface area, the active substances such as silicon-aluminum oxides in the slag and fly ash are fully excited, and combined with the calcium hydroxide, ettringite and excess water generated during the hydration of cement to form C-S-H gel and calcium aluminum silicate which are beneficial to the strength growth of cement.

[0022] Compared with the prior art, the present application has the following technical effects:

[0023] (1) The superfine low-carbon cementitious material is obtained by mixing blast furnace slag powder and fly ash in a certain proportion and then performing superfine grinding, the obtained superfine low-carbon cementitious material can be combined with the cement hydration products to play a skeleton role, fill the gap between cement particles, improve the density of cement products, and then improve the strength and durability of cement; in particular, the superfine low-carbon cementitious material can replace about 10% of cement clinker when applied in cement, which can reduce the production cost of cement while reducing the emission of about 680 kg of carbon dioxide per ton of cement produced; when the superfine low-carbon cementitious material is used in concrete and its products, it can replace 60-100 kg of cement per cubic meter of concrete based on the national standard concrete ratio, which can reduce the hydration heat of cement, reduce the water demand of the concrete system, and alleviate the cracking problem of concrete and its products.

[0024] (2) The superfine low-carbon cementitious material is produced by scientific proportioning of industrial solid waste and using an open-circuit grinding system; when applied in cement production, it can reduce the amount of cement clinker, improve the strength of cement, and reduce the emission of carbon dioxide, becoming a low-carbon cement in name and in fact; it can also be applied in the production of concrete and its products to replace part of the cement, reduce production costs, improve the comprehensive performance of concrete and its products, and become a low-carbon concrete in name and in fact. Compared with ordinary cement admixtures and mineral admixtures, the superfine low-carbon cementitious material has high fineness, high activity and low water demand, and other excellent properties.

[0025] (3) The raw materials of the superfine low-carbon cementitious material are all from bulk industrial solid waste, and the cost is lower than that of traditional cement; at the same time, the industrial solid waste is fully utilized as a resource, and the occupation of land resources and the pollution of the environment are avoided. DETAILED DESCRIPTION

[0026] In the following, the technical solutions of the present application will be described in detail through specific examples, but it should be clear that these examples are used for illustration, but not to limit the scope of the present application.

[0027] Example 1

[0028] An ultra-fine low-carbon cementitious material suitable for low-carbon building materials, by weight parts, comprising: blast furnace slag powder 10 parts by weight, fly ash 10 parts by weight, activator 1 part by weight;

[0029] The specific surface area of the blast furnace slag powder is greater than 400 m 2 / kg, and the 28-day activity index is greater than 95%; the specific surface area of the fly ash is greater than 300 m 2 / kg, and the 28-day activity index is greater than 70%; the activator is triethanolamine.

[0030] The preparation method of the above-mentioned ultra-fine low-carbon cementitious material suitable for low-carbon building materials comprises: adding blast furnace slag powder, fly ash and activator according to the above-mentioned formula into a ball mill, and using an open-circuit grinding system for ultra-fine grinding, the grinding time is 35 min, to obtain the ultra-fine low-carbon cementitious material suitable for low-carbon building materials, the specific surface area of which is greater than 700 m 2 / kg.

[0031] Example 2

[0032] An ultra-fine low-carbon cementitious material suitable for low-carbon building materials, by weight parts, comprising: blast furnace slag powder 5 parts by weight, fly ash 20 parts by weight, activator 0.5 parts by weight;

[0033] The specific surface area of the blast furnace slag powder is greater than 400 m 2 / kg, and the 28-day activity index is greater than 95%; the specific surface area of the fly ash is greater than 300 m 2 / kg, and the 28-day activity index is greater than 70%; the activator is triethanolamine.

[0034] The preparation method of the above-mentioned ultra-fine low-carbon cementitious material suitable for low-carbon building materials comprises: adding blast furnace slag powder, fly ash and activator according to the above-mentioned formula into a ball mill, and using an open-circuit grinding system for ultra-fine grinding, the grinding time is 30 min, to obtain the ultra-fine low-carbon cementitious material suitable for low-carbon building materials, the specific surface area of which is greater than 700 m 2 / kg.

[0035] Example 3

[0036] An ultra-fine low-carbon cementitious material suitable for low-carbon building materials, by weight parts, comprising: blast furnace slag powder 20 parts by weight, fly ash 5 parts by weight, activator 3 parts by weight;

[0037] The specific surface area of the blast furnace slag powder is greater than 400 m 2 / kg, and the 28-day activity index is greater than 95%; the specific surface area of the fly ash is greater than 300 m 2 / kg, and the 28-day activity index is greater than 70%; the activator is triisopropanolamine.

[0038] The preparation method of the superfine low-carbon cementitious material suitable for low-carbon building materials comprises: adding blast furnace slag powder, fly ash and activator into a ball mill according to the above formula, and using an open circuit grinding system for superfine grinding, the grinding time is 40 min, and the superfine low-carbon cementitious material suitable for low-carbon building materials is obtained, and the specific surface area is greater than 700 m 2 / kg.

[0039] Example 4

[0040] A superfine low-carbon cementitious material suitable for low-carbon building materials, by weight, comprises: 10 parts by weight of blast furnace slag powder, 10 parts by weight of fly ash, and 1 part by weight of activator;

[0041] The specific surface area of the blast furnace slag powder is greater than 400 m 2 / kg, and the 28-day activity index is greater than 95%; the specific surface area of the fly ash is greater than 300 m 2 / kg, and the 28-day activity index is greater than 70%; the activator comprises triethanolamine and phosphonated silicate in a mass ratio of 1:12, and the phosphonated silicate is prepared by the following preparation method: adding montmorillonite into deionized water and stirring uniformly, heating to 70°C and constant temperature stirring for 1 h to obtain a suspension, then adding methacryloyloxyethyl trimethyl ammonium chloride, the mass ratio of methacryloyloxyethyl trimethyl ammonium chloride to montmorillonite is 1:10, after constant temperature stirring for 24 h at room temperature, filtering, washing with deionized water, and drying to obtain organic intercalated montmorillonite; the organic intercalated montmorillonite is added into water again and stirred uniformly, then vinyl phosphonic acid and benzoyl peroxide are added, the mass ratio of vinyl phosphonic acid, benzoyl peroxide and organic intercalated montmorillonite is 1:0.01:15, after heating to 80°C and constant temperature stirring for 5 h, filtering, washing with deionized water, and drying to obtain the phosphonated silicate.

[0042] The preparation method of the superfine low-carbon cementitious material suitable for low-carbon building materials comprises: adding blast furnace slag powder, fly ash and activator into a ball mill according to the above formula, and using an open circuit grinding system for superfine grinding, the grinding time is 40 min, and the superfine low-carbon cementitious material suitable for low-carbon building materials is obtained, and the specific surface area is greater than 700 m 2 / kg.

[0043] Comparative Example 1

[0044] A superfine low-carbon cementitious material suitable for low-carbon building materials, by weight, comprises: 10 parts by weight of blast furnace slag powder, 10 parts by weight of fly ash, and 1 part by weight of activator;

[0045] The specific surface area of the blast furnace slag powder is greater than 400 m 2 / kg, 28-day activity index greater than 95%; the fly ash has a specific surface area greater than 300 m 2 / kg, 28-day activity index greater than 70%; the activator is triethanolamine.

[0046] The preparation method of the above-mentioned ultra-fine low-carbon cementitious material suitable for low-carbon building materials comprises: adding blast furnace slag powder, fly ash and activator into a ball mill according to the above-mentioned formula, and performing ultra-fine grinding by using an open-circuit grinding system, wherein the grinding time is 35 min, so as to obtain the ultra-fine low-carbon cementitious material suitable for low-carbon building materials, which has a specific surface area greater than 700 m 2 / kg.

[0047] Comparative Example 2

[0048] An ultra-fine low-carbon cementitious material suitable for low-carbon building materials comprises, by weight fraction: 10 parts by weight of blast furnace slag powder, 10 parts by weight of fly ash, and 1 part by weight of activator.

[0049] The blast furnace slag powder has a specific surface area greater than 400 m 2 / kg, 28-day activity index greater than 95%; the fly ash has a specific surface area greater than 300 m 2 / kg, 28-day activity index greater than 70%; the activator is sodium silicate.

[0050] The preparation method of the above-mentioned ultra-fine low-carbon cementitious material suitable for low-carbon building materials comprises: adding blast furnace slag powder, fly ash and activator into a ball mill according to the above-mentioned formula, and performing ultra-fine grinding by using an open-circuit grinding system, wherein the grinding time is 35 min, so as to obtain the ultra-fine low-carbon cementitious material suitable for low-carbon building materials, which has a specific surface area greater than 700 m 2 / kg.

[0051] Experimental Example

[0052] The ultra-fine low-carbon cementitious materials obtained in the examples and comparative examples are mixed with comparative cement, standard sand and water to prepare test cement mortar: 9 parts by weight of ultra-fine low-carbon cementitious material, 51 parts by weight of comparative cement (ordinary portland cement with a strength grade of 42.5), 180 parts by weight of standard sand, and 30 parts by weight of water. The cement mortar is stirred according to GB / T17671, and the 3d and 28d flexural strength and compressive strength tests of the comparative mortar (without adding ultra-fine low-carbon cementitious material) and the test cement mortar are performed. The specific test results of the ultra-fine low-carbon cementitious materials obtained in the above-mentioned examples and comparative examples for the test cement mortar are shown in Table 1.

[0053] Table 1 Effect evaluation of the ultra-fine low-carbon cementitious materials obtained in the examples and comparative examples for the test cement mortar

[0054]

[0055]

[0056] As can be seen from Table 1, the compressive strength and flexural strength of the superfine low-carbon cementing material prepared in the embodiment of the application are both high, and the mechanical property is good; it is illustrated that, in the raw material ratio, while comprehensively considering the cost of raw materials, adding blast furnace slag powder and fly ash, the prepared cementing material has good comprehensive performance; the superfine low-carbon cementing material can effectively reduce the amount of cement clinker, improve the performance of cement, reduce the production cost of cement and reduce the emission of carbon dioxide by being directly mixed in about 15% in cement. Compared with reducing the proportion of blast furnace slag powder (comparative example 1), increasing the proportion of blast furnace slag powder (embodiment 1), the prepared cementing material has better comprehensive performance; compared with the inorganic alkali activator (comparative example 2), the prepared cementing material has better comprehensive performance by using the organic alkali activator (embodiment 1); in addition, the prepared cementing material has the best comprehensive performance (embodiment 4) by using the organic alkali and modified silicate as the activator.

[0057] The above merely provides the preferred embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art, according to the technical solution and the inventive concept of the present application, can make equivalent replacements or changes within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. An ultrafine low-carbon cementitious material suitable for low-carbon building materials, characterized in that, By weight, it includes: 5-20 parts by weight of blast furnace slag powder, 5-20 parts by weight of fly ash, and 0.5-3 parts by weight of activator; The activator comprises an organic base and a modified silicate; the weight ratio of the organic base to the modified silicate is 1:5-20. The organic base is triethanolamine and / or triisopropanolamine; the modified silicate is phosphonated silicate; The phosphonic silicate is obtained by organic intercalation modification of silicate with alkenyl ammonium salt, followed by copolymerization with alkenyl phosphonic acid. The alkenyl ammonium salt is at least one of acryloyloxyethyltrimethylammonium chloride, methacryloyloxyethyltrimethylammonium chloride, or trimethylvinylammonium bromide; the silicate is montmorillonite and / or soapstone; and the alkenyl phosphonic acid is at least one of vinylphosphonic acid, sodium vinylphosphonate, or potassium vinylphosphonate.

2. The ultrafine low-carbon cementitious material suitable for low-carbon building materials according to claim 1, characterized in that, The specific surface area of ​​the blast furnace slag powder is greater than 400 m². 2 / kg, with an activity index greater than 95% after 28 days.

3. The ultrafine low-carbon cementitious material suitable for low-carbon building materials according to claim 1 or 2, characterized in that, The specific surface area of ​​the fly ash is greater than 300 m². 2 / kg, with an activity index greater than 70% after 28 days.

4. A method for preparing an ultrafine low-carbon cementitious material suitable for low-carbon building materials as described in any one of claims 1-3, characterized in that, include: Blast furnace slag powder, fly ash and activator are added to a ball mill in parts by weight for ultrafine grinding to obtain the ultrafine low-carbon cementitious material suitable for low-carbon building materials.

5. The method for preparing ultrafine low-carbon cementitious materials suitable for low-carbon building materials according to claim 4, characterized in that, The ball mill adopts an open-circuit grinding system.

6. The method for preparing ultrafine low-carbon cementitious materials suitable for low-carbon building materials according to claim 4, characterized in that, The ultrafine grinding time is 30-40 minutes.

7. The method for preparing ultrafine low-carbon cementitious materials suitable for low-carbon building materials according to any one of claims 4-6, characterized in that, The specific surface area of ​​the ultrafine low-carbon cementitious material suitable for low-carbon building materials is 700-800 m². 2 / kg.

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