Modifier for regulating and controlling shrinkage of alkali-activated slag cementing material based on components, alkali-activated slag cementing material and preparation method of alkali-activated slag cementing material

Abstract

The invention provides a modifier for regulating and controlling shrinkage of an alkali-activated slag cementing material based on components, the alkali-activated slag cementing material and a preparation method of the alkali-activated slag cementing material, and belongs to the field of building materials. The invention provides a modifier for regulating and controlling shrinkage of an alkali-activated slag cementing material based on components, which comprises the following components in parts by mass: 0.5-5 parts of mineral powder; 0.5-4 parts of steel slag powder; 0.5 to 2.5 parts of desulfurized gypsum; and 0.1 to 0.5 part of expansive soil. According to the invention, the porosity of the test block is reduced by utilizing the micro-expansibility of the cementing material desulfurized gypsum and expansive soil and the hydration product C-S-(A)-H gel of the steel slag, so that the problem of large shrinkage of the alkali-activated slag material is solved. Meanwhile, SO4 < 2-> dissolved from the mineral powder and the desulfurized gypsum can induce the calcium-rich layer to quickly absorb water and dissolve, so that the alkali-activated slag cementing material is more compact in structure, and the bearing capacity and compressive strength of the alkali-activated slag cementing material are improved.

Description

Technical Field

[0001] The invention relates to the field of building materials, and in particular to a modifier for regulating the shrinkage of alkali-activated slag cementitious materials based on components, an alkali-activated slag cementitious material and a preparation method thereof. Background Art

[0002] Blast furnace slag is a by-product of the blast furnace ironmaking process and is the main component of industrial solid waste. The large-scale production and accumulation of blast furnace slag will not only cause environmental pollution and waste of resources, but also restrict the healthy development of the steel industry to a certain extent.

[0003] The development of alkali-activated slag cementitious materials is one of the effective ways to utilize excess slag resources. Alkali-activated slag cementitious materials are mainly a kind of low-carbon cementitious materials prepared by chemically reacting the potential activity of blast furnace slag with alkaline activators (such as sodium hydroxide, water glass, calcium carbonate, etc.) and other raw materials. Although alkali-activated slag cementitious materials have the advantages of high early strength, corrosion resistance, high temperature resistance, and low production energy consumption. However, alkali slag cementitious materials have the problems of poor toughness and large shrinkage. Summary of the invention

[0004] The present invention provides a modifier for regulating the shrinkage of alkali-activated slag cementitious materials based on components, an alkali-activated slag cementitious material and a preparation method thereof. The modifier of the present invention can improve the compressive strength of the alkali-activated slag cementitious materials and reduce the shrinkage of the cementitious materials.

[0005] The present invention provides a modifier for controlling the shrinkage of alkali-activated slag cementitious materials based on components, which comprises the following components by weight: 0.5 to 5 parts of mineral powder; 0.5 to 4 parts of steel slag powder; 0.5 to 2.5 parts of desulfurized gypsum; and 0.1 to 0.5 parts of expansive soil.

[0006] Preferably, the specific surface area of ​​the mineral powder is 400-480m 2 kg -1 ;

[0007] In terms of mass fraction, the mineral powder includes SiO 2 29.557~32.869%,Fe 2 O 3 0.262~0.274%, MgO8.542~9.662%, Al 2 O 3 17.873~21.557%, CaO 34.581~36.223%, K 2 O0.26~0.4%、Na 2 O 0.53~0.73%, MnO 0.09~0.16%, others 2.979~3.451%.

[0008] Preferably, the specific surface area of ​​the steel slag powder is 410-470 m 2 kg -1 ;

[0009] In terms of mass fraction, the steel slag powder includes SiO 2 11.26~13.95%,Fe 2 O 3 12.11~15.52%, MgO3.93~5.01%, Al 2 O 3 8.76~10.26%, CaO 46.21~48.08%, K 2 O 0.14~0.23%, Cl 0.397~0.554%, Na 2 O 0.779~0.850%, MnO 1.75~1.87%, F 0.227~0.348%, SO 3 2.97~4.05%, others 5.159~5.586%.

[0010] Preferably, the specific surface area of ​​the desulfurized gypsum is 350 to 400 m 2 kg -1 ;

[0011] In terms of mass fraction, the desulfurized gypsum includes: SiO 2 11.23~15.77%,Fe 2 O 3 0.09~0.11%, MgO2.52~2.58%, Al 2 O 3 1.42~1.77%, CaO 38.55~41.27%, P 2 O 5 0.04~0.11%、K 2 O0.07~0.16%、Na 2 O 0.5~0.72%, MnO 0.05~0.08%, TiO 2 0.02~0.03%, S28.47~32.92%, SO 3 8.92~12.13%, others 0.13~0.34%.

[0012] Preferably, the liquid limit of the expansive soil is 44.2-46.4%, the plastic limit is 16.5-18.5%, the plasticity index is 20.5-23.4, the free expansion rate is 44.2-46.4%, the shrinkage limit is 13.1-14.5%, and the water content is 16.8-18.5%.

[0013] The present invention also provides an alkali-activated slag cementitious material, which comprises the following raw materials by weight:

[0014]

[0015] The modifier includes the modifier according to any one of claims 1 to 5.

[0016] Preferably, the specific surface area of ​​the blast furnace slag is 450 to 486 m 2 kg -1 ;

[0017] In terms of mass fraction, the blast furnace slag comprises: SiO 2 31.22~33.58%,Fe 2 O 3 0.03~0.07%, MgO7.54~8.99%, Al 2 O 3 8.72~10.95%, CaO 42.75~44.02%, P 2 O 5 0.02~0.04%、K 2 O 0.4~0.72%、Na 2 O 0.35~0.72%, MnO 0.29~0.44%, TiO 2 0.65~0.92%, S1.37~2.22%, others 1.62~2.37%.

[0018] Preferably, the modulus of the alkali-activated solution is 1 to 1.4.

[0019] The present invention also provides a method for preparing the alkali-activated slag cementitious material according to the above technical solution, comprising the following steps:

[0020] The blast furnace slag, alkali activated solution, water and a modifier are mixed, then molded and cured to obtain the alkali activated slag cementitious material.

[0021] Preferably, the curing includes room temperature curing and standard curing;

[0022] The normal temperature curing time is 1 day;

[0023] The humidity during the standard curing is 95% and the temperature is 20±2°C.

[0024] In the present invention, the steel slag powder in the component of the modifier for regulating the shrinkage of alkali-activated slag cementitious materials based on the components can provide the Ca2+ lacking in the hydration process of the alkali-activated slag cementitious materials. 2+, generating CS-(A)-H gel, reducing the porosity of alkali-activated slag cementitious materials, and facilitating the development of drying shrinkage of alkali-activated slag cementitious materials. The hydration products of desulfurized gypsum, dihydrate gypsum and calcium aluminate, have a certain micro-expansion, reducing the shrinkage and deformation of alkali-activated slag cementitious materials. At the same time, SO dissolved from mineral powder and desulfurized gypsum 4 2- It can induce the calcium-rich layer (the calcium-rich layer will hinder the accumulation of components, thereby limiting the radial growth and axial growth of CS-(A)-H gel) to absorb water and dissolve rapidly, making the structure of alkali-activated slag cementitious materials denser, thereby improving the bearing capacity and compressive strength of alkali-activated slag cementitious materials. Expansive soil is cheap, and the easily swellable mineral components (montmorillonite and illite) have certain water absorption and expansion properties, which can reduce the shrinkage and expansion rate of alkali-activated slag cementitious materials and improve their anti-shrinkage performance.

[0025] The present invention effectively utilizes solid wastes such as desulfurized gypsum, steel slag powder, expanded soil and blast furnace slag, reduces the demand for natural resources, generates great economic and social benefits, and is conducive to sustainable development and environmental protection.

[0026] The present invention utilizes desulfurized gypsum with micro-expansion and expansive soil to improve the shrinkage performance of alkali-activated slag cementitious materials, reduce the development of cracks, and effectively improve the working performance of alkali-activated slag cementitious materials.

[0027] In summary, in order to solve the problem of poor toughness and large shrinkage of alkali-activated slag materials, the present invention uses the cementitious material desulfurized gypsum, the micro-expansion of expansive soil, and the hydration product of steel slag CS-(A)-H gel to reduce the porosity of the test block, thereby solving the problem of large shrinkage of alkali-activated slag materials. 4 2- It can induce the calcium-rich layer to absorb water and dissolve rapidly, making the structure of the alkali-activated slag cementitious material more compact, thereby improving the bearing capacity and compressive strength of the alkali-activated slag cementitious material. Compared with the existing shrinkage modifiers, the innovation of the present invention is that the proposed shrinkage modifier introduces the micro-expansion of desulfurized gypsum into the alkaline slag material environment for the first time on the basis of all solid waste, and is used to solve the shrinkage problem. It meets the requirements of the national sustainable development concept, which is also of great practical significance for the development of the construction industry and the protection of the ecological environment. DETAILED DESCRIPTION

[0028] The present invention provides a modifier for controlling the shrinkage of alkali-induced slag cementitious materials based on components, which comprises the following components in parts by mass:

[0029]

[0030]

[0031] In terms of mass fraction, the modifier provided by the present invention includes 0.5 to 3 parts of mineral powder. In a specific embodiment of the present invention, the mass fraction of the mineral powder in the modifier can be 0.5, 1, 1.5, 2, 2.5 or 3 parts; the specific surface area of ​​the mineral powder is preferably 400 to 480 m 2 kg -1 In a specific embodiment of the present invention, the specific surface area of ​​the mineral powder can be 400m 2 kg -1 、410m 2 kg -1 、420m 2 kg -1 、430m 2 kg -1 、450m 2 kg -1 、460m 2 kg -1 、470m 2 kg -1 or 480m 2 kg -1 ;

[0032] In the present invention, the mineral powder preferably comprises SiO 2 29.557~32.869%,Fe 2 O 3 0.262~0.274%, MgO8.542~9.662%, Al 2 O 3 17.873~21.557%, CaO34.581~36.223%, K 2 O 0.26~0.4%、Na 2 O 0.53-0.73%, MnO 0.09-0.16%, others 2.979-3.451%; in terms of mass fraction, the mineral powder more preferably includes SiO 2 30~31%,Fe 2 O 3 0.265~0.27%, MgO9~9.5%, Al 2 O 3 18~19%, CaO35~35.5%, K 2 O0.3~0.35%、Na 2 O 0.6~0.7%, MnO 0.12~0.15%, others 3~3.3%.

[0033] Based on the mass fraction of the mineral powder, the modifier provided by the present invention includes 0.5 to 4 parts of steel slag powder. In a specific embodiment of the present invention, the mass fraction of steel slag powder in the modifier can be 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 3.8 or 4 parts; the specific surface area of ​​the steel slag powder is preferably 410 to 470 m 2 kg -1 In a specific embodiment of the present invention, the specific surface area of ​​the steel slag powder can be 410m 2 kg -1 、420m 2 kg -1 、430m 2 kg -1 、450m 2 kg -1 、460m 2 kg -1 、462m 2 kg -1 or 470m 2 kg -1 .

[0034] In terms of mass fraction, the steel slag powder preferably comprises SiO 2 11.26~13.95%,Fe 2 O 3 12.11~15.52%, MgO3.93~5.01%, Al 2 O 3 8.76~10.26%, CaO46.21~48.08%, K 2 O0.14~0.23%, Cl0.397~0.554%, Na 2 O 0.779~0.850%, MnO 1.75~1.87%, F0.227~0.348%, SO 3 2.97-4.05%, and the rest 5.159-5.586%; in terms of mass fraction, the steel slag powder more preferably includes SiO 2 12~13%, Fe 2 O 3 13~15%, MgO4~4.5%, Al 2 O 3 9~10%, CaO46.5~48%, K 2 O 0.15~0.2%, Cl 0.5~0.55%, Na 2 O 0.8~0.840%, MnO 1.8~1.85%, F 0.25~0.3%, SO 3 3~3.5%, others 5.3~5.5%.

[0035] Based on the mass fraction of the mineral powder, the modifier provided by the present invention includes 0.5 to 2.5 parts of desulfurized gypsum. In a specific embodiment of the present invention, the mass fraction of desulfurized gypsum in the modifier can be 0.5, 0.6, 1.5, 1.8 or 2.5 parts; the specific surface area of ​​the desulfurized gypsum is preferably 350 to 400 m 2 kg -1 In a specific embodiment of the present invention, the specific surface area of ​​the desulfurized gypsum can be 350m 2 kg -1 、 360m 2 kg -1 、 370m 2 kg -1 、 380m 2 kg -1 、 390m 2 kg -1 or 400m 2 kg -1 ;

[0036] In terms of mass fraction, the desulfurized gypsum preferably comprises: SiO 2 11.23~15.77%,Fe 2 O 3 0.09~0.11%, MgO2.52~2.58%, Al 2 O 3 1.42~1.77%, CaO38.55~41.27%, P 2 O 5 0.04~0.11%、K 2 O0.07~0.16%、Na 2 O 0.5~0.72%, MnO 0.05~0.08%, TiO 2 0.02~0.03%, S28.47~32.92%, SO 3 8.92-12.13%, and other 0.13-0.34%; in terms of mass fraction, the desulfurized gypsum more preferably includes: SiO 2 12~13%,Fe 2 O 3 0.1%, MgO2.54~2.55%, Al 2 O 3 1.5~1.7%, CaO 39~40%, P 2 O 5 0.05~0.08%、K 2 O 0.1~0.12%、Na 2 O 0.6~0.7%, MnO 0.06~0.07%, S29~30%, SO 3 9~11%, others 0.2~0.3%.

[0037] Based on the mass fraction of the mineral powder, the modifier provided by the present invention includes 0.1 to 0.5 parts of expansive soil. In a specific embodiment of the present invention, the mass fraction of expansive soil in the modifier can be 0.1 parts, 0.12 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.45 parts, 0.48 parts or 0.5 parts.

[0038] In the present invention, the liquid limit of the expansive soil is preferably 44.2-46.4%, the plastic limit is preferably 16.5-18.5%, the plasticity index is preferably 20.5-23.4, the free expansion rate is preferably 44.2-46.4%, the shrinkage limit is preferably 13.1-14.5%, and the moisture content is preferably 16.8-18.5%.

[0039] The present invention also provides an alkali-activated slag cementitious material, which comprises the following raw materials by weight:

[0040]

[0041] The modifier is the modifier described in the above technical solution.

[0042] In the present invention, the raw material for preparing the alkali-activated slag cementitious material includes 60 to 90 parts by weight of blast furnace slag. In a specific embodiment of the present invention, the mass fraction of blast furnace slag in the raw material for preparing the alkali-activated slag cementitious material can be 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, 95 parts or 100 parts; the specific surface area of ​​the blast furnace slag is preferably 450 to 486 m 2 kg -1 In a specific embodiment of the present invention, the specific surface area of ​​the blast furnace slag can be 450m 2 kg -1 、460m 2 kg -1 、470m 2 kg -1 、480m 2 kg -1 or 486m 2 kg -1 ;

[0043] In terms of mass fraction, the blast furnace slag preferably comprises: SiO 2 31.22~33.58%,Fe 2 O 3 0.03~0.07%, MgO7.54~8.99%, Al 2 O 3 8.72~10.95%, CaO42.75~44.02%, P 2 O 5 0.02~0.04%、K 2 O 0.4~0.72%、Na 2 O 0.35~0.72%, MnO 0.29~0.44%, TiO 2 0.65～0.92％，S1.37～ 2.22%, others 1.62-2.37%; in terms of mass fraction, the blast furnace slag is more Preferred includes: SiO 2 32~33%,Fe 2 O 3 0.04~0.05%, MgO8~8.5%, Al 2 O 3 9~10%、CaO43~44%、P 2 O 5 0.03%、K 2 O 0.5~0.6%、Na 2 O 0.4~0.6%, MnO 0.3~0.4%, TiO 2 0.7~0.8%, S1.6~2%, others 1.9~2%.

[0044] Based on the mass fraction of the blast furnace slag, the raw materials for preparing the alkali-activated slag cementitious material provided by the present invention include 16 to 52 parts of alkali-activated solution. In a specific embodiment of the present invention, the mass fraction of the alkali-activated solution in the raw materials for preparing the alkali-activated slag cementitious material can be 16 parts, 20 parts, 25 parts, 30 parts, 35 parts, 70 parts or 50 parts; the modulus of the alkali-activated solution is preferably 1 to 1.4. In a specific embodiment of the present invention, the modulus of the alkali-activated solution can be 1, 1.2 or 1.4.

[0045] In the present invention, the method for preparing the alkaline activator solution preferably comprises: mixing water glass and NaOH and then allowing the mixture to stand to obtain the alkaline activator solution.

[0046] In the present invention, the modulus of the water glass is preferably 3.22, the water content is preferably 64 wt %; and the standing time is preferably 1 day.

[0047] Based on the mass fraction of the blast furnace slag, the raw materials for preparing the alkali-activated slag cementitious material include 21 to 39 parts of water. In a specific embodiment of the present invention, the mass fraction of water in the raw materials for preparing the alkali-activated slag cementitious material can be 21 parts, 25 parts, 30 parts, 35 parts or 39 parts.

[0048] Based on the mass fraction of the blast furnace slag, the raw materials for preparing the alkali-activated slag cementitious material include 5 to 12 parts of modifier. In a specific embodiment of the present invention, the mass fraction of the modifier in the raw materials for preparing the alkali-activated slag cementitious material can be 5 parts, 5.5 parts, 6 parts, 10 parts or 11 parts.

[0049] The present invention also provides a method for preparing the alkali-activated slag cementitious material according to the above technical solution, comprising the following steps:

[0050] The raw materials for preparing the alkali-activated slag cementitious material are mixed, molded and cured to obtain the alkali-activated slag cementitious material.

[0051] In the present invention, the step of injecting the slurry obtained after mixing into a mold is preferably included before the molding.

[0052] In the present invention, the mixing preferably comprises: mixing blast furnace slag and a modifier and then mixing with an alkali activator solution and water.

[0053] In the present invention, the time of room temperature curing is preferably 1 day;

[0054] After the room temperature curing and before the standard curing, the mold is preferably opened to demould the obtained test piece.

[0055] In the present invention, the humidity of the standard curing is preferably 95%, and the temperature is preferably 20±2°C.

[0056] The modifier for controlling the shrinkage of alkali-activated slag cementitious materials based on components, the alkali-activated slag cementitious materials and the preparation method thereof provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0057] In the embodiment:

[0058] The specific surface area of ​​desulfurized gypsum is 360m 2 kg -1 ;

[0059] In terms of mass fraction, the components of the desulfurized gypsum are: SiO 2 15.77%, Fe 2 O 3 0.11%, MgO2.58%, Al 2 O 3 1.42%, CaO 38.55%, P 2 O 5 0.11%, K 2 O 0.16%, Na 2 O 0.5%, MnO 0.05%, TiO 2 0.02%, S28.47%, SO3 12.13%, others 0.13%.

[0060] The specific surface area of ​​blast furnace slag is 480m 2 kg -1 ;

[0061] In terms of mass fraction, the components of the blast furnace slag are: SiO 2 33.58%, Fe 2 O 3 0.03%, MgO7.54%, Al 2 O 3 8.72%, CaO 44.02%, P 2 O 5 0.04%、K 2 O 0.4%, Na 2 O 0.72%, MnO 0.29%, TiO 2 0.92%, S1.37%, others 2.37%.

[0062] The specific surface area of ​​steel slag powder is 438m 2 kg -1 ;

[0063] In terms of mass fraction, the components of steel slag powder are: SiO 2 13.95%, Fe 2 O 3 12.11%, MgO 5.01%, Al 2 O 3 8.76%, CaO 48.08%, K 2 O 0.14%, Cl 0.397%, Na 2 O 0.779%, MnO 1.87%, F 0.348%, SO3 2.97%, others 5.586%.

[0064] The specific surface area of ​​the mineral powder is 460m 2 kg -1 ;

[0065] In terms of mass fraction, the mineral powder comprises: SiO 2 32.869%, Fe 2 O 3 0.274%, MgO9.662%, Al 2 O 3 17.873%, CaO 34.581%, K 2 O 0.4%, Na 2 O 0.73%, MnO 0.16%, others 3.451%.

[0066] The liquid limit of expansive soil is 46.4%, plastic limit is 18.5%, plasticity index is 23.4, free expansion rate is 46.4%, shrinkage limit is 14.5%, and water content is 16.8%.

[0067] The preparation method of the alkali-activated slag cementitious material in the embodiment is:

[0068] 1) At room temperature and pressure, add alkali activator solution and water to the uniformly mixed powder, stir evenly to obtain alkali-activated slag cementitious material slurry, stir for 1 minute, inject into a mold for vibration molding and cure at room temperature, demould after 1 day, and obtain alkali-activated slag cementitious material slurry specimen (length, width and height are 160*40*40 (mm) respectively);

[0069] 2) The test piece is subjected to standard curing at a humidity of 95% and a temperature of 20±2° C. to obtain the alkali-activated slag cementitious material.

[0070] Example 1

[0071] First, industrial water glass (water content 64 wt%) with a modulus n of 3.22 was mixed with chemically pure NaOH and stirred at room temperature to prepare an alkali-activated solution with a modulus of 1.2. The solution was allowed to stand for one day before use.

[0072] According to the weight fraction, 95 parts of blast furnace slag powder, 40 parts of alkali-activated solution, 30 parts of water, and 5.7 parts of modifier (2.5 parts of mineral powder, 2.5 parts of steel slag powder, 0.5 parts of desulfurized gypsum, and 0.2 parts of expansive soil) were weighed to prepare an alkali-activated slag cementitious material after mixing in this proportion. The performance of the alkali-activated slag cementitious material was tested and compared with the performance of the alkali-activated slag cementitious material prepared without adding the modifier (the rest is the same as Example 1). The results of the performance are shown in Table 1.

[0073] Example 2

[0074] First, industrial water glass (water content 64 wt%) with a modulus n of 3.22 was mixed with chemically pure NaOH, stirred at room temperature to prepare an alkali-activated solution with a modulus of 1.0, and the solution was allowed to stand for one day before use.

[0075] 95 parts of blast furnace slag powder, 40 parts of alkali-activated solution, 30 parts of water, and 6.6 parts of modifier (3.5 parts of mineral powder, 2.5 parts of steel slag powder, 0.5 parts of desulfurized gypsum, and 0.1 parts of expansive soil) were weighed according to weight fractions, and an alkali-activated slag cementitious material was prepared by mixing them in this proportion. The properties of the alkali-activated slag cementitious material were tested, and the results were compared with the properties of the alkali-activated slag cementitious material prepared without adding the modifier (the rest is the same as Example 2), and the results are shown in Table 1.

[0076] Example 3

[0077] First, industrial water glass (water content 64 wt%) with a modulus n of 3.22 was mixed with chemically pure NaOH and stirred at room temperature to prepare an alkali-activated solution with a modulus of 1.4. The solution was allowed to stand for one day before use.

[0078] 95 parts of blast furnace slag powder, 40 parts of alkali-activated solution, 30 parts of water, and 9 parts of modifier (3.5 parts of mineral powder, 3.0 parts of steel slag powder, 2.0 parts of desulfurized gypsum, and 0.5 parts of expansive soil) were weighed according to weight fractions, and an alkali-activated slag cementitious material was prepared by mixing them in this proportion. The properties of the alkali-activated slag cementitious material were tested, and the results were compared with the properties of the alkali-activated slag cementitious material prepared without adding the modifier (the rest are the same as Example 3), and the results are shown in Table 1.

[0079] Example 4

[0080] First, industrial water glass (water content 64 wt%) with a modulus n of 3.22 was mixed with chemically pure NaOH and stirred at room temperature to prepare an alkali-activated solution with a modulus of 1.2. The solution was allowed to stand for one day before use.

[0081] 90 parts of blast furnace slag powder, 32 parts of alkali-activated solution, 30 parts of water, and 7.5 parts of modifier (4.0 parts of mineral powder, 2.0 parts of steel slag powder, 1 part of desulfurized gypsum, and 0.5 parts of expansive soil) were weighed according to weight fractions, and an alkali-activated slag cementitious material was prepared by mixing them in this proportion. The properties of the alkali-activated slag cementitious material were tested, and the results were compared with the properties of the alkali-activated slag cementitious material prepared without adding the modifier (the rest are the same as Example 4), and the results are shown in Table 1.

[0082] Example 5

[0083] First, industrial water glass (water content 64 wt%) with a modulus n of 3.22 was mixed with chemically pure NaOH and stirred at room temperature to prepare an alkali-activated solution with a modulus of 1.2. The solution was allowed to stand for one day before use.

[0084] 85 parts of blast furnace slag powder, 32 parts of alkali-activated solution, 30 parts of water, and 8.5 parts of modifier (4.5 parts of mineral powder, 2.0 parts of steel slag powder, 1.5 parts of desulfurized gypsum, and 0.5 parts of expansive soil) were weighed according to weight fractions. The alkali-activated slag cementitious material prepared by mixing in this ratio was tested. The properties of the alkali-activated slag cementitious material prepared without adding the modifier (the rest are the same as Example 5) are shown in Table 1.

[0085] Example 6

[0086] First, industrial water glass (water content 64 wt%) with a modulus n of 3.22 was mixed with chemically pure NaOH and stirred at room temperature to prepare an alkali-activated solution with a modulus of 1.2. The solution was allowed to stand for one day before use.

[0087] 80 parts of blast furnace slag powder, 24 parts of alkali-activated solution, 30 parts of water, and 9.8 parts of modifier (5.0 parts of mineral powder, 2.5 parts of steel slag powder, 2.0 parts of desulfurized gypsum, and 0.3 parts of expansive soil) were weighed according to weight fractions, and an alkali-activated slag cementitious material was prepared by mixing them in this proportion. The performance of the alkali-activated slag cementitious material was tested compared with that of the alkali-activated slag cementitious material prepared without adding the modifier (the rest is the same as Example 6), and the results are shown in Table 1.

[0088] Example 7

[0089] First, industrial water glass (water content 64 wt%) with a modulus n of 3.22 was mixed with chemically pure NaOH and stirred at room temperature to prepare an alkali-activated solution with a modulus of 1.2. The solution was allowed to stand for one day before use.

[0090] 75 parts of blast furnace slag powder, 32 parts of alkali-activated solution, 30 parts of water, and 10.5 parts of modifier (5.0 parts of mineral powder, 3.5 parts of steel slag powder, 2.5 parts of desulfurized gypsum, and 0.5 parts of expansive soil) were weighed according to weight fractions, and an alkali-activated slag cementitious material was prepared by mixing them in this proportion. The performance of the alkali-activated slag cementitious material was tested compared with that of the alkali-activated slag cementitious material prepared without adding the modifier (the rest is the same as Example 7), and the results are shown in Table 1.

[0091] Example 8

[0092] First, industrial water glass (water content 64 wt%) with a modulus n of 3.22 was mixed with chemically pure NaOH and stirred at room temperature to prepare an alkali-activated solution with a modulus of 1.2. The solution was allowed to stand for one day before use.

[0093] 80 parts of blast furnace slag powder, 32 parts of alkali-activated solution, 30 parts of water, and 10 parts of modifier (4.3 parts of mineral powder, 3.3 parts of steel slag powder, 2.0 parts of desulfurized gypsum, and 0.4 parts of expansive soil) were weighed according to weight fractions, and an alkali-activated slag cementitious material was prepared by mixing them in this proportion. The performance of the alkali-activated slag cementitious material was tested compared with that of the alkali-activated slag cementitious material prepared without adding the modifier (the rest is the same as Example 8), and the results are shown in Table 1.

[0094] Example 9

[0095] First, industrial water glass (water content 64 wt%) with a modulus n of 3.22 was mixed with chemically pure NaOH and stirred at room temperature to prepare an alkali-activated solution with a modulus of 1.2. The solution was allowed to stand for one day before use.

[0096] 100 parts of blast furnace slag powder, 40 parts of alkali-activated solution, 30 parts of water, and 11.9 parts of modifier (5.0 parts of mineral powder, 4.0 parts of steel slag powder, 2.5 parts of desulfurized gypsum, and 0.4 parts of expansive soil) were weighed according to weight fractions. The alkali-activated slag cementitious material was prepared by mixing them in this proportion. The performance of the alkali-activated slag cementitious material was tested and compared with the performance of the alkali-activated slag cementitious material prepared without adding the modifier (the rest is the same as Example 9), and the results are shown in Table 1.

[0097] Comparative Example 1

[0098] First, industrial water glass (water content 64 wt%) with a modulus n of 3.22 was mixed with chemically pure NaOH and stirred at room temperature to prepare an alkali-activated solution with a modulus of 1.2. The solution was allowed to stand for one day before use.

[0099] 100 parts of blast furnace slag powder, 40 parts of alkali-activated solution, 30 parts of water, and 11.9 parts of modifier (6.9 parts of steel slag powder, 4.3 parts of desulfurized gypsum, and 0.4 parts of expansive soil) were weighed according to weight fractions. The alkali-activated slag cementitious material was prepared by mixing them in this proportion. The performance of the alkali-activated slag cementitious material was tested and compared with the performance of the alkali-activated slag cementitious material prepared without adding the modifier (the rest is the same as that of Comparative Example 1), and the results are shown in Table 1.

[0100] Comparative Example 2

[0101] First, industrial water glass (water content 64 wt%) with a modulus n of 3.22 was mixed with chemically pure NaOH and stirred at room temperature to prepare an alkali-activated solution with a modulus of 1.2. The solution was allowed to stand for one day before use.

[0102] 100 parts of blast furnace slag powder, 40 parts of alkali-activated solution, 30 parts of water, and 11.9 parts of modifier (7.5 parts of mineral powder, 3.8 parts of desulfurized gypsum, and 0.6 parts of expansive soil) were weighed according to weight fractions. The alkali-activated slag cementitious material was prepared by mixing them in this proportion. The performance of the alkali-activated slag cementitious material was tested and compared with the performance of the alkali-activated slag cementitious material prepared without adding the modifier (the rest is the same as that of Comparative Example 2), and the results are shown in Table 1.

[0103] Comparative Example 3

[0104] First, industrial water glass (water content 64 wt%) with a modulus n of 3.22 was mixed with chemically pure NaOH and stirred at room temperature to prepare an alkali-activated solution with a modulus of 1.2. The solution was allowed to stand for one day before use.

[0105] 100 parts of blast furnace slag powder, 40 parts of alkali-activated solution, 30 parts of water, and 11.9 parts of modifier (6.3 parts of mineral powder, 5.0 parts of steel slag powder, and 0.6 parts of expansive soil) were weighed according to weight fractions. The alkali-activated slag cementitious material was prepared by mixing them in this proportion. The performance of the alkali-activated slag cementitious material was tested and compared with the performance of the alkali-activated slag cementitious material prepared without adding the modifier (the rest is the same as Comparative Example 3), and the results are shown in Table 1.

[0106] Comparative Example 4

[0107] First, industrial water glass (water content 64 wt%) with a modulus n of 3.22 was mixed with chemically pure NaOH and stirred at room temperature to prepare an alkali-activated solution with a modulus of 1.2. The solution was allowed to stand for one day before use.

[0108] 100 parts of blast furnace slag powder, 40 parts of alkali-activated solution, 30 parts of water, and 11.9 parts of modifier (5.2 parts of mineral powder, 4.1 parts of steel slag powder, and 2.6 parts of desulfurized gypsum) were weighed according to weight fractions. The alkali-activated slag cementitious material was prepared by mixing them in this proportion. The performance of the alkali-activated slag cementitious material was tested and compared with the performance of the alkali-activated slag cementitious material prepared without adding the modifier (the rest is the same as Comparative Example 4), and the results are shown in Table 1.

[0109] According to the "Technical Process for Application of Solid Waste-based Cementitious Materials" (T / CECS689-2020), the performance tests were carried out on the alkali-activated slag cementitious materials prepared in the above-mentioned Example 1, Example 2, Example 3, Example 4, Example 5, Example 6, Example 7, Example 8, Example 9, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4.

[0110] The performance indicators of the masonry mortar prepared according to the embodiment are shown in Table 1.

[0111] Table 1 Performance test results of each embodiment

[0112]

[0113]

[0114] From the data in Table 1, it can be seen that after adding the modifier to the alkali-activated slag cementitious material, the shrinkage and expansion rate of the alkali-activated slag cementitious material is improved to a certain extent, and the working performance is enhanced, that is, the addition of the modifier significantly improves the shrinkage performance of the activated slag cementitious material. At the same time, after adding the modifier to the alkali-activated slag cementitious material, the compressive and flexural strengths of the alkali-activated slag cementitious material are improved to a certain extent. In the present invention, the modifier optimizes the working performance of the cementitious material, reduces the development of cracks, enhances the flexural mechanical properties, and effectively increases the application field of the alkali-activated slag cementitious material because of the addition of the desulfurized gypsum with micro-expansion.

[0115] At the same time, by comparing Example 1 with Example 9, it can be seen that although the modifier without mineral powder can better improve the shrinkage performance of the material, it loses certain mechanical properties, resulting in a decrease in overall compressive and flexural strength. By comparing Example 2 with Example 9, it can be seen that the modifier without steel slag powder has a decreased efficiency in improving the shrinkage and mechanical properties of the material. By comparing Example 3 with Example 9, it can be seen that although the modifier without desulfurized gypsum can better improve the mechanical properties of the material, the material has a greater decrease in shrinkage performance optimization efficiency. By comparing Example 4 with Example 9, it can be seen that the modifier without expansive soil has a certain decrease in improving the shrinkage performance of the material. Therefore, the components of the modifier of the present invention are 0.5 to 5 parts of mineral powder; 0.5 to 4 parts of steel slag powder; 0.5 to 2.5 parts of desulfurized gypsum; 0.1 to 0.5 parts of expansive soil.

[0116] In summary, applying the modifier of the present invention to alkali-activated slag cementitious materials can effectively improve the shrinkage performance, toughness and bearing capacity of the cementitious materials, while reducing the demand for natural resources, which is beneficial to sustainable development and environmental protection.

[0117] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A modifier for shrinkage of alkali-induced slag cementitious materials based on component regulation, characterized in that: In parts by mass, it includes the following components:

2. The modifier according to claim 1, characterized in that The specific surface area of ​​the mineral powder is 400-480m 2 kg -1 ; In terms of mass fraction, the mineral powder includes SiO2 29.557-32.869%, Fe2O3 0.262-0.274%, MgO 8.542-9.662%, Al2O3 17.873-21.557%, CaO 34.581-36.223%, K2O 0.26-0.4%, Na2O 0.53-0.73%, MnO 0.09-0.16%, and others 2.979-3.451%.

3. The modifier according to claim 1, characterized in that The specific surface area of ​​the steel slag powder is 410-470m 2 kg -1 ; Calculated by mass fraction, the steel slag powder includes SiO2 11.26-13.95%, Fe2O3 12.11-15.52%, MgO 3.93-5.01%, Al2O3 8.76-10.26%, CaO 46.21-48.08%, K2O 0.14-0.23%, Cl 0.397-0.554%, Na2O 0.779-0.850%, MnO 1.75-1.87%, F 0.227-0.348%, SO3 2.97-4.05%, and others 5.159-5.586%.

4. The modifier according to claim 1, characterized in that The specific surface area of ​​the desulfurized gypsum is 350-400m 2 kg -1 ; Calculated by mass fraction, the desulfurized gypsum includes: SiO2 11.23-15.77%, Fe2O3 0.09-0.11%, MgO 2.52-2.58%, Al2O3 1.42-1.77%, CaO 38.55-41.27%, P2O5 0.04-0.11%, K2O 0.07-0.16%, Na2O 0.5-0.72%, MnO 0.05-0.08%, TiO2 0.02-0.03%, S2 8.47-32.92%, SO3 8.92-12.13%, and others 0.13-0.34%.

5. The modifier according to claim 1, characterized in that The expansive soil has a liquid limit of 44.2-46.4%, a plastic limit of 16.5-18.5%, a plasticity index of 20.5-23.4, a free expansion rate of 44.2-46.4%, a shrinkage limit of 13.1-14.5%, and a water content of 16.8-18.5%.

6. An alkali-activated slag cementitious material, characterized in that: The preparation includes the following raw materials by weight: The modifier includes the modifier according to any one of claims 1 to 5.

7. The alkali-activated slag cementitious material according to claim 6, characterized in that: The specific surface area of ​​the blast furnace slag is 450 to 486 m 2 kg -1 ; Calculated by mass fraction, the blast furnace slag includes: SiO231.22-33.58%, Fe2O30.03-0.07%, MgO7.54-8.99%, Al2O38.72-10.95%, CaO 42.75-44.02%, P2O50.02-0.04%, K2O 0.4-0.72%, Na2O 0.35-0.72%, MnO 0.29-0.44%, TiO20.65-0.92%, S1.37-2.22%, and others 1.62-2.37%.

8. The alkali-activated slag cementitious material according to claim 6, characterized in that: The modulus of the alkali-activated solution is 1 to 1.

4.

9. The method for preparing the alkali-activated slag cementitious material according to any one of claims 6 to 8, characterized in that: The following steps are involved: The blast furnace slag, alkali activated solution, water and a modifier are mixed, then molded and cured to obtain the alkali activated slag cementitious material.

10. The preparation method according to claim 9, characterized in that: The curing includes normal temperature curing and standard curing; The normal temperature curing time is 1 day; The humidity during the standard curing is 95% and the temperature is 20±2°C.

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