CN120097648A - A modifier for controlling shrinkage of alkali-activated slag cementitious material based on components, alkali-activated slag cementitious material and preparation method thereof - Google Patents

Abstract

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, and belongs to the field of building materials. The present invention provides a modifier for regulating the shrinkage of alkali-activated slag cementitious materials based on components, which comprises the following components by mass: 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. The present invention utilizes the micro-expansion of desulfurized gypsum, expansive soil, and the hydration product C-S-(A)-H gel of steel slag to reduce the porosity of the test block, thereby solving the problem of large shrinkage of alkali-activated slag materials. At the same time, SO ₄ ^2- dissolved from mineral powder and desulfurized gypsum can induce the calcium-rich layer to absorb water and dissolve rapidly, making the structure of the alkali-activated slag cementitious material denser, thereby improving the bearing capacity and compressive strength of the alkali-activated slag cementitious material.

Description

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

Technical Field

The invention relates to the field of building materials, in particular to a modifier for regulating and controlling shrinkage of alkali-activated slag cementing material based on components, the alkali-activated slag cementing material and a preparation method thereof.

Background

Blast furnace slag is a byproduct in the blast furnace ironmaking process and is a main component of industrial solid waste. The large amount of blast furnace slag is produced and accumulated, which not only causes the problems of environmental pollution, resource waste and the like, but also restricts the healthy development of the steel industry to a certain extent.

The development of alkali-activated slag cement is one of the effective ways to utilize excess slag resources. The alkali-activated slag gel material is a low-carbon gel material prepared by utilizing the potential activity of blast furnace slag and performing chemical reaction with raw materials such as alkali-activated agents (such as sodium hydroxide, sodium silicate, calcium carbonate and the like). Although the alkali-activated slag cementing material has the advantages of high early strength, corrosion resistance, high temperature resistance, low production energy consumption and the like. However, the alkali slag cementing material has the problems of poor toughness and large shrinkage.

Disclosure of Invention

The invention provides a modifier for regulating and controlling shrinkage of alkali-activated slag cementing material based on components, the alkali-activated slag cementing material and a preparation method thereof.

The invention provides a modifier for regulating shrinkage of alkali-activated slag cementing materials based on components, which comprises, by mass, 0.5-5 parts of mineral powder, 0.5-4 parts of steel slag powder, 0.5-2.5 parts of desulfurized gypsum and 0.1-0.5 part of expansive soil.

Preferably, the specific surface area of the mineral powder is 400-480 m ²·kg^-1;

The mineral powder comprises SiO₂29.557～32.869％、Fe₂O₃0.262～0.274％、MgO 8.542～9.662％、Al₂O₃17.873～21.557％、CaO 34.581～36.223％、K₂O0.26～0.4％、Na₂O 0.53～0.73％、MnO 0.09～0.16％、 of other 2.979-3.451% by mass.

Preferably, the specific surface area of the steel slag powder is 410-470 m ²·kg^-1;

The steel slag powder comprises SiO₂11.26～13.95％、Fe₂O₃12.11～15.52％、MgO 3.93～5.01％、Al₂O₃8.76～10.26％、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％,SO₃2.97～4.05％,% of other 5.159-5.586% by mass.

Preferably, the specific surface area of the desulfurized gypsum is 350-400 m ²·kg^-1;

The desulfurized gypsum comprises ：SiO₂11.23～15.77％、Fe₂O₃0.09～0.11％、MgO 2.52～2.58％、Al₂O₃1.42～1.77％、CaO 38.55～41.27％、P₂O₅0.04～0.11％、K₂O0.07～0.16％、Na₂O 0.5～0.72％、MnO 0.05～0.08％、TiO₂0.02～0.03％,S28.47～32.92％,SO₃8.92～12.13％, of other 0.13-0.34% by mass fraction.

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%.

The invention also provides an alkali-activated slag cementing material which comprises the following preparation raw materials in parts by mass:

the modifier comprises the modifier according to any one of claims 1 to 5.

Preferably, the specific surface area of the blast furnace slag is 450-4816 m ²·kg^-1;

The blast furnace slag comprises ：SiO₂31.22～33.58％、Fe₂O₃0.03～0.07％、MgO 7.54～8.99％、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％, of other 1.62-2.37% by mass fraction.

Preferably, the modulus of the alkali excitation solution is 1-1.4.

The invention also provides a preparation method of the alkali-activated slag cementing material, which comprises the following steps:

And mixing the blast furnace slag, the alkali-activated solution, water and the modifier, and then forming and curing to obtain the alkali-activated slag cementing material.

Preferably, the curing comprises normal temperature curing and standard curing;

The normal temperature maintenance time is 1d;

The humidity during standard curing is 95%, and the temperature is 20+/-2 ℃.

According to the modifier for regulating and controlling the shrinkage of the alkali-activated slag cementing material based on the components, the steel slag powder in the components can provide Ca ²⁺ which is absent in the hydration process of the alkali-activated slag cementing material to generate C-S- (A) -H gel, so that the porosity of the alkali-activated slag cementing material is reduced, and the drying shrinkage development of the alkali-activated slag cementing material is facilitated. The hydration products of the desulfurized gypsum, namely the dihydrate gypsum and the ettringite, have certain micro-expansion, so that shrinkage deformation of the slag cementing material excited by alkali is reduced. Meanwhile, SO ₄ ^2- dissolved out by mineral powder and desulfurized gypsum can induce a calcium-rich layer (the calcium-rich layer can obstruct the accumulation of components, thereby limiting the radial growth and axial growth of C-S- (A) -H gel) to be rapidly absorbed in water and dissolved, SO that the structure of the alkali-activated slag cementing material is more compact, and the bearing capacity and the compressive strength of the alkali-activated slag cementing material are improved. The expansive soil is low in price, wherein mineral components (montmorillonite and illite) easy to expand have certain water absorbability and expansibility, so that the dry shrinkage expansion rate of the alkali-activated slag cementing material is reduced, and the shrinkage resistance of the slag cementing material is improved.

The invention effectively utilizes solid waste materials such as desulfurized gypsum, steel slag powder, expansive soil, blast furnace slag and the like, reduces the demand for natural resources, generates great economic and social benefits, and is beneficial to sustainable development and environmental protection.

The invention utilizes the desulfurized gypsum with micro-expansion and the expansive soil to improve the shrinkage performance of the alkali-activated slag cementing material, reduce crack development and effectively improve the working performance of the alkali-activated slag cementing material.

In summary, in order to solve the problems of poor toughness and large shrinkage of the alkali-activated slag material, the invention utilizes the micro-expansibility of the cementing material desulfurized gypsum and expansive soil and the porosity of the test block reduced by the C-S- (A) -H gel of the hydration product of the steel slag, thereby solving the problem of large shrinkage of the alkali-activated slag material. Meanwhile, SO ₄ ^2- dissolved out by mineral powder and desulfurized gypsum can induce the calcium-rich layer to quickly absorb water and dissolve, SO that the alkali-activated slag cementing material structure is more compact, and the bearing capacity and the compressive strength of the alkali-activated slag cementing material are improved. Compared with the existing shrinkage modifier, the invention has the innovation point that the proposed shrinkage modifier introduces the micro-expansibility of the desulfurized gypsum into the environment of the alkaline slag material for the first time on the basis of full solid waste and is used for solving the shrinkage problem. The method meets the national sustainable development concept requirement, and has great practical significance for developing the building industry and protecting the ecological environment.

Detailed Description

The invention provides a modifier for regulating and controlling shrinkage of alkali-activated slag cementing material based on components, which comprises the following components in parts by mass:

the modifier comprises 0.5-3 parts by weight of mineral powder, wherein in a specific embodiment of the invention, the mineral powder in the modifier can be 0.5 part by weight, 1 part by weight, 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight or 3 parts by weight, the specific surface area of the mineral powder is preferably 400-480 m ²·kg^-1, and in a specific embodiment of the invention, the specific surface area of the mineral powder can be 400m²·kg^-1、410m²·kg^-1、420m²·kg^-1、430m²·kg^-1、450m²·kg^-1、460m²·kg^-1、470m²·kg^-1 or 480m ²·kg^-1;

In the invention, the mineral powder preferably comprises SiO₂29.557～32.869％、Fe₂O₃0.262～0.274％、MgO8.542～9.662％、Al₂O₃17.873～21.557％、CaO34.581～36.223％、K₂O 0.26～0.4％、Na₂O 0.53～0.73％、MnO 0.09～0.16％、 of other 2.979-3.451% by mass, and the mineral powder more preferably comprises SiO₂30～31％、Fe₂O₃0.265～0.27％、MgO9～9.5％、Al₂O₃18～19％、CaO35～35.5％、K₂O0.3～0.35％、Na₂O0.6～0.7％、MnO 0.12～0.15％、 of other 3-3.3% by mass.

Based on the mass parts of the mineral powder, the modifier provided by the invention comprises 0.5-4 parts of steel slag powder, in a specific embodiment of the invention, the mass parts of the steel slag powder in the modifier can be 0.5 part, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 3.8 parts or 4 parts, the specific surface area of the steel slag powder is preferably 410-470 m ²·kg^-1, and in a specific embodiment of the invention, the specific surface area of the steel slag powder can be 410m²·kg^-1、420m²·kg^-1、430m²·kg^-1、450m²·kg^-1、460m²·kg^-1、462m²·kg^-1 or 470m ²·kg^-1.

The steel slag powder preferably comprises SiO₂11.26～13.95％、Fe₂O₃12.11～15.52％、MgO3.93～5.01％、Al₂O₃8.76～10.26％、 CaO46.21～48.08％、 K₂O0.14～0.23％、Cl 0.397～0.554％、Na₂O 0.779～0.850％、MnO 1.75～1.87％、F0.227～0.348％,SO₃2.97～4.05％, of other 5.159-5.586% by mass, and the steel slag powder more preferably comprises SiO₂12～13％、 Fe₂O₃13～15％、 MgO4～4.5％、 Al₂O₃9～10％、 CaO46.5～48％、K₂O 0.15～0.2％、Cl 0.5～0.55％、Na₂O 0.8～0.840％、MnO 1.8～1.85％、F 0.25～0.3％,SO₃3～3.5％, of other 5.3-5.5% by mass.

Based on the mass parts of the mineral powder, the modifier provided by the invention comprises 0.5-2.5 parts of desulfurized gypsum, wherein in a specific embodiment of the invention, the mass parts of desulfurized gypsum in the modifier can be 0.5 part, 0.6 part, 1.5 part, 1.8 part or 2.5 parts, the specific surface area of the desulfurized gypsum is preferably 350-400 m ²·kg^-1, and in a specific embodiment of the invention, the specific surface area of the desulfurized gypsum can be 350m²·kg^-1、 360m²·kg^-1、 370m²·kg^-1、 380m²·kg^-1、 390m²·kg^-1 or 400m ²·kg^-1;

The desulfurized gypsum preferably comprises ：SiO₂11.23～15.77％、Fe₂O₃0.09～0.11％、MgO2.52～2.58％、Al₂O₃1.42～1.77％、CaO38.55～41.27％、P₂O₅0.04～0.11％、K₂O 0.07～0.16％、Na₂O 0.5～0.72％、MnO 0.05～0.08％、TiO₂0.02～0.03％,S28.47～32.92％,SO₃8.92～12.13％, of other 0.13-0.34% by mass fraction, and the desulfurized gypsum more preferably comprises ：SiO₂12～13％、Fe₂O₃0.1％、MgO2.54～2.55％、Al₂O₃1.5～1.7％、CaO 39～40％、P₂O₅0.05～0.08％、K₂O 0.1～0.12％、Na₂O 0.6～0.7％、MnO 0.06～0.07％、S29～30％,SO₃9～11％, of other 0.2-0.3% by mass fraction.

Based on the mass parts of the mineral powder, the modifier provided by the invention comprises 0.1-0.5 part of expansive soil, and in a specific embodiment of the invention, the mass parts of expansive soil in the modifier can be 0.1 part, 0.12 part, 0.15 part, 0.2 part, 0.25 part, 0.3 part, 0.35 part, 0.45 part, 0.48 part or 0.5 part.

In the 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 water content is preferably 16.8-18.5%.

The invention also provides an alkali-activated slag cementing material which comprises the following preparation raw materials in parts by mass:

The modifier is the modifier in the technical scheme.

In the invention, the preparation raw materials of the alkali-activated slag cementing material comprise 60-90 parts of blast furnace slag by mass, in a specific embodiment of the invention, the mass parts of blast furnace slag in the preparation raw materials of the alkali-activated slag cementing 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 450-4818 m ²·kg^-1, and in a specific embodiment of the invention, the specific surface area of the blast furnace slag can be 450m²·kg^-1、460m²·kg^-1、470m²·kg^-1、480m²·kg^-1 or 486m ²·kg^-1;

the blast furnace slag preferably comprises ：SiO₂31.22～33.58％、Fe₂O₃0.03～0.07％、MgO7.54～8.99％、Al₂O₃8.72～10.95％、CaO42.75～44.02％、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％, of other 1.62-2.37% by mass fraction, and the blast furnace slag more preferably comprises ：SiO₂32～33％、Fe₂O₃0.04～0.05％、MgO8～8.5％、Al₂O₃9～10％、CaO43～44％、P₂O₅0.03％、K₂O 0.5～0.6％、Na₂O 0.4～0.6％、MnO 0.3～0.4％、TiO₂0.7～0.8％,S1.6～2％, of other 1.9-2% by mass fraction.

Based on the mass parts of the blast furnace slag, the preparation raw materials of the alkali-activated slag cementing material comprise 16-52 parts of alkali-activated solution, in a specific embodiment of the invention, the mass parts of the alkali-activated solution in the preparation raw materials of the alkali-activated slag cementing 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 1-1.4, and in a specific embodiment of the invention, the modulus of the alkali-activated solution can be 1, 1.2 or 1.4.

In the invention, the preparation method of the alkali-activator solution preferably comprises the steps of mixing sodium silicate with NaOH and standing to obtain the alkali-activator solution.

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

Based on the mass parts of the blast furnace slag, the preparation raw materials of the alkali-activated slag cementing material comprise 21-39 parts of water, and in a specific embodiment of the invention, the mass parts of the water in the preparation raw materials of the alkali-activated slag cementing material can be 21 parts, 25 parts, 30 parts, 35 parts or 39 parts.

Based on the mass parts of the blast furnace slag, the preparation raw materials of the alkali-activated slag cementing material comprise 5-12 parts of modifier, and in a specific embodiment of the invention, the mass parts of the modifier in the preparation raw materials of the alkali-activated slag cementing material can be 5 parts, 5.5 parts, 6 parts, 10 parts or 11 parts.

The invention also provides a preparation method of the alkali-activated slag cementing material, which comprises the following steps:

and mixing the preparation raw materials of the alkali-activated slag cementing material, and then forming and curing to obtain the alkali-activated slag cementing material.

In the present invention, the molding is preferably preceded by injecting the slurry obtained after the mixing into a mold.

In the present invention, the mixing preferably includes mixing the blast furnace slag and the modifier and then mixing with the alkali-activator solution and water.

In the invention, the time of normal temperature maintenance is preferably 1d;

And after normal temperature curing, the mold is preferably opened to demold the obtained test piece before standard curing.

In the present invention, the humidity of the standard curing is preferably 95% and the temperature is preferably 20.+ -. 2 ℃.

The modifier for controlling shrinkage of alkali-activated slag cement based on components, the alkali-activated slag cement, and the method for preparing the same, which are provided by the present invention, are described in detail below with reference to examples, but they should not be construed as limiting the scope of the present invention.

In the examples:

The specific surface area of the desulfurized gypsum is 360m ²·kg^-1;

The components of the desulfurized gypsum are ：SiO₂15.77％、Fe₂O₃0.11％、MgO2.58％、Al₂O₃1.42％、CaO 38.55％、P₂O₅0.11％、K₂O 0.16％、Na₂O 0.5％、MnO0.05％、TiO₂0.02％,S28.47％,SO₃12.13％, and other 0.13 percent in mass fraction.

The specific surface area of the blast furnace slag is 480m ²·kg^-1;

The blast furnace slag comprises ：SiO₂33.58％、Fe₂O₃0.03％、MgO7.54％、Al₂O₃8.72％、CaO 44.02％、P₂O₅0.04％、K₂O 0.4％、Na₂O 0.72％、MnO0.29％、TiO₂0.92％,S1.37％, percent of other 2.37 percent of components in percentage by mass.

The specific surface area of the steel slag powder is 438m ²·kg^-1;

The steel slag powder comprises ：SiO₂13.95％、Fe₂O₃12.11％、MgO 5.01％、Al₂O₃8.76％、CaO 48.08％、K₂O 0.14％、Cl 0.397％、Na₂O 0.779％、MnO 1.87％、F 0.348％,SO32.97％,% of other 5.586% of components in percentage by mass.

The specific surface area of the mineral powder is 460m ²·kg^-1;

The mineral powder comprises ：SiO₂32.869％、Fe₂O₃0.274％、MgO9.662％、Al₂O₃17.873％、CaO 34.581％、K₂O 0.4％、Na₂O 0.73％、MnO 0.16％、 of other 3.451% of components in percentage by mass.

The expansion soil liquid limit is 46.4%, the plastic limit is 18.5%, the plasticity index is 23.4, the free expansion rate is 46.4%, the shrinkage limit is 14.5%, and the water content is 16.8%.

The preparation method of the alkali-activated slag cementing material in the embodiment comprises the following steps:

1) Adding an alkali-activated agent solution and water into the uniformly mixed powder at normal temperature and pressure, uniformly stirring to obtain alkali-activated slag gel material slurry, stirring for 1min, then injecting into a mould for vibration molding, curing at normal temperature, and demoulding after 1d to obtain alkali-activated slag gel material clean slurry test pieces (the length, width and height are respectively 160 x 40 (mm));

2) And (3) carrying out standard maintenance on the test piece at the temperature of 20+/-2 ℃ under the humidity of 95%, so as to obtain the alkali-activated slag cementing material.

Example 1

Firstly, industrial water glass with the modulus n of 3.22 (the water content of 64 wt%) is mixed with chemically pure NaOH, stirred at normal temperature, and an alkali excitation solution with the modulus of 1.2 is prepared, and is used after standing for one day.

According to the weight portion, 95 portions of blast furnace slag micropowder, 40 portions of alkali-activated solution, 30 portions of water, 5.7 portions of modifier (2.5 portions of mineral powder, 2.5 portions of steel slag powder, 0.5 portion of desulfurized gypsum and 0.2 portion of expansive soil) are weighed, and the alkali-activated slag cementing material prepared by mixing according to the proportion has the performance which is detected to be the same as the performance of alkali-activated slag cementing material prepared without adding the modifier (the rest is the same as in example 1), and the results are shown in table 1.

Example 2

Firstly, industrial water glass with the modulus n of 3.22 (the water content of 64 wt%) is mixed with chemically pure NaOH, stirred at normal temperature, and an alkali excitation solution with the modulus of 1.0 is prepared, and is used after standing for one day.

According to the weight portion, 95 portions of blast furnace slag micropowder, 40 portions of alkali-activated solution, 30 portions of water, 6.6 portions of modifier (3.5 portions of mineral powder, 2.5 portions of steel slag powder, 0.5 portion of desulfurized gypsum and 0.1 portion of expansive soil) are weighed, and the alkali-activated slag cementing material prepared by mixing according to the proportion has the performance which is detected to be the same as the performance of alkali-activated slag cementing material prepared without adding the modifier (the rest is the same as in example 2), and the results are shown in table 1.

Example 3

Firstly, industrial water glass with the modulus n of 3.22 (the water content of 64 wt%) is mixed with chemically pure NaOH, stirred at normal temperature, and an alkali excitation solution with the modulus of 1.4 is prepared, and is used after standing for one day.

According to the weight portion, weighing 95 portions of blast furnace slag micropowder, 40 portions of alkali-activated solution, 30 portions of water, 9 portions of modifier (3.5 portions of mineral powder, 3.0 portions of steel slag powder, 2.0 portions of desulfurized gypsum and 0.5 portion of expansive soil), mixing the above materials according to the proportion, and testing the performance of the alkali-activated slag cementing material prepared by mixing the above materials according to the proportion, wherein the performance of the alkali-activated slag cementing material is the same as that of the alkali-activated slag cementing material prepared without the modifier (the rest of the alkali-activated slag cementing material is the same as that of example 3), wherein the results are shown in Table 1.

Example 4

Firstly, industrial water glass with the modulus n of 3.22 (the water content of 64 wt%) is mixed with chemically pure NaOH, stirred at normal temperature, and an alkali excitation solution with the modulus of 1.2 is prepared, and is used after standing for one day.

90 Parts of blast furnace slag micropowder, 32 parts of alkali-activated solution, 30 parts of water, 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 part of expansive soil) are weighed according to the weight parts, and the alkali-activated slag cementing material prepared by mixing the materials in the proportion has the performance which is tested to be the same as that of the alkali-activated slag cementing material prepared without the modifier (the rest is the same as in example 4), and the results are shown in table 1.

Example 5

Firstly, industrial water glass with the modulus n of 3.22 (the water content of 64 wt%) is mixed with chemically pure NaOH, stirred at normal temperature, and an alkali excitation solution with the modulus of 1.2 is prepared, and is used after standing for one day.

According to the weight portions, 85 portions of blast furnace slag micropowder, 32 portions of alkali-activated solution, 30 portions of water, 8.5 portions of modifier (4.5 portions of mineral powder, 2.0 portions of steel slag powder, 1.5 portions of desulfurized gypsum and 0.5 portion of expansive soil) are weighed, and the alkali-activated slag cementing material prepared by mixing according to the proportion has the performance which is detected to be the same as that of alkali-activated slag cementing material prepared without adding the modifier (the rest is the same as that of example 5), and the results are shown in table 1.

Example 6

Firstly, industrial water glass with the modulus n of 3.22 (the water content of 64 wt%) is mixed with chemically pure NaOH, stirred at normal temperature, and an alkali excitation solution with the modulus of 1.2 is prepared, and is used after standing for one day.

80 Parts of blast furnace slag micropowder, 24 parts of alkali-activated solution, 30 parts of water, 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 part of expansive soil) are weighed according to the weight parts, and the alkali-activated slag cementing material prepared by mixing the materials in the proportion has the performance which is tested to be the same as that of the alkali-activated slag cementing material prepared without the modifier (the rest is the same as in example 6), and the results are shown in table 1.

Example 7

Firstly, industrial water glass with the modulus n of 3.22 (the water content of 64 wt%) is mixed with chemically pure NaOH, stirred at normal temperature, and an alkali excitation solution with the modulus of 1.2 is prepared, and is used after standing for one day.

75 Parts of blast furnace slag micropowder, 32 parts of alkali-activated solution, 30 parts of water, 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 part of expansive soil) are weighed according to the weight parts, and the alkali-activated slag cementing material prepared by mixing the materials in the proportion has the performance which is tested to be the same as that of the alkali-activated slag cementing material prepared without the modifier (the rest is the same as in example 7), and the results are shown in table 1.

Example 8

Firstly, industrial water glass with the modulus n of 3.22 (the water content of 64 wt%) is mixed with chemically pure NaOH, stirred at normal temperature, and an alkali excitation solution with the modulus of 1.2 is prepared, and is used after standing for one day.

80 Parts of blast furnace slag micropowder, 32 parts of alkali-activated solution, 30 parts of water, 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 part of expansive soil) are weighed according to the weight parts, and the alkali-activated slag cementing material prepared by mixing the materials in the proportion is tested for performance and the alkali-activated slag cementing material prepared without the modifier (the rest is the same as in example 8), and the results are shown in Table 1.

Example 9

Firstly, industrial water glass with the modulus n of 3.22 (the water content of 64 wt%) is mixed with chemically pure NaOH, stirred at normal temperature, and an alkali excitation solution with the modulus of 1.2 is prepared, and is used after standing for one day.

100 Parts of blast furnace slag micropowder, 40 parts of alkali-activated solution, 30 parts of water, 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 part of expansive soil) are weighed according to the weight parts, and the alkali-activated slag cementing material prepared by mixing the materials in the proportion has the performance which is tested to be the same as that of the alkali-activated slag cementing material prepared without the modifier (the rest is the same as in example 9), and the results are shown in table 1.

Comparative example 1

Firstly, industrial water glass with the modulus n of 3.22 (the water content of 64 wt%) is mixed with chemically pure NaOH, stirred at normal temperature, and an alkali excitation solution with the modulus of 1.2 is prepared, and is used after standing for one day.

100 Parts of blast furnace slag micropowder, 40 parts of alkali-activated solution, 30 parts of water, 11.9 parts of modifier (6.9 parts of steel slag powder, 4.3 parts of desulfurized gypsum and 0.4 part of expansive soil) are weighed according to the weight portions, and the alkali-activated slag cementing material prepared by mixing the materials in the proportion has the performance which is tested to be the same as that of the alkali-activated slag cementing material prepared without the modifier (the rest is the same as that of comparative example 1), and the results are shown in table 1.

Comparative example 2

Firstly, industrial water glass with the modulus n of 3.22 (the water content of 64 wt%) is mixed with chemically pure NaOH, stirred at normal temperature, and an alkali excitation solution with the modulus of 1.2 is prepared, and is used after standing for one day.

100 Parts of blast furnace slag micropowder, 40 parts of alkali-activated solution, 30 parts of water, 11.9 parts of modifier (7.5 parts of mineral powder, 3.8 parts of desulfurized gypsum and 0.6 part of expansive soil) are weighed according to the weight portions, and the alkali-activated slag cementing material prepared by mixing the materials in the proportion has the performance which is tested to be the same as that of the alkali-activated slag cementing material prepared without the modifier (the rest is the same as that of comparative example 2), and the results are shown in table 1.

Comparative example 3

Firstly, industrial water glass with the modulus n of 3.22 (the water content of 64 wt%) is mixed with chemically pure NaOH, stirred at normal temperature, and an alkali excitation solution with the modulus of 1.2 is prepared, and is used after standing for one day.

100 Parts of blast furnace slag micropowder, 40 parts of alkali-activated solution, 30 parts of water, 11.9 parts of modifier (6.3 parts of mineral powder, 5.0 parts of steel slag powder and 0.6 part of expansive soil) are weighed according to the weight portions, and the alkali-activated slag cementing material prepared by mixing the materials in the proportion has the performance which is tested to be the same as that of the alkali-activated slag cementing material prepared without the modifier (the rest is the same as that of comparative example 3), and the results are shown in table 1.

Comparative example 4

Firstly, industrial water glass with the modulus n of 3.22 (the water content of 64 wt%) is mixed with chemically pure NaOH, stirred at normal temperature, and an alkali excitation solution with the modulus of 1.2 is prepared, and is used after standing for one day.

100 Parts of blast furnace slag micropowder, 40 parts of alkali-activated solution, 30 parts of water, 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) are weighed according to the weight portions, and the alkali-activated slag cementing material prepared by mixing the materials in the proportion has the performance which is tested to be the same as that of the alkali-activated slag cementing material prepared without the modifier (the rest is the same as that of comparative example 4), and the results are shown in table 1.

The alkali-activated slag cement prepared in the above examples 1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 2, 3, and 4 were tested for performance according to the "solid waste-based cement application technical scheme" (T/CECS 689-2020).

The performance indexes of the masonry mortar prepared according to the examples are shown in table 1.

Table 1 results of performance tests for various examples

As can be seen from the data in Table 1, after the modifier is added into the alkali-activated slag cementing material, the dry shrinkage expansion rate of the alkali-activated slag cementing material is improved to a certain extent, and the working performance is enhanced, i.e. the shrinkage performance of the alkali-activated slag cementing material is obviously improved by the addition of the modifier. Meanwhile, after the modifier is added into the alkali-activated slag cementing material, the compressive and flexural strength of the alkali-activated slag cementing material is improved to a certain extent. According to the invention, the modifier is added with the desulfurized gypsum with micro-expansion, so that the working performance of the cementing material is optimized, the crack development is reduced, the fracture resistance mechanical property is enhanced, and the application field of the alkali-activated slag cementing material is effectively increased.

Meanwhile, by comparing the comparative example 1 with the example 9, it is known that the modifier without mineral powder can better improve the shrinkage performance of the material, but loses certain mechanical properties, resulting in the reduction of the overall compressive and flexural strength. By comparing comparative example 2 with example 9, it is known that the modifier without added slag powder has a decrease in the efficiency of improving the shrinkage performance and mechanical properties of the material. From comparison of comparative example 3 with example 9, it is found that the mechanical properties of the materials can be better improved by the modifier without adding desulfurized gypsum, but the efficiency of optimizing the shrinkage performance of the materials is more reduced. By comparing comparative example 4 with example 9, it is seen that the modifier of unexpanded soil has some decrease in the shrinkage performance of the material. Therefore, the modifier comprises 0.5-5 parts of mineral powder, 0.5-4 parts of steel slag powder, 0.5-2.5 parts of desulfurized gypsum and 0.1-0.5 part of expansive soil.

In conclusion, the modifier provided by the invention can be applied to alkali-activated slag cementing materials to effectively improve the shrinkage performance, toughness and bearing capacity of the cementing materials, reduce the demand on natural resources, and be beneficial to sustainable development and environmental protection.

The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.

Claims (10)

1. The modifier for regulating and controlling shrinkage of the alkali-activated slag cementing material based on the components is characterized by comprising the following components in parts by mass:

2. the modifier of claim 1, wherein the mineral powder has a specific surface area of 400-480 m ²·kg^-1;

The mineral powder comprises SiO₂29.557～32.869％、Fe₂O₃0.262～0.274％、MgO 8.542～9.662％、Al₂O₃17.873～21.557％、CaO 34.581～36.223％、K₂O0.26～0.4％、Na₂O 0.53～0.73％、MnO 0.09～0.16％、 of other 2.979-3.451% by mass.

3. The modifier of claim 1, wherein the specific surface area of the steel slag powder is 410-470 mm ²·kg^-1;

The steel slag powder comprises SiO₂11.26～13.95％、Fe₂O₃12.11～15.52％、MgO 3.93～5.01％、Al₂O₃8.76～10.26％、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％,SO₃2.97～4.05％,% of other 5.159-5.586% by mass.

4. The modifier of claim 1, wherein the specific surface area of the desulfurized gypsum is 350-400 m ²·kg^-1;

The desulfurized gypsum comprises ：SiO₂11.23～15.77％、Fe₂O₃0.09～0.11％、MgO 2.52～2.58％、Al₂O₃1.42～1.77％、CaO 38.55～41.27％、P₂O₅0.04～0.11％、K₂O 0.07～0.16％、Na₂O 0.5～0.72％、MnO 0.05～0.08％、TiO₂0.02～0.03％,S28.47～32.92％,SO₃8.92～12.13％, of other 0.13-0.34% by mass fraction.

5. The modifier of claim 1, wherein the swelling 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 swelling rate of 44.2-46.4%, a shrinkage limit of 13.1-14.5%, and a water content of 16.8-18.5%.

6. The alkali-activated slag cementing material is characterized by comprising the following preparation raw materials in parts by mass:

the modifier comprises the modifier according to any one of claims 1 to 5.

7. The alkali-activated slag cement material according to claim 6, wherein the specific surface area of the blast furnace slag is 450-4818 m ²·kg^-1;

The blast furnace slag comprises ：SiO₂31.22～33.58％、Fe₂O₃0.03～0.07％、MgO 7.54～8.99％、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％, of other 1.62-2.37% by mass fraction.

8. The alkali-activated slag cement material according to claim 6, wherein the modulus of the alkali-activated solution is 1 to 1.4.

9. The method for preparing the alkali-activated slag cementing material according to any one of claims 6 to 8, which is characterized by comprising the following steps:

And mixing the blast furnace slag, the alkali-activated solution, water and the modifier, and then forming and curing to obtain the alkali-activated slag cementing material.

10. The method of claim 9, wherein the curing comprises normal temperature curing and standard curing;

The normal temperature maintenance time is 1d;

The humidity during standard curing is 95%, and the temperature is 20+/-2 ℃.