Alkali activator, alkali-activated cementitious material, preparation method and application thereof

Abstract

The present invention discloses an alkali activator, an alkali-activated cementitious material, and their preparation methods and applications. The alkali activator includes persulfate and an alkaline agent. The alkali-activated cementitious material of the present invention is prepared from the alkali activator as a raw material. The alkali activator of the present invention, under the combined action of persulfate and an alkaline agent, can rapidly activate aluminosilicate substances in industrial solid wastes under the condition of low alkali concentration, having the advantages of fast activation rate and good activation effect. At the same time, under the action of the alkali activator, industrial solid wastes rich in aluminosilicate substances can be made into alkali-activated cementitious materials with high compressive strength. In particular, in the alkali-activated cementitious material of the present invention, no other additives need to be added, and the cost is lower. It can be used to replace cement and can be widely used in the construction industry. It can not only effectively reduce carbon emissions, but also realize the resource utilization of industrial by-products, having higher use value and better application prospects.

Description

Technical Field

[0001] The present invention belongs to the field of building materials, and relates to an alkali activator, an alkali-activated cementitious material, and a preparation method and application thereof. Background Art

[0002] The construction industry has a large demand for ordinary Portland cement. However, with the extensive use of ordinary Portland cement, it has brought huge consumption of energy and resources, as well as serious environmental pollution problems. For example, the carbon dioxide emissions and energy consumption in the production process of ordinary Portland cement account for 5%-8% of the global carbon dioxide emissions and 12%-15% of the global energy consumption. Based on this, alkali-activated cementitious materials have become an environmentally friendly alternative to ordinary Portland cement, which can not only reduce carbon emissions but also realize the resource utilization of industrial by-products.

[0003] Alkali-activated cementitious materials are formed by alkali activation reaction using industrial by-products rich in aluminosilicate substances. The alkali activators used mainly include water glass (sodium silicate) and sodium hydroxide. The alkali activation process involved includes the following steps: a hydration reaction occurs in an alkaline environment, the Si-O bond and Al-O bond in the aluminosilicate-based precursor are broken, releasing silica tetrahedra and aluminate tetrahedra. Further, under the action of sodium silicate, the dissolved silicon and aluminum monomers are recombined into aluminosilicate oligomers, and finally the oligomers are further condensed into gel-phase polymers. During the alkali activation process, in order to promote the dissolution and repolymerization of aluminosilicates, it is usually necessary to add alkali activators with a high alkali concentration. However, high-concentration alkali activators have problems such as corrosiveness, high viscosity, and high cost, and when the alkali concentration is too high, it will reduce the mechanical properties of the material or cause problems such as cracking; at the same time, if the alkali concentration of the alkali activator is reduced, when the concentration of the alkali activator is low, it is easy to cause the alkali activation process to be blocked, thereby making the strength development and reaction rate of the alkali-activated material slow. Therefore, obtaining an alkali activator with a low alkali concentration, a fast activation rate, and a good activation effect is of great significance for preparing low-cost and high-strength alkali-activated cementitious materials and promoting the wide use of alkali-activated cementitious materials. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art, and provide an alkali activator with a low alkali concentration, a fast activation rate, and a good activation effect. The present invention also provides an alkali-activated cementitious material with low cost and high strength, and a preparation method and application thereof.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions:

[0006] An alkali activator, wherein the alkali activator comprises persulfate and an alkaline agent; the mass ratio of the persulfate to the alkaline agent is 0.1-3.2:0.1-3.

[0007] For the above alkali activator, further improved, the mass ratio of the persulfate to the alkaline agent is 0.4 - 2.4:0.4 - 3.

[0008] For the above alkali activator, further improved, the alkali activator further includes a solvent.

[0009] For the above alkali activator, further improved, the solvent is water.

[0010] For the above alkali activator, further improved, the mass ratio of the persulfate to water is 0.1 - 3.2:18 - 50.

[0011] For the above alkali activator, further improved, the persulfate is at least one of potassium hydrogen persulfate, sodium hydrogen persulfate, sodium persulfate, and potassium persulfate.

[0012] For the above alkali activator, further improved, the alkaline agent is at least one of sodium hydroxide, sodium silicate, potassium hydroxide, calcium hydroxide, calcium oxide, and calcium carbonate.

[0013] As a general technical concept, the present invention also provides an alkali-activated cementitious material, and the raw materials of the alkali-activated cementitious material include the above alkali activator.

[0014] For the above alkali-activated cementitious material, further improved, the raw materials of the alkali-activated cementitious material further include industrial solid waste containing aluminosilicate substances.

[0015] For the above alkali-activated cementitious material, further improved, the mass ratio of the industrial solid waste to the persulfate is 1:0.01 - 0.08.

[0016] For the above alkali-activated cementitious material, further improved, the industrial solid waste includes slag and fly ash; the mass ratio of the slag to the fly ash is 4:1.

[0017] As a general technical concept, the present invention also provides a preparation method for the above alkali-activated cementitious material, including the following steps:

[0018] S1. Mix the industrial solid waste, persulfate, and water, and stir to obtain a mixed turbid liquid;

[0019] S2. Mix the mixed turbid liquid obtained in step S1 with the alkaline agent to obtain a mixed slurry;

[0020] S3. Mold and cure the mixed slurry obtained in step S2 to obtain the alkali-activated cementitious material.

[0021] As a general technical concept, the present invention also provides a method for preparing the above alkali-activated cementitious material, comprising the following steps:

[0022] (1) Mix fly ash, persulfate and water, and stir to obtain a mixed turbid liquid;

[0023] (2) Mix the mixed turbid liquid obtained in step (1), slag and an alkaline agent to obtain a mixed slurry;

[0024] (3) Mold and cure the mixed slurry obtained in step (2) to obtain the alkali-activated cementitious material.

[0025] As a general technical concept, the present invention also provides an application of the above alkali-activated cementitious material as cement in the construction industry.

[0026] As a general technical concept, the present invention also provides an application of the alkali-activated cementitious material prepared by the above preparation method as cement in the construction industry.

[0027] Compared with the prior art, the advantages of the present invention are as follows:

[0028] (1)In view of the deficiencies of existing high-alkali-concentration alkali activators, such as corrosion, high viscosity, high cost, and the resulting low strength and easy cracking of alkali-activated cementitious materials, and in view of the deficiencies of existing low-alkali-concentration alkali activators, such as low activation efficiency and poor activation effect, and the resulting difficulties in making industrial by-products rich in aluminosilicate substances into high-strength alkali-activated cementitious materials, or difficulties in preparing high-strength alkali-activated cementitious materials at low cost, the present invention creatively proposes an alkali activator comprising persulfate and an alkaline agent. In the present invention, when persulfate and an alkaline agent are used as the alkali activator to activate industrial solid waste rich in aluminosilicate substances, in the alkaline environment constructed by the alkaline agent, part of the persulfate will be converted into free radicals. Thus, under the combined action of the free radicals and the alkaline agent, the ability to attack Si-O and Al-O bonds can be enhanced, so that the breaking of Si-O and Al-O bonds in the raw materials can be promoted even under the condition of low alkali concentration, and the depolymerization and dissolution of aluminosilicate substances can be significantly improved and enhanced. At the same time, under the combined action of persulfate and the alkaline agent, new Si-O-Si and Si-O-Al bonds can be catalyzed and rapidly formed, generating a large amount of hydration products such as C-(A)-S-H gel and ettringite, forming high-polymerization-degree hydration products and filling the pores between unreacted particles, making the internal structure more dense. Therefore, a dense polymer can be formed without other additives. In addition, the synergistic effect of persulfate and hydroxide ions can also significantly improve the compressive strength of the material. The alkali activator of the present invention can rapidly activate the aluminosilicate substances in industrial solid waste under the condition of low alkali concentration under the combined action of persulfate and the alkaline agent, and has the advantages of fast activation rate and good activation effect. At the same time, under the action of the alkali activator of the present invention, industrial solid waste rich in aluminosilicate substances can be made into an alkali-activated cementitious material with high compressive strength.

[0029] (2)In the alkali activator of the present invention, by optimizing the mass ratio of persulfate to the alkaline agent to be 0.4 - 3.2∶0.4 - 3, it is beneficial to improve the compressive strength of the alkali-activated cementitious material. Specifically, under the condition of the same mass of persulfate, increasing the mass of the alkaline agent can provide surplus hydroxide ions to promote the activation of more aluminosilicate substances and improve the compressive strength of the alkali-activated cementitious material. However, when the mass ratio of persulfate to the alkaline agent is too low (i.e., the dosage of the alkaline agent is too high), the early compressive strength of the material will be reduced; under the condition of the same mass of the alkaline agent, increasing the mass of persulfate can provide more persulfate to promote the depolymerization and repolymerization of aluminosilicate substances during activation and synergistically act with hydroxide ions to improve the compressive strength of the material. However, when the mass ratio of persulfate to the alkaline agent is too high (i.e., the dosage of persulfate is too high), the pH of the system will decrease during the alkali activation process, resulting in slow material reaction or inability to harden.

[0030] (3) In the alkali activator of the present invention, a solvent is further included. The solvent is water, and the mass ratio of persulfate to water is optimized to be 0.1 - 3.2∶18 - 50. Adding an appropriate amount of water to the alkali activator can adjust the concentration of the persulfate solution, thereby ensuring that more persulfate reacts synergistically with the alkaline reagent, further activating the aluminosilicate substances in more industrial solid wastes, and ultimately effectively improving the compressive strength of the material.

[0031] (4) The present invention also provides an alkali-activated cementitious material. Using industrial solid wastes rich in aluminosilicate substances as the precursor and persulfate and alkaline reagents as the alkali activator, it can produce an alkali-activated cementitious material with high compressive strength from industrial solid wastes rich in aluminosilicate substances under the action of an alkali activator with a low alkali concentration. In particular, in this alkali-activated cementitious material, no other additives need to be added, and the cost is lower. Therefore, it can be widely used to replace cement and has higher use value and better application prospects.

[0032] (5) In the alkali-activated cementitious material of the present invention, by optimizing the mass ratio of industrial solid waste to persulfate to be 1∶0.01 - 0.08, it can ensure that the alkali activator can effectively activate the aluminosilicate substances in the industrial solid waste and ensure that the industrial solid waste is made into an alkali-activated cementitious material with high compressive strength. Description of the Drawings

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0034] Figure 1 It is a graph of the compressive strength results of the alkali-activated cementitious materials (S0.5P0.4, S0.5P0.8, S0.5P1.6) prepared in Embodiments 1 - 3 of the present invention and the alkali-activated cementitious material (S0.5P0) prepared in Comparative Example 1.

[0035] Figure 2 It is a comparative graph of the compressive strength results of the alkali-activated cementitious materials (S1P0.4, S1P0.8, S1P1.6, S1P3.2) prepared in Embodiments 4 - 7 of the present invention and the alkali-activated cementitious material (S1P0) prepared in Comparative Example 2.

[0036] Figure 3 It is a graph of the compressive strength results of the alkali-activated cementitious materials (S1.5P0.4, S1.5P0.8, S1.5P1.6, S1.5P3.2) prepared in Embodiments 8 - 11 of the present invention and the alkali-activated cementitious material (S1.5P0) prepared in Comparative Example 3.

[0037] Figure 4 Compressive strength result graphs of the alkali-activated binders (S1.5P0, S1.5P0.4, S1.5P0.8, S1.5P1.6, S1.5P3.2) prepared in Examples 8-11 and Comparative Examples 3-7 of the present invention.

[0038] Figure 5 Compressive strength result graphs of the alkali-activated binders (S2P0.4, S2P0.8, S2P1.6, S2P3.2) prepared in Examples 12-15 of the present invention and the alkali-activated binder (S2P0) prepared in Comparative Example 8.

[0039] Figure 6 Compressive strength result graphs of the alkali-activated binders (S4P0.4, S4P0.8, S4P1.6, S4P3.2) prepared in Examples 16-19 of the present invention and the alkali-activated binder (S4P0) prepared in Comparative Example 9.

[0040] Figure 7 Graph showing the relationship between time and dissolution concentration during the solid waste dissolution process in the persulfate / alkali-activation reaction system (S1.5P1, S1.5P2, S1.5P4, S1.5P8) based on persulfate and alkaline agents and the alkali-activation reaction system (S1.5P0) based on alkaline agents prepared in Examples 20-23 of the present invention and Comparative Example 10. Detailed implementation manners

[0041] Aiming at the deficiencies of existing high-alkali-concentration alkali activators, such as corrosion, high viscosity, high cost, etc., and the resulting defects of low strength and easy cracking of alkali-activated binders, and at the same time aiming at the deficiencies of existing low-alkali-concentration alkali activators, such as low activation efficiency and poor activation effect, and the resulting defects of difficulty in making industrial by-products rich in aluminosilicate substances into high-strength alkali-activated binders, or difficulty in preparing high-strength alkali-activated binders at low cost, etc., in this embodiment, a creative alkali activator is proposed, which includes persulfate and alkaline agents. It can be seen that the alkali activator of this embodiment takes persulfate and alkaline agents as active ingredients, where persulfate refers to salts containing persulfate or bisulfate ions, and alkaline agents refer to alkaline substances containing hydroxide ions.

[0042] In the alkali activator of this embodiment, the mass ratio of persulfate to alkaline agent is 0.1-3.2:0.1-3. As a further preferred scheme, the mass ratio of persulfate to alkaline agent is 0.4-2.4:0.4-3.

[0043] In the alkali activator of this embodiment, the alkali activator further includes a solvent.

[0044] In the alkali activator of this embodiment, the solvent is water.

[0045] In the alkali activator of this embodiment, the mass ratio of persulfate to water is 0.1 - 3.2:18 - 50.

[0046] In the alkali activator of this embodiment, the persulfate is at least one of potassium bisulfate, sodium bisulfate, sodium persulfate, and potassium persulfate.

[0047] In the alkali activator of this embodiment, the alkaline agent is at least one of sodium hydroxide, sodium silicate, potassium hydroxide, calcium hydroxide, calcium oxide, and calcium carbonate.

[0048] The second object of the present invention is to provide an alkali-activated cementitious material, and the raw materials of the alkali-activated cementitious material include the alkali activator of the present invention described above.

[0049] In the alkali-activated cementitious material of this embodiment, the raw materials used further include industrial solid waste containing aluminosilicate substances.

[0050] In the alkali-activated cementitious material of this embodiment, the mass ratio of industrial solid waste to the persulfate is 1:0.01 - 0.08.

[0051] In the alkali-activated cementitious material of this embodiment, the industrial solid waste includes slag and fly ash; the mass ratio of slag to fly ash is 4:1.

[0052] The third object of the present invention is to provide a preparation method of an alkali-activated cementitious material, including the following steps:

[0053] S1. Mix industrial solid waste, persulfate, and water, and stir to obtain a mixed turbid liquid;

[0054] S2. Mix the mixed turbid liquid obtained in step S1 with an alkaline agent to obtain a mixed slurry;

[0055] S3. Mold and cure the mixed slurry obtained in step S2 to obtain an alkali-activated cementitious material.

[0056] The fourth object of the present invention is to provide a preparation method of an alkali-activated cementitious material, including the following steps:

[0057] (1) Mix fly ash, persulfate, and water, and stir to obtain a mixed turbid liquid;

[0058] (2) Mix the mixed turbid liquid obtained in step (1), slag, and an alkaline agent to obtain a mixed slurry;

[0059] (3) Mold and cure the mixed slurry obtained in step (2) to obtain an alkali-activated cementitious material.

[0060] The fifth object of the present invention is to provide an application of an alkali-activated cementitious material as cement in the construction industry.

[0061] The present invention will be further described below in conjunction with the accompanying drawings of the specification and specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0062] In the following embodiments of the present invention, unless otherwise specified, the materials and instruments used are commercially available, the equipment used is conventional equipment, and the obtained data are the averages of more than three repeated experiments.

[0063] Example 1

[0064] An alkali activator includes persulfate and an alkaline agent.

[0065] In this embodiment, the mass ratio of persulfate to the alkaline agent is 1:1.

[0066] In this embodiment, the alkali activator further includes a solvent, and the solvent is water. The mass ratio of persulfate to water is 0.2:9.

[0067] In this embodiment, the persulfate is potassium hydrogen persulfate, and the alkaline agent is sodium hydroxide.

[0068] An alkali-activated cementitious material includes the following raw material components: the alkali activator in the above-mentioned embodiment of the present invention and industrial solid waste containing aluminosilicate substances, wherein the mass ratio of the industrial solid waste to persulfate is 1:0.01.

[0069] In this embodiment, the industrial solid waste containing aluminosilicate substances is used as the precursor, and potassium hydrogen persulfate and sodium hydroxide are used as the effective components of the alkali activator.

[0070] In this embodiment, the industrial solid waste used is slag and fly ash, and the mass ratio of the two is 4:1.

[0071] A preparation method of the alkali-activated cementitious material in the above-mentioned embodiment of the present invention includes the following steps:

[0072] (1) By mass percentage, 8 g of fly ash solid, 18 g of water and 0.4 g of potassium hydrogen persulfate are mixed and stirred for 10 min to obtain a mixed turbid liquid.

[0073] (2) In the mixed turbid liquid obtained in step (1), 32 g of slag and 0.4 g of sodium hydroxide are added according to the mass percentage for uniform mixing to obtain a solid waste-alkali activator mixed slurry.

[0074] (3) The mixed slurry obtained in step (2) is transferred to a 20×20×20 mm six-connected steel mold for molding. After scraping the excess slurry on the surface of the mold, it is covered with a plastic wrap.

[0075] (4) Demold the sample after casting and forming in step (3) after curing at room temperature for 24 h, and then cure it at ambient temperature and humidity until 7 days and 28 days to obtain an alkali-activated cementitious material, named S0.5P0.4.

[0076] Application of the alkali-activated cementitious material in the above-mentioned embodiment as cement in the construction industry.

[0077] Comparative Example 1

[0078] A preparation method of an alkali-activated cementitious material is basically the same as that in Example 1, except that: potassium bisulfate is not added in Comparative Example 1.

[0079] The alkali-activated cementitious material prepared in Comparative Example 1 is named S0.5P0.

[0080] Example 2

[0081] An alkali activator is basically the same as that in Example 1, except that: the mass ratio of persulfate to alkaline agent in Example 2 is 2:1; the mass ratio of persulfate to water is 0.4:9.

[0082] An alkali-activated cementitious material is basically the same as that in Example 1, except that: the mass ratio of industrial solid waste to persulfate in Example 2 is 1:0.02.

[0083] A preparation method of the alkali-activated cementitious material in the above-mentioned embodiment is basically the same as that in Example 1, except that: the mass of potassium bisulfate in Example 2 is 0.8 g.

[0084] The alkali-activated cementitious material prepared in Example 2 is named S0.5P0.8.

[0085] Example 3

[0086] An alkali activator is basically the same as that in Example 1, except that: the mass ratio of persulfate to alkaline agent in Example 3 is 4:1; the mass ratio of persulfate to water is 0.8:9.

[0087] An alkali-activated cementitious material is basically the same as that in Example 1, except that: the mass ratio of industrial solid waste to persulfate in Example 3 is 1:0.04.

[0088] A preparation method in the above-mentioned embodiment is basically the same as that in Example 1, except that: the mass of potassium bisulfate in Example 3 is 1.6 g.

[0089] The alkali-activated cementitious material prepared in Example 3 is named S0.5P1.6.

[0090] Figure 1Compressive strength results graphs of the alkali-activated cementitious materials (S0.5P0.4, S0.5P0.8, S0.5P1.6) prepared in Examples 1-3 of the present invention and the alkali-activated cementitious material (S0.5P0) prepared in Comparative Example 1. From Figure 1 it can be seen that:

[0091] The compressive strength of the alkali-activated cementitious material (S0.5P0.4) prepared in Example 1 of the present invention is 13.85 MPa after 7 days of curing and 15.62 MPa after 28 days of curing.

[0092] The compressive strength of the alkali-activated cementitious material (S0.5P0.8) prepared in Example 2 of the present invention is 20.95 MPa after 7 days of curing and 19.53 MPa after 28 days of curing.

[0093] The compressive strength of the alkali-activated cementitious material (S0.5P1.6) prepared in Example 3 of the present invention is 25.60 MPa after 7 days of curing and 19.58 MPa after 28 days of curing.

[0094] The compressive strength of the alkali-activated cementitious material (S0.5P0) prepared in Comparative Example 1 is 10.04 MPa after 7 days of curing and 15.83 MPa after 28 days of curing.

[0095] The results show that: for the alkali-activated cementitious material (S0.5P1.6) prepared in Example 3 of the present invention, the compressive strength is the best after 7 days and 28 days of curing, and the compressive strengths after 7 days and 28 days of curing are 25.60 MPa and 19.58 MPa respectively. However, for the alkali-activated cementitious material (S0.5P0), the compressive strengths after 7 days and 28 days of curing are only 10.04 MPa and 15.83 MPa respectively. By comparison, it can be known that: the alkali activator of the present invention can significantly improve the compressive strength of the cementitious material, and the compressive strength of the alkali-activated cementitious material increases with the increase of the addition amount of potassium bisulfate.

[0096] Example 4

[0097] An alkali activator, comprising persulfate and an alkaline agent.

[0098] In this example, the mass ratio of persulfate to the alkaline agent is 1:1.8.

[0099] In this example, the alkali activator further comprises a solvent, the solvent is water, and the mass ratio of persulfate to water is 0.2:9.

[0100] In this example, the persulfate is potassium bisulfate and the alkaline agent is sodium hydroxide.

[0101] An alkali-activated cementitious material, comprising the following raw material components: the alkali activator and the industrial solid waste containing aluminosilicate substances in the above-mentioned present embodiment, wherein the mass ratio of the industrial solid waste to persulfate is 1:0.01.

[0102] In the present embodiment, the industrial solid waste containing aluminosilicate substances is used as the precursor, and potassium monopersulfate and sodium hydroxide are used as the effective components of the alkali activator.

[0103] In the present embodiment, the industrial solid wastes used are slag and fly ash, and the mass ratio of the two is 4:1.

[0104] A preparation method of the alkali-activated cementitious material in the above-mentioned present embodiment, comprising the following steps:

[0105] (1) By mass percentage, 8 g of fly ash solid, 18 g of water and 0.4 g of potassium monopersulfate are mixed and stirred for 10 min to obtain a mixed turbid liquid.

[0106] (2) In the mixed turbid liquid obtained in step (1), 32 g of slag and 0.72 g of sodium hydroxide are added according to the mass percentage for uniform mixing to obtain a solid waste-alkali activator mixed slurry.

[0107] (3) The mixed slurry obtained in step (2) is transferred to a 20×20×20 mm six-compartment steel mold for molding. After scraping the excess slurry on the surface of the mold, it is covered with a plastic wrap.

[0108] (4) The sample formed by pouring in step (3) is cured at room temperature for 24 h and then demolded, and then cured at the ambient temperature and humidity until 7 days and 28 days to obtain the alkali-activated cementitious material, named S1P0.4.

[0109] Comparative Example 2

[0110] A preparation method of an alkali-activated cementitious material is basically the same as that in Example 4, except that: potassium monopersulfate is not added in Comparative Example 2.

[0111] The alkali-activated cementitious material prepared in Comparative Example 2 is named S1P0.

[0112] Example 5

[0113] An alkali activator is basically the same as that in Example 4, except that: in Example 5, the mass ratio of persulfate to alkaline agent is 10:9; the mass ratio of persulfate to water is 0.4:9.

[0114] An alkali-activated cementitious material is basically the same as that in Example 4, except that: in Example 5, the mass ratio of industrial solid waste to persulfate is 1:0.02.

[0115] A preparation method of an alkali-activated cementitious material is basically the same as that in Example 4, except that: in Example 5, the mass of potassium persulfate is 0.8 g.

[0116] The alkali-activated cementitious material prepared in Example 5 is named S1P0.8.

[0117] Example 6

[0118] An alkali activator is basically the same as that in Example 4, except that: in Example 6, the mass ratio of persulfate to alkaline agent is 20∶9; the mass ratio of persulfate to water is 0.8∶9.

[0119] An alkali-activated cementitious material is basically the same as that in Example 4, except that: in Example 6, the mass ratio of industrial solid waste to persulfate is 1∶0.04.

[0120] A preparation method of an alkali-activated cementitious material is basically the same as that in Example 4, except that: in Example 6, the mass of potassium persulfate is 1.6 g.

[0121] The alkali-activated cementitious material prepared in Example 6 is named S1P1.6.

[0122] Example 7

[0123] An alkali activator is basically the same as that in Example 4, except that: in Example 7, the mass ratio of persulfate to alkaline agent is 40∶9; the mass ratio of persulfate to water is 1.6∶9.

[0124] An alkali-activated cementitious material is basically the same as that in Example 4, except that: in Example 7, the mass ratio of industrial solid waste to persulfate is 1∶0.08.

[0125] A preparation method of an alkali-activated cementitious material is basically the same as that in Example 4, except that: in Example 7, the mass of potassium persulfate is 3.2 g.

[0126] The alkali-activated cementitious material prepared in Example 7 is named S1P3.2.

[0127] Figure 2 It is a comparative chart of the compressive strength results of the alkali-activated cementitious materials (S1P0.4, S1P0.8, S1P1.6, S1P3.2) prepared in Examples 4 - 7 of the present invention and the alkali-activated cementitious material (S1P0) prepared in Comparative Example 2. From Figure 2 It can be seen that:

[0128] The alkali-activated cementitious material (S1P0.4) prepared in Example 4 of the present invention has a compressive strength of 22.98 MPa after 7 days of curing and a compressive strength of 26.12 MPa after 28 days of curing.

[0129] In Example 5 of the present invention, the alkali-activated cementitious material (S1P0.8) prepared has a compressive strength of 22.58 MPa after 7 days of curing and a compressive strength of 29.53 MPa after 28 days of curing.

[0130] In Example 6 of the present invention, the alkali-activated cementitious material (S1P1.6) prepared has a compressive strength of 26.17 MPa after 7 days of curing and a compressive strength of 37.9 MPa after 28 days of curing.

[0131] In Example 7 of the present invention, the alkali-activated cementitious material (S1P3.2) prepared has a compressive strength of 25.73 MPa after 7 days of curing and a compressive strength of 32.78 MPa after 28 days of curing.

[0132] For the alkali-activated cementitious material (S1P0) prepared in Comparative Example 2, the compressive strength is 13.58 MPa after 7 days of curing and 14.3 MPa after 28 days of curing.

[0133] The results show that: for the alkali-activated cementitious material (S1P1.6) prepared in Example 6 of the present invention, the compressive strength at 7 days and 28 days is the best, with compressive strengths of 26.17 MPa and 37.9 MPa respectively after 7 days and 28 days of curing. However, the compressive strengths of the alkali-activated cementitious material (S1P0) are only 13.58 MPa and 14.3 MPa respectively after 7 days and 28 days of curing. It can be seen by comparison that: the alkali activator of the present invention can significantly improve the compressive strength of the cementitious material.

[0134] Example 8

[0135] An alkali activator includes persulfate and an alkaline agent.

[0136] In this example, the mass ratio of persulfate to the alkaline agent is 0.1∶0.27.

[0137] In this example, the alkali activator further includes a solvent, and the solvent is water, where the mass ratio of persulfate to water is 0.2∶9.

[0138] In this example, the persulfate is potassium hydrogen persulfate and the alkaline agent is sodium hydroxide.

[0139] An alkali-activated cementitious material includes the following raw material components: the alkali activator in the present example above and an industrial solid waste containing aluminosilicate substances, where the mass ratio of the industrial solid waste to persulfate is 1∶0.01.

[0140] In this example, the industrial solid waste containing aluminosilicate substances is used as the precursor, and potassium hydrogen persulfate and sodium hydroxide are used as the effective components of the alkali activator.

[0141] In this embodiment, the industrial solid waste used is slag and fly ash, and the mass ratio of the two is 4:1.

[0142] A preparation method of the alkali-activated cementitious material of the above-mentioned embodiment includes the following steps:

[0143] (1) By mass percentage, 8 g of fly ash solid, 18 g of water and 0.4 g of potassium persulfate are mixed and stirred for 10 min to obtain a mixed turbid liquid;

[0144] (2) In the mixed turbid liquid obtained in step (1), 32 g of slag and 1.08 g of sodium hydroxide are added according to mass percentage for uniform mixing to obtain a solid waste-alkali activator mixed slurry;

[0145] (3) Transfer the mixed slurry obtained in step (2) to a 20×20×20 mm six-compartment steel mold for molding. After scraping the excess slurry on the surface of the mold, cover it with a plastic wrap;

[0146] (4) The sample molded in step (3) is cured at room temperature for 24 h and then demolded, and then cured at ambient temperature and humidity for 7 days and 28 days to obtain the alkali-activated cementitious material, named S1.5P0.4.

[0147] Example 9

[0148] An alkali activator is basically the same as that in Example 8, except that: in Example 9, the mass ratio of persulfate to alkaline agent is 0.2:0.27; the mass ratio of persulfate to water is 0.4:9.

[0149] An alkali-activated cementitious material is basically the same as that in Example 8, except that: in Example 9, the mass ratio of industrial solid waste to persulfate is 1:0.02.

[0150] A preparation method of an alkali-activated cementitious material is basically the same as that in Example 8, except that: in Example 9, the mass of potassium persulfate is 0.8 g.

[0151] The alkali-activated cementitious material prepared in Example 9 is named S1.5P0.8.

[0152] Example 10

[0153] An alkali activator is basically the same as that in Example 8, except that: in Example 10, the mass ratio of persulfate to alkaline agent is 0.4:0.27; the mass ratio of persulfate to water is 0.8:9.

[0154] An alkali-activated cementitious material is basically the same as that in Example 8, except that: in Example 10, the mass ratio of industrial solid waste to persulfate is 1:0.04.

[0155] A preparation method of an alkali-activated cementitious material is basically the same as that of Example 8, except that: in Example 10, the mass of potassium monopersulfate is 1.6 g.

[0156] The alkali-activated cementitious material prepared in Example 10 is named S1.5P1.6.

[0157] Example 11

[0158] An alkali activator is basically the same as that of Example 8, except that: in Example 11, the mass ratio of persulfate to alkaline agent is 0.8∶0.27; the mass ratio of persulfate to water is 1.6∶9.

[0159] An alkali-activated cementitious material is basically the same as that of Example 8, except that: in Example 11, the mass ratio of industrial solid waste to persulfate is 1∶0.08.

[0160] A preparation method of an alkali-activated cementitious material is basically the same as that of Example 8, except that: in Example 11, the mass of potassium monopersulfate is 3.2 g.

[0161] The alkali-activated cementitious material prepared in Example 11 is named S1.5P3.2.

[0162] Comparative Example 3

[0163] A preparation method of an alkali-activated cementitious material is basically the same as that of Example 8, except that: in Comparative Example 3, potassium monopersulfate is not added.

[0164] The alkali-activated cementitious material prepared in Comparative Example 3 is named S1.5P0.

[0165] Comparative Example 4

[0166] An alkali activator is basically the same as that of Example 8, except that: in Comparative Example 4, potassium sulfate is used instead of persulfate; the mass ratio of potassium sulfate to alkaline agent is 0.4535∶1.08; the mass ratio of potassium sulfate to water is 0.4535∶18.

[0167] An alkali-activated cementitious material is basically the same as that of Example 8, except that: in Comparative Example 4, the mass ratio of industrial solid waste to potassium sulfate is 40∶0.4535.

[0168] An alkali-activated cementitious material is basically the same as that of Example 8, except that: in Comparative Example 4, the mass of potassium sulfate is 0.4535 g.

[0169] The alkali-activated cementitious material prepared in Comparative Example 4 is named S1.5P0.4.

[0170] Comparative Example 5

[0171] An alkali activator, which is basically the same as that in Example 8, except that in Comparative Example 5, potassium sulfate is used instead of persulfate; the mass ratio of potassium sulfate to the alkaline agent is 0.9071∶1.08; the mass ratio of potassium sulfate to water is 0.9071∶18.

[0172] An alkali-activated cementitious material, which is basically the same as that in Example 8, except that in Comparative Example 5, the mass ratio of industrial solid waste to potassium sulfate is 40∶0.9071.

[0173] An alkali-activated cementitious material, which is basically the same as that in Example 8, except that in Comparative Example 5, the mass of potassium sulfate is 0.9071 g.

[0174] The alkali-activated cementitious material prepared in Comparative Example 5 is named S1.5P0.8.

[0175] Comparative Example 6

[0176] An alkali activator, which is basically the same as that in Example 8, except that in Comparative Example 6, potassium sulfate is used instead of persulfate; the mass ratio of potassium sulfate to the alkaline agent is 1.8141∶1.08; the mass ratio of potassium sulfate to water is 1.8141∶18.

[0177] An alkali-activated cementitious material, which is basically the same as that in Example 8, except that in Comparative Example 6, the mass ratio of industrial solid waste to potassium sulfate is 40∶1.8141.

[0178] An alkali-activated cementitious material, which is basically the same as that in Example 8, except that in Comparative Example 6, the mass of potassium sulfate is 1.8141 g.

[0179] The alkali-activated cementitious material prepared in Comparative Example 6 is named S1.5P1.6.

[0180] Comparative Example 7

[0181] An alkali activator, which is basically the same as that in Example 8, except that in Comparative Example 7, potassium sulfate is used instead of persulfate; the mass ratio of potassium sulfate to the alkaline agent is 3.6283∶1.08; the mass ratio of potassium sulfate to water is 3.6283∶18.

[0182] An alkali-activated cementitious material, which is basically the same as that in Example 8, except that in Comparative Example 7, the mass ratio of industrial solid waste to potassium sulfate is 40∶3.6283.

[0183] An alkali-activated cementitious material, which is basically the same as that in Example 8, except that in Comparative Example 7, the mass of potassium sulfate is 3.6283 g.

[0184] The alkali-activated cementitious material prepared in Comparative Example 7 is named S1.5P3.2.

[0185] Figure 3 It is the compressive strength result graph of the alkali-activated cementitious materials (S1.5P0.4, S1.5P0.8, S1.5P1.6, S1.5P3.2) prepared in Examples 8 - 11 of the present invention and the alkali-activated cementitious material (S1.5P0) prepared in Comparative Example 3. As can be seen from Figure 3 it:

[0186] The alkali-activated cementitious material (S1.5P0.4) prepared in Example 8 of the present invention has a compressive strength of 26.79 MPa after 7 days of curing and a compressive strength of 31.42 MPa after 28 days of curing.

[0187] The alkali-activated cementitious material (S1.5P0.8) prepared in Example 9 of the present invention has a compressive strength of 29.83 MPa after 7 days of curing and a compressive strength of 30.69 MPa after 28 days of curing.

[0188] The alkali-activated cementitious material (S1.5P1.6) prepared in Example 10 of the present invention has a compressive strength of 32.71 MPa after 7 days of curing and a compressive strength of 30.41 MPa after 28 days of curing.

[0189] The alkali-activated cementitious material (S1.5P3.2) prepared in Example 11 of the present invention has a compressive strength of 39.0 MPa after 7 days of curing and a compressive strength of 41.37 MPa after 28 days of curing.

[0190] The alkali-activated cementitious material (S1.5P0) prepared in Comparative Example 3 has a compressive strength of 19.49 MPa after 7 days of curing and a compressive strength of 21.48 MPa after 28 days of curing.

[0191] The results show that: The alkali-activated cementitious material (S1.5P3.2) prepared in Example 11 of the present invention has the best compressive strength after 7 days and 28 days of curing, with compressive strengths of 39 MPa and 41.37 MPa respectively after 7 days and 28 days of curing. However, the compressive strengths of the alkali-activated cementitious material (S1.5P0) are only 19.49 MPa and 21.48 MPa respectively after 7 days and 28 days of curing. By comparison, it can be seen that: The alkali activator of the present invention can significantly improve the compressive strength of the cementitious material, and the compressive strength of the cementitious material increases with the increase of the addition amount of potassium peroxymonosulfate.

[0192] Figure 4Compressive strength results graph of the alkali-activated cementitious materials (S1.5P0, S1.5P0.4, S1.5P0.8, S1.5P1.6, S1.5P3.2) prepared in Examples 8 - 11 and Comparative Examples 3 - 7 of the present invention. From Figure 4 it can be seen that:

[0193] The compressive strength of the alkali-activated cementitious material (S1.5P0.4) prepared in Example 8 of the present invention is 26.79 MPa after 7 days of curing.

[0194] The compressive strength of the alkali-activated cementitious material (S1.5P0.8) prepared in Example 9 of the present invention is 29.83 Mpa after 7 days of curing.

[0195] The compressive strength of the alkali-activated cementitious material (S1.5P1.6) prepared in Example 10 of the present invention is 32.71 MPa after 7 days of curing.

[0196] The compressive strength of the alkali-activated cementitious material (S1.5P3.2) prepared in Example 11 of the present invention is 39.0 MPa after 7 days of curing.

[0197] However, the compressive strength of the alkali-activated cementitious material (S1.5P0) prepared in Comparative Example 3 is 19.49 MPa after 7 days of curing. The compressive strength of the alkali-activated cementitious material (S1.5P0.4) prepared in Comparative Example 4 is 22.81 MPa after 7 days of curing. The compressive strength of the alkali-activated cementitious material (S1.5P0.8) prepared in Comparative Example 5 is 27.33 MPa after 7 days of curing. The compressive strength of the alkali-activated cementitious material (S1.5P1.6) prepared in Comparative Example 6 is 28.73 MPa after 7 days of curing. The compressive strength of the alkali-activated cementitious material (S1.5P3.2) prepared in Comparative Example 7 is 30.43 MPa after 7 days of curing.

[0198] The results show that: The alkali-activated cementitious material (S1.5P3.2) prepared in Example 11 of the present invention has the best compressive strength of 39.0 MPa after 7 days of curing. However, the compressive strength of the alkali-activated cementitious material prepared in Comparative Example 7 is only 30.43 MPa after 7 days of curing. By comparison, it can be seen that the compressive strength of the alkali-activated cementitious material prepared based on persulfate is significantly higher than that of the alkali-activated cementitious material prepared based on potassium sulfate, and the alkali-activator used in the preparation process of the alkali-activated cementitious material based on persulfate and the alkali-activated cementitious material based on potassium sulfate contains the same molar mass of SO2- 4, indicating that the increase in the compressive strength of the alkali-activated cementitious material prepared based on persulfate is mainly caused by the addition of persulfate.

[0199] Example 12

[0200] An alkali activator, comprising persulfate and an alkaline agent.

[0201] In this embodiment, the mass ratio of persulfate to the alkaline agent is 0.1:0.36.

[0202] In this embodiment, the alkali activator further comprises a solvent, and the solvent is water, wherein the mass ratio of persulfate to water is 0.2:9.

[0203] In this embodiment, the persulfate is potassium hydrogen persulfate, and the alkaline agent is sodium hydroxide.

[0204] An alkali-activated cementitious material, comprising the following raw material components: the alkali activator in the above-mentioned embodiment and industrial solid waste containing aluminosilicate substances, wherein the mass ratio of industrial solid waste to persulfate is 1:0.01.

[0205] In this embodiment, industrial solid waste containing aluminosilicate substances is used as a precursor, and potassium hydrogen persulfate and sodium hydroxide are used as effective components of the alkali activator.

[0206] In this embodiment, the industrial solid waste used is slag and fly ash, and the mass ratio of the two is 4:1.

[0207] A preparation method of the alkali-activated cementitious material in the above-mentioned embodiment, comprising the following steps:

[0208] (1) By mass percentage, 8 g of fly ash solid, 18 g of water and 0.4 g of potassium hydrogen persulfate are mixed and stirred for 10 min to obtain a mixed turbid liquid.

[0209] (2) In the mixed turbid liquid obtained in step (1), 32 g of slag and 1.44 g of sodium hydroxide are added according to mass percentage for uniform mixing to obtain a solid waste-alkali activator mixed slurry.

[0210] (3) Transfer the mixed slurry obtained in step (2) into a 20×20×20 mm six-connected steel mold for molding. After scraping the excess slurry on the surface of the mold, cover it with a plastic wrap.

[0211] (4) The sample molded in step (3) is cured at room temperature for 24 h and then demolded, and then cured at ambient temperature and humidity until 7 days and 28 days to obtain an alkali-activated cementitious material, named S2P0.4.

[0212] Comparative Example 8

[0213] A preparation method of an alkali-activated cementitious material is basically the same as that in Example 12, except that: persulfate is not added in Comparative Example 8.

[0214] The alkali-activated cementitious material prepared in Comparative Example 8 is named S2P0.

[0215] Example 13

[0216] An alkali activator, which is basically the same as that in Example 12, except that: in Example 13, the mass ratio of persulfate to alkaline agent is 0.1∶0.18; the mass ratio of persulfate to water is 0.4∶9.

[0217] An alkali-activated cementitious material, which is basically the same as that in Example 12, except that: in Example 13, the mass ratio of industrial solid waste to persulfate is 1∶0.02.

[0218] A preparation method of an alkali-activated cementitious material, which is basically the same as that in Example 12, except that: in Example 13, the mass of potassium hydrogen persulfate is 0.8 g.

[0219] The alkali-activated cementitious material prepared in Example 13 is named S2P0.8.

[0220] Example 14

[0221] An alkali activator, which is basically the same as that in Example 12, except that: in Example 14, the mass ratio of persulfate to alkaline agent is 1∶0.9; the mass ratio of persulfate to water is 0.8∶9.

[0222] An alkali-activated cementitious material, which is basically the same as that in Example 12, except that: in Example 14, the mass ratio of industrial solid waste to persulfate is 1∶0.04.

[0223] A preparation method of an alkali-activated cementitious material, which is basically the same as that in Example 12, except that: in Example 14, the mass of potassium hydrogen persulfate is 1.6 g.

[0224] The alkali-activated cementitious material prepared in Example 14 is named S2P1.6.

[0225] Example 15

[0226] An alkali activator, which is basically the same as that in Example 12, except that: in Example 15, the mass ratio of persulfate to alkaline agent is 2∶0.9; the mass ratio of persulfate to water is 1.6∶9.

[0227] An alkali-activated cementitious material, which is basically the same as that in Example 12, except that: in Example 15, the mass ratio of industrial solid waste to persulfate is 1∶0.08.

[0228] A preparation method of an alkali-activated cementitious material, which is basically the same as that in Example 12, except that: in Example 15, the mass of potassium hydrogen persulfate is 3.2 g.

[0229] The alkali-activated cementitious material prepared in Example 15 is named S2P3.2.

[0230] Figure 5 This is a graph showing the compressive strength results of the alkali-activated cementitious materials (S2P0.4, S2P0.8, S2P1.6, S2P3.2) prepared in Examples 12 - 15 of the present invention and the alkali-activated cementitious material (S2P0) prepared in Comparative Example 8. From Figure 5 it can be seen that:

[0231] The compressive strength of the alkali-activated cementitious material (S2P0.4) prepared in Example 12 of the present invention is 27.06 MPa after 7 days of curing and 28.41 MPa after 28 days of curing.

[0232] The compressive strength of the alkali-activated cementitious material (S2P0.8) prepared in Example 13 of the present invention is 39.34 MPa after 7 days of curing and 30.41 MPa after 28 days of curing.

[0233] The compressive strength of the alkali-activated cementitious material (S2P1.6) prepared in Example 14 of the present invention is 38.68 MPa after 7 days of curing and 31.62 MPa after 28 days of curing.

[0234] The compressive strength of the alkali-activated cementitious material (S2P3.2) prepared in Example 15 of the present invention is 44.73 MPa after 7 days of curing and 41.28 MPa after 28 days of curing.

[0235] The compressive strength of the alkali-activated cementitious material (S2P0) prepared in Comparative Example 8 is 25.02 MPa after 7 days of curing and 23.3 MPa after 28 days of curing.

[0236] The results show that: The alkali-activated cementitious material (S2P3.2) prepared in Example 15 of the present invention has the best compressive strength at 7 days and 28 days, with compressive strengths of 44.73 MPa and 41.28 MPa after 7 days and 28 days of curing respectively. However, the compressive strengths of the alkali-activated cementitious material (S2P0) are only 25.02 MPa and 23.3 MPa after 7 days and 28 days of curing respectively. By comparison, it can be seen that: The alkali activator of the present invention can significantly improve the compressive strength of the cementitious material and increases with the increase in the addition amount of potassium hydrogen persulfate.

[0237] Example 16

[0238] An alkali activator comprising persulfate and an alkaline agent.

[0239] In this example, the mass ratio of persulfate to the alkaline agent is 0.1∶0.72.

[0240] In this embodiment, the alkali activator further includes a solvent, which is water. The mass ratio of persulfate to water is 0.2∶9.

[0241] In this embodiment, the persulfate is potassium hydrogen persulfate, and the alkaline agent is sodium hydroxide.

[0242] An alkali-activated cementitious material includes the following raw material components: the alkali activator in the above-mentioned embodiment and industrial solid waste containing aluminosilicate substances, where the mass ratio of industrial solid waste to persulfate is 1∶0.01.

[0243] In this embodiment, the industrial solid waste containing aluminosilicate substances is used as the precursor, and potassium hydrogen persulfate and sodium hydroxide are used as the effective components of the alkali activator.

[0244] In this embodiment, the industrial solid waste used is slag and fly ash, and the mass ratio of the two is 4∶1.

[0245] A preparation method of the alkali-activated cementitious material in the above-mentioned embodiment includes the following steps:

[0246] (1) By mass percentage, 8 g of fly ash solid, 18 g of water, and 0.4 g of potassium hydrogen persulfate are mixed and stirred for 10 min to obtain a mixed turbid liquid.

[0247] (2) In the mixed turbid liquid obtained in step (1), 32 g of slag and 2.88 g of sodium hydroxide are added according to mass percentage for uniform mixing to obtain a solid waste-alkali activator mixed slurry.

[0248] (3) The mixed slurry obtained in step (2) is transferred to a 20×20×20 mm six-compartment steel mold for molding. After scraping off the excess slurry on the surface of the mold, it is covered with a plastic wrap.

[0249] (4) The sample formed by pouring in step (3) is cured at room temperature for 24 h and then demolded, and then cured at ambient temperature and humidity until 7 days and 28 days to obtain a persulfate / alkali-activated cementitious material, named S4P0.4.

[0250] Comparative Example 9

[0251] A preparation method of an alkali-activated cementitious material is basically the same as that in Example 16, except that: in Comparative Example 9, no persulfate is added.

[0252] The alkali-activated cementitious material prepared in Comparative Example 9 is named S4P0.

[0253] Example 17

[0254] An alkali activator, which is basically the same as that in Example 16, except that: in Example 17, the mass ratio of persulfate to alkaline agent is 0.1∶0.36; the mass ratio of persulfate to water is 0.4∶9.

[0255] An alkali-activated cementitious material, which is basically the same as that in Example 16, except that: in Example 17, the mass ratio of industrial solid waste to persulfate is 1∶0.02.

[0256] A preparation method of an alkali-activated cementitious material, which is basically the same as that in Example 16, except that: in Example 17, the mass of potassium hydrogen persulfate is 0.8 g.

[0257] The alkali-activated cementitious material prepared in Example 17 is named S4P0.8.

[0258] Example 18

[0259] An alkali activator, which is basically the same as that in Example 16, except that: in Example 18, the mass ratio of persulfate to alkaline agent is 0.1∶0.18; the mass ratio of persulfate to water is 0.8∶9.

[0260] An alkali-activated cementitious material, which is basically the same as that in Example 16, except that: in Example 18, the mass ratio of industrial solid waste to persulfate is 1∶0.04.

[0261] A preparation method of an alkali-activated cementitious material, which is basically the same as that in Example 16, except that: in Example 18, the mass of potassium hydrogen persulfate is 1.6 g.

[0262] The alkali-activated cementitious material prepared in Example 18 is named S4P1.6.

[0263] Example 19

[0264] An alkali activator, which is basically the same as that in Example 16, except that: in Example 19, the mass ratio of persulfate to alkaline agent is 0.1∶0.09; the mass ratio of persulfate to water is 1.6∶9.

[0265] An alkali-activated cementitious material, which is basically the same as that in Example 16, except that: in Example 18, the mass ratio of industrial solid waste to persulfate is 1∶0.08.

[0266] A preparation method of an alkali-activated cementitious material, which is basically the same as that in Example 16, except that: in Example 19, the mass of potassium hydrogen persulfate is 3.2 g.

[0267] The alkali-activated cementitious material prepared in Example 19 is named S4P3.2.

[0268] Figure 6 Compressive strength results graph of the alkali-activated cementitious materials (S4P0.4, S4P0.8, S4P1.6, S4P3.2) prepared in Examples 16 - 19 of the present invention and the alkali-activated cementitious material (S4P0) prepared in Comparative Example 9. From Figure 6 it can be seen that:

[0269] The compressive strength of the alkali-activated cementitious material (S4P0.4) prepared in Example 16 of the present invention is 26.83 MPa after 7 days of curing and 38.6 MPa after 28 days of curing.

[0270] The compressive strength of the alkali-activated cementitious material (S4P0.8) prepared in Example 17 of the present invention is 35.08 MPa after 7 days of curing and 39.1 MPa after 28 days of curing.

[0271] The compressive strength of the alkali-activated cementitious material (S4P1.6) prepared in Example 18 of the present invention is 35.74 MPa after 7 days of curing and 40.78 MPa after 28 days of curing.

[0272] The compressive strength of the alkali-activated cementitious material (S4P3.2) prepared in Example 19 of the present invention is 42.77 MPa after 7 days of curing and 45.28 MPa after 28 days of curing.

[0273] The compressive strength of the alkali-activated cementitious material (S4P0) prepared in Comparative Example 9 is 28.09 MPa after 7 days of curing and 38.57 MPa after 28 days of curing.

[0274] The results show that: the alkali-activated cementitious material (S4P3.2) prepared in Example 19 of the present invention has the best compressive strength after 7 days and 28 days of curing, and the compressive strengths after 7 days and 28 days of curing are 42.77 MPa and 45.28 MPa respectively. However, the compressive strengths of the alkali-activated cementitious material (S4P0) after 7 days and 28 days of curing are only 28.09 MPa and 38.57 MPa respectively. By comparison, it can be seen that: the alkali activator of the present invention can significantly improve the compressive strength of the cementitious material and increases with the increase of the addition amount of potassium monopersulfate.

[0275] As can be seen from the above results, the alkali-activated cementitious material prepared by the alkali activator of the present invention can significantly improve the compressive strength. The reason is that the introduction of persulfate can not only promote the depolymerization and dissolution of solid waste raw materials into silicon-aluminum monomers, but also promote the polymerization reaction between silicon-aluminum monomers, forming more hydration products and obtaining an alkali-activated cementitious material with higher strength. At the same time, the introduction of persulfate can promote the interlaced growth between hydration products to form a cross-linked network structure, and the hydration products can fill the pores between materials to form a dense structure, thereby improving the mechanical properties of the materials.

[0276] Example 20

[0277] To investigate the promoting effect of persulfate on the depolymerization and dissolution process in alkali-activated cementitious materials, the following steps are included:

[0278] (1) Weigh 0.8 g of slag, 0.2 g of fly ash and 0.4 g of persulfate (potassium hydrogen persulfate), add them to 50 mL of deionized water, and stir magnetically for 30 min to obtain a mixed liquid.

[0279] (2) Add 3.0 g of sodium hydroxide to the mixed liquid obtained in step (1), and react under magnetic stirring to obtain a reaction system, named S1.5P1.

[0280] (3) Every 30 min, draw 4 mL of the liquid in the reaction system obtained in step (2), filter it through a 0.22 μm filter head, and finally detect the concentrations of Si and Al in the filtrate on an inductively coupled plasma spectroscopy instrument.

[0281] Comparative Example 10

[0282] To investigate the promoting effect of alkaline agents on the depolymerization and dissolution process in alkali-activated cementitious materials without adding persulfate, the following steps are included:

[0283] (1) Weigh 0.8 g of slag and 0.2 g of fly ash, add them to 50 mL of deionized water, and stir magnetically for 30 min to obtain a mixed liquid.

[0284] (2) Add 3.0 g of sodium hydroxide to the mixed liquid obtained in step (1), and react under magnetic stirring to obtain a reaction system, named S1.5P0.

[0285] (3) Every 30 min, draw 4 mL of the liquid in the reaction system obtained in step (2), filter it through a 0.22 μm filter head, and finally detect the concentrations of Si and Al in the filtrate on an inductively coupled plasma spectroscopy instrument.

[0286] Example 21

[0287] The promotion effect of persulfate on the depolymerization and dissolution processes in alkali-activated cementitious materials was investigated, including the following steps:

[0288] (1) Weigh 0.8 g of slag, 0.2 g of fly ash, and 0.8 g of persulfate (potassium hydrogen persulfate), add them to 50 mL of deionized water, and stir magnetically for 30 min to obtain a mixed liquid.

[0289] (2) Add 3.0 g of sodium hydroxide to the mixed liquid obtained in step (1), and react under magnetic stirring to obtain a reaction system, named S1.5P2.

[0290] (3) Every 30 min, draw 4 mL of the liquid from the reaction system obtained in step (2), filter it through a 0.22-μm filter head, and finally detect the concentrations of Si and Al in the filtrate on an inductively coupled plasma spectroscopy instrument.

[0291] Example 22

[0292] The promotion effect of persulfate on the depolymerization and dissolution processes in alkali-activated cementitious materials was investigated, including the following steps:

[0293] (1) Weigh 0.8 g of slag, 0.2 g of fly ash, and 1.6 g of persulfate (potassium hydrogen persulfate), add them to 50 mL of deionized water, and stir magnetically for 30 min to obtain a mixed liquid.

[0294] (2) Add 3.0 g of sodium hydroxide to the mixed liquid obtained in step (1), and react under magnetic stirring to obtain a reaction system, named S1.5P4.

[0295] (3) Every 30 min, draw 4 mL of the liquid from the reaction system obtained in step (2), filter it through a 0.22-μm filter head, and finally detect the concentrations of Si and Al in the filtrate on an inductively coupled plasma spectroscopy instrument.

[0296] Example 23

[0297] The promotion effect of persulfate on the depolymerization and dissolution processes in alkali-activated cementitious materials was investigated, including the following steps:

[0298] (1) Weigh 0.8 g of slag, 0.2 g of fly ash, and 3.2 g of persulfate (potassium hydrogen persulfate), add them to 50 mL of deionized water, and stir magnetically for 30 min to obtain a mixed liquid.

[0299] (2) Add 3.0 g of sodium hydroxide to the mixed liquid obtained in step (1), and react under magnetic stirring to obtain a reaction system, named S1.5P8.

[0300] (3) Every 30 min, 4 mL of the liquid in the reaction system obtained in step (2) is aspirated, filtered through a 0.22-μm filter head, and finally the concentrations of Si and Al in the filtrate are detected on an inductively coupled plasma spectroscopy instrument.

[0301] Figure 7 It is the relationship diagram of time-dissolution concentration corresponding to the solid waste dissolution process in the persulfate / alkali activation reaction system (S1.5P1, S1.5P2, S1.5P4, S1.5P8) constructed based on persulfate and alkaline agents in Examples 20-23 of the present invention and the alkali activation reaction system (S1.5P0) constructed based on alkaline agents in Comparative Example 10. Figure 7 Among them, (a) is the relationship diagram of time-dissolution concentration of Al, and (b) is the relationship diagram of time-dissolution concentration of Si. As can be seen from Figure 7 It can be seen that:

[0302] In Example 20 of the present invention, for the persulfate / alkali activation reaction system (S1.5P1) constructed based on persulfate and alkaline agents, the dissolution concentration of Al is 95.15 mg / L and the dissolution concentration of Si is 223.46 mg / L after 120 min of reaction.

[0303] In Example 21 of the present invention, for the persulfate / alkali activation reaction system (S1.5P2) constructed based on persulfate and alkaline agents, the dissolution concentration of Al is 166.09 mg / L and the dissolution concentration of Si is 234.02 mg / L after 120 min of reaction.

[0304] In Example 22 of the present invention, for the persulfate / alkali activation reaction system (S1.5P4) constructed based on persulfate and alkaline agents, the dissolution concentration of Al is 197.30 mg / L and the dissolution concentration of Si is 252.29 mg / L after 120 min of reaction.

[0305] In Example 23 of the present invention, for the persulfate / alkali activation reaction system (S1.5P8) constructed based on persulfate and alkaline agents, the dissolution concentration of Al is 183.73 mg / L and the dissolution concentration of Si is 215.97 mg / L after 120 min of reaction.

[0306] In the alkali activation reaction system (S1.5P0) of Comparative Example 10, the dissolution concentration of Al is 24.97 mg / L and the dissolution concentration of Si is 143.61 mg / L after 120 min of reaction.

[0307] The results show that: in the persulfate / alkali activation reaction system (S1.5P4) based on persulfate and alkaline agents in Example 22 of the present invention, the dissolution concentrations of Al and Si are the highest. After 120 minutes of reaction, the dissolution concentrations of Al and Si are 197.30 mg / L and 252.29 mg / L respectively. However, in the alkali activation reaction system (S1.5P0), the dissolution concentrations of Al and Si are 24.97 mg / L and 143.61 mg / L respectively after 120 minutes of reaction. By comparison, it can be seen that the persulfate / alkali activation reaction system based on persulfate and alkaline agents of the present invention can significantly promote the dissolution of solid waste and increases with the increase of the addition amount of potassium hydrogen persulfate.

[0308] In addition, when an alkali activator composed of potassium sulfate and 5 mol / L NaOH is used to treat industrial solid waste, after 60 minutes of leaching, the dissolution concentration of Al is about 45 mg / L and the dissolution concentration of Si is about 75 mg / L. However, in Example 22, after 60 minutes of leaching under the condition of a similar sulfate molar concentration, the dissolution concentration of Al is 185.04 mg / L and the dissolution concentration of Si is 247.25 mg / L.

[0309] From the above results, it can be seen that in the alkali activator of the present invention, the introduction of persulfate can promote the breaking of silicon-oxygen bonds and aluminum-oxygen bonds, and the solid waste raw materials are depolymerized and dissolved into silicon-aluminum monomers, thereby significantly improving the compressive strength.

[0310] Based on the above results, compared with the conventional alkali activator, the alkali activator of the present invention, under the combined action of persulfate and alkaline agents, can rapidly activate aluminosilicate substances in industrial solid waste under the condition of low alkali concentration, and has the advantages of fast activation rate and good activation effect. At the same time, under the action of the alkali activator of the present invention, industrial solid waste rich in aluminosilicate substances can be made into an alkali-activated cementitious material with high compressive strength.

[0311] The above embodiments are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, improvements and refinements should also be regarded as within the protection scope of the present invention.

Claims

1. An alkali activator for alkali-activated gelling material, characterized in that: The alkaline activator includes persulfate and alkaline agent; the mass ratio of the persulfate to the alkaline agent is 0.4-2.4:0.4-3; the alkaline agent is at least one of sodium hydroxide, sodium silicate, potassium hydroxide, calcium hydroxide and calcium oxide.

2. The base activator according to claim 1, characterized in that The alkaline activator also includes a solvent; the solvent is water; the mass ratio of the persulfate to water is 0.1-3.2:18-50; the persulfate is at least one of potassium hydrogen persulfate, sodium hydrogen persulfate, sodium persulfate, and potassium persulfate.

3. An alkali-activated gelling material, characterized in that: The raw material of the alkali-activated gelling material includes the alkali activator according to claim 1 or 2.

4. The alkali-activated gelling material according to claim 3, characterized in that: The raw materials of the alkali-activated gelling material also include industrial solid waste containing aluminum silicate substances; the mass ratio of the industrial solid waste to the persulfate is 1:0.01-0.

08.

5. The alkali-activated gelling material according to claim 4, characterized in that: The industrial solid waste includes slag and fly ash; the mass ratio of the slag to the fly ash is 4:

1.

6. A method for preparing an alkali-activated gelling material as claimed in any one of claims 3 to 5, characterized in that: The following steps are involved: S1. Mixing industrial solid waste, persulfate and water, stirring to obtain a mixed turbid liquid; S2, mixing the mixed turbid liquid obtained in step S1 with an alkaline agent to obtain a mixed slurry; S3, forming and curing the mixed slurry obtained in step S2 to obtain an alkali-activated gelling material.

7. A method for preparing an alkali-activated gelling material as claimed in claim 5, characterized in that: The following steps are involved: (1) Mix fly ash, persulfate and water, and stir to obtain a mixed turbid liquid; (2) mixing the mixed turbid liquid obtained in step (1), slag and alkaline agent to obtain a mixed slurry; (3) The mixed slurry obtained in step (2) is molded and cured to obtain an alkali-activated gelling material.

8. Use of the alkali-activated cementitious material as claimed in any one of claims 3 to 5 as cement in the construction industry.

9. Use of the alkali-activated cementitious material prepared by the preparation method according to claim 6 or 7 as cement in the construction industry.

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