A composite portland cement and a method for producing the same

Abstract

The application relates to the field of cement materials, and particularly discloses a composite Portland cement and a preparation method thereof. The composite Portland cement comprises the following raw materials in parts by weight: Portland cement 50-70 parts, fly ash 3-8 parts, polycarboxylic acid water reducing agent 0.05-0.2 parts, latex powder 10-20 parts, lightly calcined magnesium oxide 1-3 parts, bentonite 3-5 parts, calcium formate 0.5-1 part, polyacrylic acid sodium resin 0.2-0.5 part and water 10-25 parts. The composite Portland cement provided by the application improves the expansion effect of the composite Portland cement through the lightly calcined magnesium oxide and the calcium formate, and reduces the volume shrinkage phenomenon of the Portland cement in the later period. Meanwhile, the polyacrylic acid ammonium resin absorbs and locks water, and reduces the shrinkage and cracking phenomenon of the Portland cement in the later period due to the volatilization of water.

Description

Technical Field

[0001] This application relates to the field of cement materials, and more specifically, to a composite silicate cement and a method for preparing the same. Background Technology

[0002] Silicate cement sets and hardens quickly, and has high early and late strength. It is suitable for concrete construction in winter with high requirements, as well as high-strength concrete and prestressed concrete projects for important above-ground and underground structures.

[0003] However, due to the polymerization of chemical substances in silicate cement during the curing process, the cement shrinks. Cement shrinkage can easily cause building deformation, wall cracking, road deformation, and other phenomena, ultimately affecting the building's strength, reducing its load-bearing capacity, and causing collapse. Summary of the Invention

[0004] To improve the shrinkage problem of silicate cement, this application provides a composite silicate cement and its preparation method.

[0005] Firstly, this application provides a composite silicate cement, which adopts the following technical solution: A composite silicate cement comprises the following raw materials in parts by weight: 50-70 parts silicate cement, 3-8 parts fly ash, 0.05-0.2 parts polycarboxylate superplasticizer, 10-20 parts latex powder, 1-3 parts lightly calcined magnesium oxide, 3-5 parts bentonite, 0.5-1 part calcium formate, 0.2-0.5 parts sodium polyacrylate resin, and 10-25 parts water.

[0006] By employing the above technical solutions, the addition of lightly calcined magnesium oxide to the silicate cement system has a delayed expansion effect. After hydration, it expands in the later stages, coinciding with the cement's cooling and shrinkage phase. This allows the delayed expansion of lightly calcined magnesium oxide to compensate for the shrinkage of the cement, reducing the shrinkage of the composite silicate cement. Calcium formate can improve the early strength of silicate cement while having minimal impact on later strength. Furthermore, formate ions can react with cement to generate hydroxide ions, thereby accelerating the hydration of magnesium oxide, enhancing the expansion degree of lightly calcined magnesium oxide, improving its expansion stability, and reducing the shrinkage of silicate cement. The carboxyl groups on the sodium polyacrylate resin molecular chain can form hydrogen bonds with water molecules, causing water molecules to be adsorbed onto the sodium polyacrylate resin molecular chain, absorbing and locking in moisture, increasing the water content of silicate cement, and reducing cracking caused by moisture loss.

[0007] Preferably, the sodium polyacrylate resin has a particle size of 40-80 mesh.

[0008] By adopting the above technical solution, the particle size of sodium polyacrylate resin can be controlled within a reasonable range, reducing the agglomeration of sodium polyacrylate resin particles. This ensures that sodium polyacrylate resin has a good water absorption and expansion rate, and maintains the dimensional stability of silicate cement.

[0009] Preferably, the composite silicate cement raw material further includes 0.1-0.3 parts of carbon nanotubes.

[0010] By adopting the above technical solution, carbon nanotubes form a network structure in the silicate cement system, which enhances the strength and hardness of silicate cement, improves the crack resistance of the silicate cement system, and reduces the cracking phenomenon of composite silicate cement during use.

[0011] Preferably, the carbon nanotubes modify sodium polyacrylate resin, and the modification method includes the following specific steps: Carbon nanotubes are pre-acidified and dried. Then, acrylic acid and sodium hydroxide are mixed, followed by the addition of carbon nanotubes, initiator, and crosslinking agent. The mixture is then heated to react and obtain modified sodium polyacrylate resin.

[0012] By employing the above technical solution, the surface of acid-treated carbon nanotubes contains active groups such as hydroxyl and carboxyl groups. During the polymerization reaction of sodium polyacrylate, a network structure with carbon nanotubes as crosslinking points can be formed, which can increase the water absorption chain of sodium polyacrylate and enhance the water absorption effect of sodium polyacrylate resin. At the same time, carbon nanotubes can roughen the surface of sodium polyacrylate, increase the fracture surface and the micropores on the surface, and make it easier for water molecules to enter the interior of the resin, thereby increasing the water absorption rate of sodium polyacrylate and improving the expansion effect of composite silicate cement.

[0013] Preferably, the composite silicate cement raw material further includes 1-3 parts starch, 3-5 parts acrylamide, and 0.01-0.03 parts initiator.

[0014] By adopting the above technical solution, adding starch and polyacrylamide to the silicate cement system can improve the adhesion and water absorption properties of the silicate cement system, thereby increasing the water content of the composite silicate cement system and reducing the shrinkage cracking caused by the evaporation of water in the later stage of cement.

[0015] Preferably, the starch is pre-gelatinized, cooled, and then acrylamide and an initiator are added. Under nitrogen protection, a starch-polyacrylamide mixture is formed, which is then mixed, heated, and reacted. Finally, acetone is added, the mixture is filtered, and dried to obtain a starch-polyacrylamide composite resin.

[0016] By adopting the above technical solution, the polymer formed by grafting starch and polyacrylamide can double the water absorption rate of composite silicate cement and gradually release water in the later stage of silicate cement hydration, thereby improving the phenomenon of cement shrinkage and cracking.

[0017] Preferably, the bentonite is pre-impregnated with a coupling agent, then added to a starch-polyacrylamide mixture, mixed and heated to react, and then acetone is added, filtered and dried to obtain a composite resin.

[0018] By adopting the above technical solutions, bentonite can play a role in preventing leakage in composite silicate cement systems, filling the pores in the silicate cement system, improving the density of silicate cement, and reducing the occurrence of cement cracks. At the same time, after being treated with a coupling agent and then grafted with polyacrylamide, the water absorption and expansion effect of bentonite can be enhanced, thereby reducing the phenomenon of shrinkage cracking in composite silicate cement in the later stage.

[0019] Secondly, this application provides a method for preparing composite silicate cement, which adopts the following technical solution: A composite silicate cement includes the following specific steps: mixing silicate cement, fly ash, polycarboxylate superplasticizer, latex powder, lightly calcined magnesium oxide, bentonite, calcium formate, sodium polyacrylate resin and water evenly to form composite silicate cement.

[0020] By adopting the above technical solution, the prepared composite silicate cement has better water absorption and expansion effects, which can reduce the porosity of the composite silicate cement system, improve the phenomenon of shrinkage and cracking of silicate cement, and improve the dimensional stability of composite silicate cement.

[0021] In summary, this application has the following beneficial effects: 1. Because this application employs a synergistic effect of light-burned magnesium oxide and calcium formate, calcium formate can enhance the hydration degree and expansion effect of light-burned magnesium oxide in the silicate cement system, thereby improving the dimensional stability of the composite silicate cement and reducing the phenomenon of shrinkage and cracking in the later stage of silicate cement. At the same time, through the absorption and locking of moisture by ammonium polyacrylate resin, water molecules are released in the later stage of composite silicate cement, thereby reducing the phenomenon of shrinkage and cracking caused by moisture evaporation in the later stage of silicate cement.

[0022] 2. In this application, carbon nanotubes are preferably used to improve the strength and hardness of the composite silicate cement, thereby enhancing the crack resistance of the silicate cement system. Simultaneously, carbon nanotubes are grafted and crosslinked with sodium polyacrylate to form a network structure with carbon nanotubes as crosslinking points, enhancing the water absorption and expansion effect of sodium polyacrylate and improving the shrinkage cracking phenomenon of the composite silicate cement. Detailed Implementation

[0023] The present application will be further described in detail below with reference to the embodiments.

[0024] The polycarboxylate superplasticizer selected is PCE-101 type superplasticizer.

[0025] Sodium polyacrylate resin has a molecular weight of 2 million.

[0026] The average particle size of bentonite is 200 mesh. Example

[0027] Example 1 This embodiment provides a composite silicate cement comprising the following raw materials in parts by weight: 60 kg silicate cement, 5 kg fly ash, 0.12 kg polycarboxylate superplasticizer, 15 kg latex powder, 2 kg lightly calcined magnesium oxide, 4 kg bentonite, 0.8 kg calcium formate, 0.3 kg sodium polyacrylate resin, and 17 kg water. The sodium polyacrylate resin has a particle size of 50 mesh.

[0028] The preparation method of composite silicate cement includes the following specific steps: Silicate cement, fly ash, polycarboxylate superplasticizer, latex powder, bentonite, and water are mixed and stirred evenly. Then, lightly calcined magnesium oxide, bentonite, calcium formate, and sodium polyacrylate resin are added and mixed evenly to form composite silicate cement.

[0029] Example 2 The difference between Example 2 and Example 1 is that the amount of silicate cement used in the composite silicate cement raw material is 50 kg, the amount of fly ash is 8 kg, the amount of polycarboxylate superplasticizer is 0.05 kg, the amount of latex powder is 10 kg, the amount of lightly calcined magnesium oxide is 3 kg, the amount of bentonite is 5 kg, the amount of calcium formate is 1 kg, the amount of sodium polyacrylate resin is 0.2 kg, and the amount of water is 25 kg.

[0030] Example 3 The difference between Example 3 and Example 1 is that the amount of silicate cement used in the composite silicate cement raw material is 70 kg, the amount of fly ash is 3 kg, the amount of polycarboxylate superplasticizer is 0.2 kg, the amount of latex powder is 20 kg, the amount of lightly calcined magnesium oxide is 1 kg, the amount of bentonite is 3 kg, the amount of calcium formate is 0.5 kg, the amount of sodium polyacrylate resin is 0.5 kg, and the amount of water is 10 kg.

[0031] Example 4 The difference between Example 4 and Example 1 is that the composite silicate cement raw material also includes 0.2 kg of carbon nanotubes.

[0032] The preparation method of composite silicate cement includes the following specific steps: Silicate cement, fly ash, polycarboxylate superplasticizer, latex powder, bentonite, and water are mixed and stirred evenly. Then, lightly calcined magnesium oxide, carbon nanotubes, bentonite, calcium formate, and sodium polyacrylate resin are added and mixed evenly to form composite silicate cement.

[0033] Example 5 The difference between Example 5 and Example 4 is that the amount of carbon nanotubes used in the composite silicate cement raw material is 0.1 kg.

[0034] Example 6 The difference between Example 6 and Example 4 is that the amount of carbon nanotubes used in the composite silicate cement raw material is 0.3 kg.

[0035] Example 7 The difference between Example 7 and Example 4 is that carbon nanotubes in the composite silicate cement raw material modify sodium polyacrylate resin. In the modification process, the crosslinking agent is methylenebisacrylamide and the initiator is ammonium persulfate. The mass ratio of carbon nanotubes, acrylic acid, crosslinking agent and initiator is 1:20:0.01:1.

[0036] The preparation method of composite silicate cement includes the following specific steps: S1: Carbon nanotubes are immersed in a 65% nitric acid aqueous solution at 80°C for 4 hours, then rinsed with water until the rinsing solution is neutral, and then the carbon nanotubes are removed and dried to obtain acidified carbon nanotubes.

[0037] S2: Then, acrylic acid and a 30% sodium hydroxide aqueous solution are mixed, wherein the mass ratio of sodium hydroxide aqueous solution to acrylic acid is 1:1. Then, acidified carbon nanotubes, crosslinking agent and initiator are added, heated to 75°C, and reacted for 1 hour. Then, the mixture is dried, pulverized, and ground through a 50-mesh sieve to obtain modified sodium polyacrylate resin.

[0038] S3: Mix silicate cement, fly ash, polycarboxylate superplasticizer, latex powder, bentonite and water, stir evenly, then add lightly calcined magnesium oxide, carbon nanotubes, bentonite, calcium formate and modified sodium polyacrylate resin, stir evenly to form composite silicate cement.

[0039] Example 8 The difference between Example 8 and Example 7 is that the composite silicate cement raw materials also include 2 kg of starch, 4 kg of acrylamide, and 0.02 kg of initiator. The initiator is ammonium persulfate.

[0040] The preparation method of composite silicate cement includes the following specific steps: S1: Carbon nanotubes are soaked in a 65% nitric acid aqueous solution at 80°C for 4 hours, then rinsed with water until the rinsing solution is neutral. The carbon nanotubes are then removed and dried to obtain acidified carbon nanotubes. Then, acrylic acid and a 30% sodium hydroxide aqueous solution are mixed, with the mass ratio of sodium hydroxide aqueous solution to acrylic acid being 1:1. Acidified carbon nanotubes, crosslinking agent, and initiator are then added, heated to 75°C, and reacted for 1 hour. After drying, pulverizing, and grinding, the mixture is passed through a 50-mesh sieve to obtain modified sodium polyacrylate resin.

[0041] S2: Mix starch with distilled water in advance, with a mass ratio of distilled water to starch of 20:1. Heat to 80℃ and keep warm for 1 hour to gelatinize the starch. After cooling to 60℃, add acrylamide and initiator under the protection of nitrogen to form a starch-polyacrylamide mixture. React at 60℃ for 3 hours. Add acetone and stir to obtain a white precipitate. Filter, take the solid, wash and dry to obtain starch-polyacrylamide composite resin.

[0042] S3: Mix silicate cement, fly ash, polycarboxylate superplasticizer, latex powder, bentonite and water, stir evenly, then add lightly calcined magnesium oxide, carbon nanotubes, bentonite, calcium formate, modified sodium polyacrylate resin and starch-polyacrylamide composite resin and mix evenly to form composite silicate cement.

[0043] Example 9 The difference between Example 9 and Example 8 is that the amount of starch used in the composite silicate cement raw material is 1 kg, the amount of acrylamide used is 5 kg, and the amount of initiator used is 0.03 kg.

[0044] Example 10 The difference between Example 10 and Example 8 is that the amount of starch used in the composite silicate cement raw material is 3 kg, the amount of acrylamide used is 3 kg, and the amount of initiator used is 0.01 kg.

[0045] Example 11 The difference between Example 11 and Example 8 is that starch is not used in the composite silicate cement raw materials.

[0046] The preparation method of composite silicate cement includes the following specific steps: S1: Carbon nanotubes are soaked in a 65% nitric acid aqueous solution at 80°C for 4 hours, then rinsed with water until the rinsing solution is neutral. The carbon nanotubes are then removed and dried to obtain acidified carbon nanotubes. Then, acrylic acid and a 30% sodium hydroxide aqueous solution are mixed, with the mass ratio of sodium hydroxide aqueous solution to acrylic acid being 1:1. Acidified carbon nanotubes, crosslinking agent, and initiator are then added, heated to 75°C, and reacted for 1 hour. After drying, pulverizing, and grinding, the mixture is passed through a 50-mesh sieve to obtain modified sodium polyacrylate resin.

[0047] S2: Acrylamide and initiator are mixed and reacted at 60°C for 3 hours. After adding acetone and stirring, a white precipitate is obtained. The precipitate is filtered, and the solid is washed and dried to obtain polyacrylamide resin.

[0048] S3: Mix silicate cement, fly ash, polycarboxylate superplasticizer, latex powder, bentonite and water, stir evenly, then add lightly calcined magnesium oxide, carbon nanotubes, bentonite, calcium formate, modified sodium polyacrylate resin and polyacrylamide resin, stir evenly to form composite silicate cement.

[0049] Example 11 The difference between Example 11 and Example 8 is that carbon nanotubes are not used in the composite silicate cement raw materials.

[0050] The preparation method of composite silicate cement includes the following specific steps: S1: Mix starch with distilled water in advance, with a mass ratio of distilled water to starch of 20:1. Heat to 80℃ and keep warm for 1 hour to gelatinize the starch. After cooling to 60℃, add acrylamide and initiator under the protection of nitrogen to form a starch-polyacrylamide mixture. React at 60℃ for 3 hours. Add acetone and stir to obtain a white precipitate. Filter, take the solid, wash and dry to obtain starch-polyacrylamide composite resin.

[0051] S2: Mix silicate cement, fly ash, polycarboxylate superplasticizer, latex powder, bentonite and water, stir evenly, then add lightly calcined magnesium oxide, carbon nanotubes, bentonite, calcium formate, sodium polyacrylate resin and starch-polyacrylamide composite resin and mix evenly to form composite silicate cement.

[0052] Example 12 The difference between Example 12 and Example 8 is that the bentonite in the composite silicate cement raw material is grafted, and the coupling agent is KH560.

[0053] The preparation method of composite silicate cement includes the following specific steps: S1: Carbon nanotubes are soaked in a 65% nitric acid aqueous solution at 80°C for 4 hours, then rinsed with water until the rinsing solution is neutral. The carbon nanotubes are then removed and dried to obtain acidified carbon nanotubes. Then, acrylic acid and a 30% sodium hydroxide aqueous solution are mixed, with the mass ratio of sodium hydroxide aqueous solution to acrylic acid being 1:1. Acidified carbon nanotubes, crosslinking agent, and initiator are then added, heated to 75°C, and reacted for 1 hour. After drying, pulverizing, and grinding, the mixture is passed through a 50-mesh sieve to obtain modified sodium polyacrylate resin.

[0054] S2: Mix starch with distilled water in advance, with a mass ratio of distilled water to starch of 20:1. Heat to 80℃ and keep warm for 1 hour to gelatinize the starch. After cooling to 60℃, add acrylamide and initiator under the protection of nitrogen to form a starch-polyacrylamide mixture. Then, the bentonite was soaked in a 40% (w / w) coupling agent aqueous solution for 24 hours, the treated bentonite was dried, and then a starch-polyacrylamide mixture was added. The mixture was reacted at 60°C for 3 hours. After adding acetone and stirring, a white precipitate was obtained. The precipitate was filtered, and the solid was washed and dried to obtain the polyacrylamide composite resin.

[0055] S3: Mix silicate cement, fly ash, polycarboxylate superplasticizer, latex powder, bentonite and water, stir evenly, then add lightly calcined magnesium oxide, carbon nanotubes, bentonite, calcium formate, modified sodium polyacrylate resin and polyacrylamide composite resin and mix evenly to form composite silicate cement.

[0056] Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that calcium formate is not used in the composite silicate cement raw materials.

[0057] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that calcium formate and lightly calcined magnesium oxide are not used in the composite silicate cement raw materials.

[0058] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that dead-burned magnesium oxide was used instead of light-burned magnesium oxide in the composite silicate cement raw material.

[0059] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that calcium formate, lightly calcined magnesium oxide, and sodium polyacrylate resin are not used in the composite silicate cement raw materials.

[0060] Performance testing The composite silicate cements provided in Examples 1-12 and Comparative Examples 1-4 of this application were subjected to the following performance tests, and the specific test results are shown in Table 1.

[0061] Detection methods I. Expansion Rate Referring to the standard JC / T313-2009 "Test Method for Expansion Rate of Expansive Cement", the expansion rate of the composite silicate cement prepared in this application at different ages was tested at 60℃.

[0062] II. Compressive Strength Referring to the standard GB / T50081-2002 "Mechanical Properties of Ordinary Concrete", expansion specimens were formed in a 100×100×515mm mold and cured in a curing room at (20±2)℃. The compressive strength of the composite silicate cement prepared in this application after 3D and 28D of curing was tested.

[0063] Table 1: Performance Test Results Data Table The performance test results show that the composite silicate cement prepared in this application has a good expansion effect and maintains good system stability within 1-14 days, thereby improving the phenomenon of easy shrinkage after curing of conventional silicate cement. Examples 1-3 of this application enhance the expansion of the silicate cement system through the synergistic effect of lightly calcined magnesium oxide and calcium formate. Simultaneously, the use of sodium polyacrylate resin increases the water content of the composite silicate cement system, reducing the volume shrinkage caused by water evaporation in the later stages. A comparison of Comparative Examples 1, 2, and 4 with Example 1 shows that Comparative Example 1 does not use calcium formate, Comparative Example 2 does not use calcium formate and lightly calcined magnesium oxide, and Comparative Example 4 does not use calcium formate, lightly calcined magnesium oxide, and sodium polyacrylate resin. The performance test results indicate that the overall performance of the composite silicate cement decreases in all of these cases.

[0064] A comparison of Comparative Example 3 and Example 1 shows that, in Comparative Example 3, which uses dead-burned magnesia, the composite silicate cement still exhibits a certain expansion effect, as indicated by performance testing, although the expansion effect is slightly reduced. This may be because lightly calcined magnesia has higher activity, a faster expansion rate, and better structural stability.

[0065] In Examples 4-6, different amounts of carbon nanotubes were added to the composite silicate cement system. Performance tests showed that the compressive strength of the composite silicate cement significantly increased, while also exhibiting good dimensional stability and reduced shrinkage. In Example 7, surface modification of sodium polyacrylate resin with carbon nanotubes improved the expansion effect and compressive strength of the composite silicate cement. This further demonstrates that grafting carbon nanotubes onto sodium polyacrylate resin forms a network structure within the cement, increasing the molecular chains of the sodium polyacrylate resin. This facilitates the entry of water molecules into the interior of the sodium polyacrylate resin, thereby increasing the water content of the composite silicate cement and improving the shrinkage and cracking phenomenon.

[0066] In Examples 8-10, different amounts of starch and polyacrylamide were added to the composite silicate cement system. Performance tests showed that the expansion rate of the composite silicate cement reached 0.05% and 0.084% at 1D and 14D, respectively. This further demonstrates that the addition of starch and polyacrylamide grafted onto the silicate cement system can further enhance the water content of the composite silicate cement system, facilitating the release of water later and reducing the volume shrinkage caused by water evaporation. A comparison of Examples 11 and 8 shows that Example 11, without the use of carbon nanotubes, resulted in a decrease in both the expansion effect and compressive strength of the composite silicate cement. This further illustrates the modifying effect of carbon nanotubes on sodium polyacrylate resin, which also enhances the water absorption of polyacrylamide and starch. Thus, through the synergistic effect of all components, the composite silicate cement maintains good expansion stability and reduces volume shrinkage.

[0067] In Example 12, bentonite was treated with a coupling agent and then grafted with a starch-polyacrylamide polymer. Performance testing results showed that the overall performance of the composite silicate cement was further improved. Simultaneously, the bentonite exhibited better bonding with other components, further enhancing the crack resistance of the silicate cement and improving its dimensional stability.

[0068] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A composite silicate cement, characterized in that, The raw materials include the following parts by weight: 50-70 parts silicate cement, 3-8 parts fly ash, 0.05-0.2 parts polycarboxylate superplasticizer, 10-20 parts latex powder, 1-3 parts lightly calcined magnesium oxide, 3-5 parts bentonite, 0.5-1 parts calcium formate, 0.2-0.5 parts sodium polyacrylate resin, 10-25 parts water, 0.1-0.3 parts carbon nanotubes, 1-3 parts starch, 3-5 parts acrylamide, and 0.01-0.03 parts initiator. The carbon nanotubes modify sodium polyacrylate resin, and the modification method includes the following specific steps: Carbon nanotubes are pre-acidified and dried. Then, acrylic acid and sodium hydroxide are mixed, followed by the addition of carbon nanotubes, initiator, and crosslinking agent. The mixture is heated to react and obtain modified sodium polyacrylate resin. The process of pre-preparing a composite resin from starch, bentonite, and acrylamide includes the following specific steps: Starch is pre-gelatinized, cooled, and then acrylamide and an initiator are added. Under nitrogen protection, a starch-polyacrylamide mixture is formed. Bentonite is pre-impregnated with a coupling agent and then added to the starch-polyacrylamide mixture. The mixture is heated and reacted, and then acetone is added, filtered, and dried to obtain a composite resin.

2. The composite silicate cement according to claim 1, characterized in that: The sodium polyacrylate resin has a particle size of 40-80 mesh.

3. A method for preparing composite silicate cement as described in any one of claims 1-2, characterized in that: The specific steps include: mixing silicate cement, fly ash, polycarboxylate superplasticizer, latex powder, lightly calcined magnesium oxide, starch-polyacrylamide modified bentonite, calcium formate, carbon nanotube modified sodium polyacrylate resin and water evenly to form composite silicate cement.

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