Cement-based rigid waterproof material self-repairing admixture, preparation method and application thereof

Abstract

The application belongs to the technical field of building materials, and discloses a cement-based rigid waterproof material self-repairing additive, a preparation method and application thereof.The self-repairing additive comprises the following raw materials in mass fractions: 10-20 parts of beta-cyclodextrin / complexing agent inclusion compound, 15-30 parts of calcined phosphogypsum, and 50-75 parts of sodium carbonate impregnated diatomite.Through the introduction of the complexing agent into the inner cavity of the beta-cyclodextrin by the decyltrimethylammonium chloride, the beta-cyclodextrin / complexing agent inclusion compound is formed, the slow release of the complexing agent is realized, the long-term effectiveness of the self-repairing effect on the cracks is maintained, and the retardation effect of the complexing agent on the cement is avoided.The calcined phosphogypsum and the sodium carbonate impregnated diatomite provide free calcium ions and carbonate ions for the self-repairing process, and improve the complexing self-repairing effect, so that the self-repairing additive has excellent and long-acting crack self-repairing capability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of building materials, and particularly relates to a cement-based rigid waterproof material self-repairing additive, a preparation method and application thereof. BACKGROUND

[0002] Cement-based rigid waterproof materials mainly include waterproof mortar and waterproof concrete. Cement-based rigid waterproof materials have good durability and long service life, and have important application prospects in wall waterproofing and underground waterproofing engineering. However, the ability of cement-based rigid waterproof materials to adapt to deformation is poor, and cracks are easily generated to cause leakage, which limits the application thereof. In order to improve the long-term impermeability of cement-based rigid waterproof materials, the technology of adding a crack self-repairing additive to the rigid waterproof material is increasingly valued. Existing crack self-repairing additives for rigid waterproof materials mainly include microcapsules, microorganisms and complexing agents.

[0003] The action mechanism of microcapsule self-repairing is that the binder is coated in the capsule, and when cracks appear in the rigid waterproof material, the stress at the crack tip causes the capsule to break and release the binder, thereby repairing the cracks. The action mechanism of microorganism self-repairing is that calcium carbonate is generated by the reaction of microorganisms and nutrient solution to repair the cracks. Both microcapsules and microorganisms belong to consumable additives, and the self-repairing effect on cracks is difficult to be long-lasting and effective.

[0004] The action mechanism of complexing agent self-repairing is that the complexing agent reacts with free calcium ions in the rigid waterproof layer to generate calcium complexes, which migrate to the cracks with water, and the calcium complexes react with carbonate in the crack liquid to generate calcium carbonate to repair the cracks, and the complexing agent returns to its original state, can repeatedly react with free calcium ions, and realizes the self-repairing of cracks. Compared with microcapsule and microorganism self-repairing, complexing agent self-repairing has the characteristics of long-lasting and effective, and can have the same service life as the building. However, the problems of complexing agent self-repairing are as follows: first, the content of free calcium ions and carbonate in the rigid waterproof layer is limited, and carbon dioxide in the air is difficult to diffuse into the interior of the waterproof layer, resulting in that the content of carbonate in the surface cracks of the waterproof layer is relatively high, while the content of carbonate in the internal cracks is very low, and thus the self-repairing effect on the internal cracks of the waterproof layer is poor; second, the complexing agent is theoretically non-consumable and can be long-lasting and effective, but in fact it is easily dissolved in water and migrates out of the rigid waterproof layer, thereby reducing the play of the complexing agent in the self-repairing of cracks in the rigid waterproof material; third, common complexing agents (such as sodium citrate and sodium gluconate) have a strong setting retarding effect on cement, and a slight amount of addition will cause the rigid waterproof material to be difficult to set and solidify. SUMMARY

[0005] The technical problem solved by the present application is to provide a cement-based rigid waterproof material self-repairing additive, a preparation method and application thereof, aiming at the deficiencies of the existing complexing agent self-repairing technology, which has excellent and long-acting crack self-repairing ability and does not negatively affect the performance of the rigid waterproof material.

[0006] To solve the technical problem proposed in the present application, the present application provides a cement-based rigid waterproof material self-repairing additive, which comprises the following raw materials in mass fraction: 10-20 parts of β-cyclodextrin / complexing agent inclusion compound, 15-30 parts of calcined phosphogypsum, and 50-75 parts of sodium carbonate impregnated diatomite.

[0007] In the above scheme, the preparation method of the β-cyclodextrin / complexing agent inclusion compound is as follows: β-cyclodextrin is uniformly mixed with water, then decyltrimethylammonium chloride is added and heated and stirred, then the complexing agent is added and heated and stirred, followed by ultrasonic dispersion treatment, and finally the mixed solution is subjected to centrifugal spray drying to obtain the β-cyclodextrin / complexing agent inclusion compound.

[0008] Further, in the preparation process of the β-cyclodextrin / complexing agent inclusion compound, the mass fraction of each raw material is as follows: 100 parts of β-cyclodextrin, 200-300 parts of water, 10-20 parts of decyltrimethylammonium chloride, and 30-50 parts of complexing agent.

[0009] Further, the complexing agent is one or a mixture of two of sodium gluconate and sodium citrate.

[0010] Further, after the addition of the decyltrimethylammonium chloride, the heating temperature is 70-80℃, the stirring rate is 150-200rpm, and the stirring time is 20-30min.

[0011] Further, after the addition of the complexing agent, the heating temperature is 70-80℃, the stirring rate is 200-300rpm, and the stirring time is 30-40min.

[0012] Further, the ultrasonic dispersion treatment time is 10-15min.

[0013] Further, the inlet air temperature of the centrifugal spray drying is 180-200℃, and the exhaust air temperature is 80-90℃.

[0014] Further, the particle size of the β-cyclodextrin / complexing agent inclusion compound is 200-300 mesh, and the water content is ≤2%.

[0015] In the above scheme, the calcination temperature of the calcined phosphogypsum is 850-900℃, and the calcination time is 1-2h.

[0016] In the above scheme, the calcined phosphogypsum has a particle size of 200-300 mesh and a calcium sulfate content of >80%.

[0017] In the above scheme, the preparation method of the sodium carbonate impregnated diatomite is as follows:

[0018] 1) adding diatomite into hydrochloric acid, stirring and filtering to obtain pretreated diatomite;

[0019] 2) uniformly dispersing the pretreated diatomite in water, adding sodium carbonate, stirring and drying to obtain sodium carbonate impregnated diatomite.

[0020] Further, the concentration of the hydrochloric acid is 1.5-2.5 mol / L.

[0021] Further, in the preparation process of the sodium carbonate impregnated diatomite, the mass fractions of the raw materials are as follows: diatomite 50-100 parts, hydrochloric acid 5-10 parts, water 200-300 parts, and sodium carbonate 30-50 parts.

[0022] Further, the stirring rate after adding the hydrochloric acid is 100-200 rpm, and the stirring time is 20-30 min.

[0023] Further, the stirring rate after adding the sodium carbonate is 100-150 rpm, and the stirring time is 10-15 min.

[0024] Further, the drying temperature is 110-120℃, and the drying time is 2-4 h.

[0025] Further, the particle size of the sodium carbonate impregnated diatomite is 200-300 mesh, and the water content is ≤2%.

[0026] The application further provides a preparation method of the cement-based rigid waterproof material self-repairing additive, which comprises the following steps: uniformly mixing a β-cyclodextrin / complexing agent inclusion compound, calcined phosphogypsum and sodium carbonate impregnated diatomite to obtain the cement-based rigid waterproof material self-repairing additive.

[0027] The application further provides an application of the cement-based rigid waterproof material self-repairing additive, and the application method is as follows: mixing the cement-based rigid waterproof material self-repairing additive into powder of the cement-based rigid waterproof material.

[0028] In the above scheme, the addition amount of the cement-based rigid waterproof material self-repairing additive is 1-3% of the cement mass.

[0029] The technical concept of the application is as follows:

[0030] 1)The present application solves the problem of short-term effect of complexing agent and cement retarding by including the complexing agent in β-cyclodextrin, which has a special cavity structure and can include the complexing agent as a host, but the outer surface of the β-cyclodextrin is hydrophilic due to the shielding effect of C-H bond on the inner cavity. The complexing agent used in the present application is a hydrophilic substance and cannot enter the hydrophobic inner cavity of the β-cyclodextrin. To overcome this problem, decyltrimethylammonium chloride is first introduced into the inner cavity of the β-cyclodextrin to form a β-cyclodextrin / decyltrimethylammonium chloride inclusion compound, and then the electrostatic interaction between the positively charged decyltrimethylammonium chloride and the negatively charged complexing agent is used to introduce the complexing agent into the inner cavity of the β-cyclodextrin, thereby obtaining a β-cyclodextrin / complexing agent inclusion compound.

[0031] 2)The present application solves the problem of lack of free calcium ions and carbonate ions during the self-repairing of the complexing agent. On the one hand, calcined phosphogypsum is introduced, which has a high solubility in water and can increase the content of free calcium ions in the rigid waterproof material. On the other hand, sodium carbonate impregnated diatomite is introduced, which can store sodium carbonate in the pores of diatomite. When microcracks appear in the rigid waterproof layer, the sodium carbonate in the diatomite is gradually dissolved by water to play a role. However, if sodium carbonate is directly added, it will react with calcium hydroxide generated during the hydration of cement to form calcium carbonate, which will be completely consumed. However, the organic matter in diatomite blocks the pores, reducing the adsorption capacity of diatomite for sodium carbonate. Therefore, hydrochloric acid is used to remove the organic matter in the pores of diatomite to improve the adsorption capacity of diatomite for sodium carbonate, thereby providing more carbonate ions for the self-repairing of the complexing agent.

[0032] Compared with the prior art, the present application has the following advantages:

[0033] The cement-based rigid waterproof material self-repairing admixture of the present application is composed of β-cyclodextrin / complexing agent inclusion compound, calcined phosphogypsum, and sodium carbonate impregnated diatomite. The complexing agent is successfully introduced into the inner cavity of the β-cyclodextrin by decyltrimethylammonium chloride to form a β-cyclodextrin / complexing agent inclusion compound. When the inclusion compound is added to the cement-based rigid waterproof material, the complexing agent in the cavity of the β-cyclodextrin is slowly released in the form of ions, which can control the content of the complexing agent in the rigid waterproof material and maintain the long-term effectiveness of the self-repairing effect on cracks. On the other hand, it can effectively avoid the retarding effect of the complexing agent on cement, increase the amount of complexing agent, and enhance the self-repairing effect of cracks. Calcined phosphogypsum and sodium carbonate impregnated diatomite provide free calcium ions and carbonate ions, respectively, for the self-repairing process of the complexing agent, promote the formation of calcium carbonate precipitation in the cracks, and significantly improve the self-repairing effect of the complexing agent. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The surface morphology of the waterproof mortar before and after the self-repairing of the self-repairing admixture of Example 1.

[0035] Figure 2 Surface morphology of waterproof mortar before and after crack repair for adding self-repairing admixture of comparative example 1-2.

[0036] Figure 3 Surface morphology of cement mortar before and after crack repair for not adding self-repairing admixture. DETAILED DESCRIPTION

[0037] In order to better understand the present application, the content of the present application is further illustrated below in combination with examples, but the content of the present application is not limited only to the following examples.

[0038] In the following examples, the preparation method of calcined phosphogypsum is as follows:

[0039] Phosphogypsum is calcined at 860℃ for 2h, ground after cooling, and sieved through a 200 mesh screen to obtain calcined phosphogypsum with a calcium sulfate content of 88%.

[0040] In the following examples, the preparation method of sodium carbonate impregnated diatomite is as follows:

[0041] 1) 80 parts of diatomite is added to 8 parts of hydrochloric acid with a concentration of 2 mol / L, stirred at 150 rpm for 25 min, and then filtered to obtain pretreated diatomite;

[0042] 2) The pretreated diatomite is uniformly dispersed in 250 parts of water, and then 40 parts of sodium carbonate is added, stirred at a speed of 150 rpm for 12 min, and dried in an oven at 120℃ for 2h to obtain sodium carbonate impregnated diatomite with a particle size of 200 mesh and a water content of 1%.

[0043] In the following examples, the water permeability of the test piece before and after self-repairing is tested according to the crack self-repairing performance test method in T / CECS 913-2021 "Standard Test Method for Self-repairing Performance of Cement Concrete", and the self-repairing performance is evaluated. The specific steps are as follows: a Φ100mm×50mm test piece aged for 7d is loaded to precast a crack by using the splitting method, then the precast crack test piece is sleeved into the bottom of a Φ100mm×150mm rubber cylinder and fixed, 1000ml of water is poured, the time taken for the water flow to complete is recorded, and the initial water permeability of the test piece is calculated; select a test piece with an initial water permeability of 250±20ml / min, place it in a curing room for curing to 7d, 14d, 21d and 28d respectively, take it out to test the water permeability, and calculate the relative water permeability coefficient compared with the initial water permeability.

[0044] Example 1

[0045] The cement-based rigid waterproof material self-repairing additive in the embodiment comprises the following raw materials in parts by mass: 13 parts of β-cyclodextrin / complexing agent inclusion compound, 22 parts of calcined phosphogypsum, and 65 parts of sodium carbonate-impregnated diatomite. The cement-based rigid waterproof material self-repairing additive in the embodiment is obtained by uniformly mixing the above raw materials.

[0046] The preparation method of the β-cyclodextrin / complexing agent inclusion compound is as follows: 100 parts of β-cyclodextrin is uniformly mixed with 200 parts of deionized water, 10 parts of decyltrimethylammonium chloride is added, heated to 80℃, stirred at a speed of 150 rpm for 30 min, 35 parts of sodium citrate is added, and the stirring is continued at a speed of 200 rpm for 30 min at 80℃, followed by ultrasonic dispersion treatment for 12 min. Finally, the mixture is subjected to centrifugal spray drying, with the inlet air temperature controlled at 180℃ and the exhaust air temperature controlled at 80℃. The β-cyclodextrin / complexing agent inclusion compound with a particle size of 200 mesh and a water content of 1.5% is obtained.

[0047] Comparative Example 1-1

[0048] The difference between Comparative Example 1-1 and Example 1 is that the β-cyclodextrin / complexing agent inclusion compound 13 parts is replaced by sodium citrate 3.1 parts.

[0049] Comparative Example 1-2

[0050] The difference between Comparative Example 1-2 and Example 1 is that the sodium carbonate-impregnated diatomite 65 parts is replaced by sodium carbonate 21.6 parts.

[0051] Application Example 1-1

[0052] The cement-based rigid waterproof material self-repairing additive in Example 1 is applied to waterproof mortar. The raw materials are weighed according to the mass ratio in Table 1. The cement, sand, and self-repairing additive are first added to a cement mortar mixer and mixed for 30 s, and then water is added and mixed for 120 s to prepare self-repairing waterproof mortar. At the same time, the self-repairing additives in Comparative Example 1-1 and Comparative Example 1-2 are also applied to waterproof mortar for comparison, and cement mortar without self-repairing additive is prepared as a control group.

[0053] The initial and final setting times of the above mortar groups are tested, and the results are shown in Table 2. The crack self-repairing performance test is performed on the waterproof mortar mixed with Example 1 and Comparative Example 1-2 and the control group mortar according to T / CECS 913-2021 “Standard Test Methods for Self-Healing Performance of Cement Concrete”. The water permeability and relative water permeability coefficient are tested, and the results are shown in Table 3.

[0054] Table 1: Mass ratio of waterproof mortar

[0055] Raw materials Ordinary Portland cement P.O 42.5 Sand Water Self-repairing admixture Mass / g 450 1350 225 4.5

[0056] Table 2 Setting time of waterproof mortar

[0057] Sample Initial setting time (min) Final setting time (min) Example 1 360 550 Comparative Example 1-1 ＞4320 — Comparative Example 1-2 350 530 Control group 300 480

[0058] Table 3 Water permeability and relative water permeability coefficient of pre-crack waterproof mortar

[0059]

[0060] As shown in Table 2, compared with the initial and final setting time of the control mortar, the initial and final setting time of the mortar mixed with Example 1 and Comparative Examples 1-2 are increased, but the increase is very small, which does not affect the use of the mortar. However, the mortar mixed with Comparative Example 1-1 has not set after 3 days (the initial setting time is more than 4320 min), which cannot be used as a waterproof mortar. This is because sodium citrate has a strong retarding effect on the mortar, and sodium citrate coated in β-cyclodextrin does not affect the hydration of cement, and has little effect on the setting time of the mortar. However, during the later maintenance of the pre-crack mortar, the β-cyclodextrin / complexing agent inclusion compound can slowly release sodium citrate.

[0061] As shown in Table 3, the water permeability of the three waterproof mortars with the same initial water permeability is reduced with the extension of the maintenance time, but the reduction rate is: Example 1 > Comparative Example 1-2 > control group. When maintained for 28 days, the relative water permeability coefficient of the control mortar sample is 51.7%, the relative water permeability coefficient of the mortar sample mixed with Comparative Example 1-2 is 17.1%, and the relative water permeability coefficient of the mortar sample mixed with Example 1 is reduced to 0. From the attached photographs, it can be seen that the water permeability of the mortar sample mixed with Example 1 is the lowest, and the water permeability of the mortar sample mixed with Comparative Example 1-2 is higher than that of the control mortar sample. Figures 1 to 3 It can also be seen that when the crack width is 0.44 mm, after 28 days of maintenance, the crack in the mortar sample mixed with Example 1 is completely healed, the crack width in the mortar sample mixed with Comparative Example 1-2 is reduced to 0.13 mm, and the crack width in the control mortar sample is only reduced to 0.39 mm.

[0062] It can be seen that the crack self-repairing ability of the waterproof mortar test piece added with Comparative Example 1-2 is significantly higher than that of the control group mortar test piece, because the β-cyclodextrin / sodium citrate envelope in Comparative Example 1-2 releases complexing agents, which react with calcium ions in the waterproof mortar to form calcium complexes, and then migrate to the cracks with water, and react with the carbonate in the pore solution to form calcium carbonate to gradually heal the cracks. The relative water permeability coefficient of the mortar test piece added with Example 1 is significantly lower than that of the waterproof mortar test piece added with Comparative Example 1-2, and the relative water permeability coefficient of the mortar test piece added with Example 1 after 7 days of curing is close to that of the mortar test piece added with Comparative Example 1-2 after 21 days of curing, because the sodium carbonate in Comparative Example 1-2 has reacted with calcium hydroxide generated by cement hydration to form calcium carbonate during mortar mixing, and the sodium carbonate adsorbed in the pores of diatomite in the mortar added with Example 1 does not react with calcium hydroxide during mixing. During the curing process of the pre-cracked mortar test piece, the sodium carbonate in the diatomite can gradually release into the crack fluid, and then react with the calcium complexes migrated into the crack fluid to form calcium carbonate, thereby significantly enhancing the crack self-repairing ability of the waterproof mortar.

[0063] Application Example 1-2

[0064] The cement-based rigid waterproofing material self-repairing additive in Example 1 was applied to waterproof concrete, and the raw materials were weighed according to the mass ratio in Table 4. The gravel, sand, mineral powder, cement and self-repairing additive were first added to the concrete mixer and mixed for 30 s, then the water reducing agent and water were added and mixed for 120 s to prepare the self-repairing waterproof concrete. At the same time, the self-repairing additives in Comparative Example 1-1 and Comparative Example 1-2 were also applied to the waterproof concrete for comparison, and concrete without adding self-repairing additive was prepared as a control group.

[0065] The initial and final setting times of each group of concrete were tested, and the results are shown in Table 5. The crack self-repairing performance test was carried out on the waterproof concrete added with Example 1 and Comparative Example 1-2 respectively and the control group concrete according to T / CECS 913-2021 "Standard Test Methods for Self-Healing Performance of Cement Concrete", and the water permeability and relative water permeability coefficient were tested, and the results are shown in Table 6.

[0066] Table 4: Mass ratio of waterproof concrete

[0067]

[0068] Table 5: Setting time of waterproof concrete

[0069] Sample Initial setting time (min) Final setting time (min) Example 1 450 805 Comparative Example 1-1 ＞4320 — Comparative Example 1-2 460 810 Control group 430 760

[0070] Table 6: Water permeability and relative water permeability coefficient of pre-cracked waterproof concrete

[0071]

[0072] As shown in Table 5, compared with the initial and final setting time of the control concrete, the initial and final setting time of the concrete mixed with Example 1 or Comparative Examples 1-2 slightly increases, but does not affect the use, while the concrete mixed with Comparative Example 1-1 has not set for 3 days and cannot be used as waterproof concrete, which is also because sodium citrate has a strong setting retarding effect on concrete, and the sodium citrate coated in β-cyclodextrin has little effect on the setting time of concrete, but during the later curing of the pre-cracked concrete, the β-cyclodextrin / complexing agent inclusion complex can slowly release sodium citrate.

[0073] As shown in Table 6, for the three groups of concrete with basically the same initial water permeability, with the extension of curing time, the water permeability of the concrete test piece mixed with Example 1 decreases the fastest, followed by the concrete test piece mixed with Comparative Example 1-2, and the control concrete test piece decreases the slowest. When cured for 28 days, the relative water permeability coefficient of the control concrete test piece is 62.0%, the relative water permeability coefficient of the concrete test piece mixed with Comparative Example 1-2 is 19.2%, and the relative water permeability coefficient of the concrete test piece mixed with Example 1 has decreased to 0. This shows that the self-repairing admixture of Example 1 containing β-cyclodextrin / sodium citrate inclusion complex, phosphogypsum and sodium carbonate impregnated diatomite has a very good self-repairing effect on concrete cracks, and its self-repairing ability is significantly higher than that of the waterproof concrete mixed with Comparative Example 1-2 containing β-cyclodextrin / sodium citrate inclusion complex, phosphogypsum and sodium carbonate, which is also because the sodium carbonate in Comparative Example 1-2 has reacted with calcium hydroxide generated by cement hydration to form calcium carbonate during concrete mixing, and the sodium carbonate in the concrete mixed with Example 1 is not reacted with calcium hydroxide during mixing and is adsorbed in the pores of diatomite. During the curing process of the pre-cracked concrete test piece, the sodium carbonate in the diatomite can gradually release into the crack liquid, and then react with the calcium complex migrated into the crack liquid to form calcium carbonate, thereby significantly enhancing the crack self-repairing ability of the waterproof concrete.

[0074] Example 2

[0075] The cement-based rigid waterproof material self-repairing admixture in this example comprises the following raw materials in mass fraction: β-cyclodextrin / complexing agent inclusion complex 18 parts, calcined phosphogypsum 25 parts, and sodium carbonate impregnated diatomite 57 parts. The above raw materials are mixed uniformly to obtain the cement-based rigid waterproof material self-repairing admixture of this example.

[0076] The preparation method of the β-cyclodextrin / complexing agent inclusion compound is as follows: 100 parts of β-cyclodextrin is uniformly mixed with 250 parts of deionized water, 16 parts of decyltrimethylammonium chloride is added, heated to 80°C, stirred at a speed of 180 rpm for 25 min, then 40 parts of sodium gluconate is added, and the stirring is continued at 80°C and a stirring speed of 250 rpm for 25 min, followed by ultrasonic dispersion treatment for 15 min, and finally the mixture is subjected to centrifugal spray drying, with the inlet air temperature controlled at 200°C and the exhaust air temperature controlled at 90°C, to obtain a β-cyclodextrin / complexing agent inclusion compound with a particle size of 200 mesh and a water content of 1%.

[0077] Comparative Example 2-1

[0078] Comparative Example 2-1 differs from Example 2 only in that 18 parts of the β-cyclodextrin / complexing agent inclusion compound is replaced by 4.6 parts of sodium gluconate.

[0079] Comparative Example 2-2

[0080] Comparative Example 2-2 differs from Example 1 only in that 57 parts of sodium carbonate impregnated diatomite is replaced by 18.9 parts.

[0081] Application Example 2-1

[0082] The cement-based rigid waterproof material self-repairing additive in Example 2 is applied to waterproof mortar, and the raw materials are weighed according to the mass ratio in Table 7. The cement, sand and self-repairing additive are first added to a cement mortar mixer and mixed for 30 s, and then water is added and mixed for 120 s to prepare a self-repairing waterproof mortar. At the same time, the self-repairing additives in Comparative Example 2-1 and Comparative Example 2-2 are also applied to the waterproof mortar for comparison, and a cement mortar without adding a self-repairing additive is prepared as a control group.

[0083] The initial and final setting times of the above mortar groups are tested, and the results are shown in Table 8. The crack self-repairing performance test is performed on the waterproof mortar mixed with Example 2 and Comparative Example 2-2 and the control group mortar according to T / CECS 913-2021 “Standard Test Methods for Self-Healing Performance of Cement Concrete”, and the water permeability and relative water permeability coefficient are tested, and the results are shown in Table 9.

[0084] Table 7: Mass ratio of waterproof mortar

[0085]

[0086]

[0087] Table 8: Setting time of waterproof mortar

[0088] Sample Initial setting time (min) Final setting time (min) Example 2 310 480 Comparative Example 2-1 >4320 — Comparative Example 2-2 320 500 Control group 280 450

[0089] Table 9: Water permeability and relative water permeability coefficient of pre-cracked waterproof mortar

[0090]

[0091] Example 2-2

[0092] The cement-based rigid waterproofing material self-repairing admixture in Example 2 was applied to the waterproofing concrete, and the raw materials were weighed according to the mass ratio in Table 10. The gravel, sand, mineral powder, cement and self-repairing admixture were first mixed in a concrete mixer for 30 s, and then the water reducing agent and water were added and mixed for 120 s to prepare the self-repairing waterproofing concrete. At the same time, the self-repairing admixtures in Comparative Example 2-1 and Comparative Example 2-2 were also applied to the waterproofing concrete for comparison, and the concrete without adding self-repairing admixture was prepared as a control group.

[0093] The initial and final setting times of the above groups of concrete were tested, and the results are shown in Table 11. The waterproofing concrete mixed with Example 2 and Comparative Example 2-2 and the control group concrete were subjected to crack self-repairing performance test according to T / CECS 913-2021 “Standard Test Methods for Self-Healing Performance of Cement Concrete”, and the water permeability and relative water permeability coefficient were tested, and the results are shown in Table 12.

[0094] Table 10: Mass ratio of concrete

[0095]

[0096] Table 11: Setting time of waterproofing concrete

[0097] Sample Initial setting time (min) Final setting time (min) Example 2 490 890 Comparative Example 2-1 ＞4320 — Comparative Example 2-2 480 860 Control group 465 830

[0098] Table 12: Water permeability and relative water permeability coefficient of precast crack waterproofing concrete

[0099]

[0100] Example 3

[0101] The cement-based rigid waterproofing material self-repairing admixture in this example includes the following mass fractions of raw materials: β-cyclodextrin / complexing agent inclusion compound 16 parts, calcined phosphogypsum 25 parts, sodium carbonate impregnated diatomite 59 parts. The above raw materials were mixed uniformly to obtain the cement-based rigid waterproofing material self-repairing admixture of this example.

[0102] The preparation method of the β-cyclodextrin / complexing agent inclusion compound is as follows: 100 parts of β-cyclodextrin is uniformly mixed with 280 parts of deionized water, 15 parts of decyltrimethylammonium chloride is added, heated to 80°C, stirred at a speed of 200 rpm for 30 min, then 15 parts of sodium citrate and 25 parts of sodium gluconate are added, and the stirring is continued at a speed of 300 rpm for 20 min at 80°C, followed by ultrasonic dispersion treatment for 10 min, and finally the mixture is subjected to centrifugal spray drying, with the inlet air temperature controlled at 190°C and the exhaust air temperature controlled at 85°C, to obtain a β-cyclodextrin / complexing agent inclusion compound with a particle size of 300 mesh and a water content of 1.5%.

[0103] Comparative Example 3-1

[0104] Comparative Example 3-1 differs from Example 2 only in that 16 parts of the β-cyclodextrin / complexing agent inclusion compound is replaced by 1.55 parts of sodium citrate and 2.6 parts of sodium gluconate.

[0105] Comparative Example 3-2

[0106] Comparative Example 3-2 differs from Example 1 only in that 59 parts of sodium carbonate impregnated diatomite is replaced by 19.6 parts.

[0107] Application Example 3-1

[0108] The cement-based rigid waterproof material self-repairing additive in Example 3 is applied to waterproof mortar, and the raw materials are weighed according to the mass ratio in Table 13. The cement, sand and self-repairing additive are first added to a cement mortar mixer and mixed for 30 s, and then water is added and mixed for 120 s to prepare a self-repairing waterproof mortar. At the same time, the self-repairing additives in Comparative Example 3-1 and Comparative Example 3-2 are also applied to the waterproof mortar for comparison, and a cement mortar without adding a self-repairing additive is prepared as a control group.

[0109] The initial and final setting times of the above mortar groups are tested, and the results are shown in Table 14. The crack self-repairing performance test is performed on the waterproof mortar mixed with Example 3 and Comparative Example 3-2 and the control group mortar according to T / CECS 913-2021 “Standard Test Methods for Self-Healing Performance of Cement Concrete”, and the water permeability and relative water permeability coefficient are tested, and the results are shown in Table 15.

[0110] Table 13: Mass ratio of waterproof mortar

[0111] Raw materials Ordinary Portland cement P.O 42.5 Sand Water Self-repairing admixture Mass / g 450 900 225 4.5

[0112] Table 14: Setting time of waterproof mortar

[0113] Sample Initial setting time (min) Final setting time (min) Example 3 310 490 Comparative Example 3-1 ＞4320 — Comparative Example 3-2 305 510 Control group 280 450

[0114] Table 15: Water permeability and relative water permeability coefficient of pre-cracked waterproof mortar

[0115]

[0116] Example 3-2

[0117] The cement-based rigid waterproofing material self-repairing admixture in Example 3 was applied to the waterproofing concrete, and the raw materials were weighed according to the mass ratio in Table 16. The gravel, sand, mineral powder, cement and self-repairing admixture were first mixed in a concrete mixer for 30 s, and then the water reducing agent and water were added and mixed for 120 s to prepare the self-repairing waterproofing concrete. At the same time, the self-repairing admixtures in Comparative Example 3-1 and Comparative Example 3-2 were also applied to the waterproofing concrete for comparison, and the concrete without adding self-repairing admixture was prepared as a control group.

[0118] The initial and final setting times of the above groups of concrete were tested, and the results are shown in Table 17. The waterproofing concrete mixed with Example 3 and Comparative Example 3-2 and the control group concrete were subjected to crack self-repairing performance test according to T / CECS 913-2021 “Standard Test Methods for Self-Healing Performance of Cement Concrete”, and the water permeability and relative water permeability coefficient were tested, and the results are shown in Table 18.

[0119] Table 16: Mass ratio of concrete

[0120]

[0121] Table 17: Setting time of waterproofing concrete

[0122] Sample Initial setting time (min) Final setting time (min) Example 3 515 895 Comparative Example 3-1 ＞4320 — Comparative Example 3-2 500 880 Control group 485 850

[0123] Table 18: Water permeability and relative water permeability coefficient of precast crack waterproofing concrete

[0124]

[0125] The above examples are merely examples for the purpose of clear illustration, and are not a limitation on the embodiments. Based on the above description, other different forms of changes or variations can be made by those of ordinary skill in the art, and it is not necessary or possible to exhaust all embodiments, and therefore the changes or variations derived from the above are still within the protection scope of the present application.

Claims

1. A cementitious rigid waterproofing material self-repairing admixture characterized in that, The raw materials include the following mass fractions: β-cyclodextrin / complexing agent inclusion compound 10-20 parts, calcined phosphogypsum 15-30 parts, sodium carbonate impregnated diatomite 50-75 parts; The preparation method of the β-cyclodextrin / complexing agent inclusion compound is as follows: after the β-cyclodextrin is uniformly mixed with water, decyltrimethylammonium chloride is added and heated and stirred, then the complexing agent is added and heated and stirred, followed by ultrasonic dispersion treatment, and finally the mixed solution is subjected to centrifugal spray drying to obtain the β-cyclodextrin / complexing agent inclusion compound.

2. The cementitious rigid waterproofing material self-repairing admixture according to claim 1, characterized in that, In the preparation process of the β-cyclodextrin / complexing agent inclusion compound, the mass fractions of the raw materials are as follows: β-cyclodextrin 100 parts, water 200-300 parts, decyltrimethylammonium chloride 10-20 parts, and complexing agent 30-50 parts.

3. The cementitious rigid waterproofing material self-repairing admixture according to claim 1, characterized in that, The complexing agent is one of sodium gluconate and sodium citrate or a mixture of the two.

4. The cementitious rigid waterproofing material self-repairing admixture according to claim 1, characterized in that, After the addition of the decyltrimethylammonium chloride, the heating temperature is 70-80°C, the stirring rate is 150-200 rpm, and the stirring time is 20-30 min; after the addition of the complexing agent, the heating temperature is 70-80°C, the stirring rate is 200-300 rpm, and the stirring time is 30-40 min.

5. The cementitious rigid waterproofing material self-repairing admixture according to claim 1, characterized in that, The particle size of the β-cyclodextrin / complexing agent inclusion compound is 200-300 mesh, and the water content is ≤2%; the particle size of the calcined phosphogypsum is 200-300 mesh, and the calcium sulfate content is >80%; the particle size of the sodium carbonate impregnated diatomite is 200-300 mesh, and the water content is ≤2%.

6. The cementitious rigid waterproofing material self-repairing admixture according to claim 1, characterized in that, The calcination temperature of the calcined phosphogypsum is 850-900°C, and the calcination time is 1-2 h.

7. The self-healing admixture for cement-based rigid waterproofing materials according to claim 1, characterized in that, The preparation method of the sodium carbonate impregnated diatomite is as follows: 1) The diatomite is added to hydrochloric acid, stirred, and then filtered to obtain pretreated diatomite; 2) The pretreated diatomite is uniformly dispersed in water, and then sodium carbonate is added, stirred, and dried to obtain sodium carbonate impregnated diatomite.

8. The cementitious rigid waterproofing material self-repairing admixture according to claim 7, characterized in that, In the preparation process of the sodium carbonate impregnated diatomite, the mass fractions of the raw materials are as follows: diatomite 50-100 parts, hydrochloric acid 5-10 parts, water 200-300 parts, and sodium carbonate 30-50 parts.

9. A method for preparing a cementitious rigid waterproofing material self-repairing admixture according to any one of claims 1 to 8, characterized in that, The following steps are included: uniformly mixing the β-cyclodextrin / complexing agent inclusion compound, calcined phosphogypsum, and sodium carbonate impregnated diatomite to obtain a cement-based rigid waterproof material self-repairing admixture.

10. Use of the cement-based rigid waterproof material self-repairing admixture according to any one of claims 1-8 in a cement-based rigid waterproof material.

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