Premixed dry-mixed self-repairing ordinary waterproof mortar

Abstract

The invention relates to the technical field of waterproof materials for buildings, and particularly discloses premixed dry-mixed self-repairing ordinary waterproof mortar. The premixed dry-mixed self-repairing ordinary waterproof mortar is prepared from the following raw materials in parts by weight: 32 to 40 parts of Portland cement, 2 to 6 parts of silica fume, 2 to 6 parts of mineral powder, 55 to 60 parts of quartz sand, 0.05 to 0.1 part of water reducing agent, 0.07 to 0.15 part of HPMC (Hydroxy Propyl Methyl Cellulose), 0.1 to 0.2 part of defoaming agent, 1 to 2 parts of ground calcium carbonate and 6 to 10 parts of self-repairing master batch, the self-repairing master batch comprises super absorbent resin, nano active silicon and fatty acid salt. The premixed dry-mixed self-repairing common waterproof mortar provided by the invention can be used for building waterproof engineering in a complex environment, and has excellent anti-permeability and load damage crack self-repairing capability under a high permeability condition.

Description

Technical Field

[0001] The present application relates to the technical field of waterproof materials for buildings, and more specifically, to a premixed dry self-repairing ordinary waterproof mortar. Background Art

[0002] Premixed dry mortar has many advantages such as easy use, excellent quality, stable quality, material saving, energy saving and environmental protection. It can effectively reduce environmental pollution and improve project quality.

[0003] Dry-mixed ordinary waterproof mortar is a kind of premixed dry-mixed mortar. It has the advantages of waterproof and anti-seepage, good adhesion and strong durability. It is the most widely used rigid waterproof layer material. Cement-based materials such as traditional waterproof mortar are rigid waterproof materials. During use, they are easily affected by various internal and external factors such as hydration shrinkage, thermal expansion and contraction, and uneven foundation settlement, causing cracks. Although there are various measures to address cracking in the prior art, they can only minimize cracks, and it is difficult to completely suppress cracks. Once cracks occur, the waterproof mortar will lose its waterproof function.

[0004] Premixed dry self-repairing ordinary waterproof mortar is a dry mixture made of cementitious materials, dry fine aggregates, amorphous silica, active chemicals and various functional additives in a professional factory according to a certain proportion and measured and mixed. When used, once cracks occur, under the activation of water and active substances, the calcium ions and silicon ions inside the mortar will produce secondary hydration reactions to generate water-insoluble needle-shaped crystals (calcium silicate hydrate crystals CSH) to plug the cracks. The active ingredients of this material are dormant in the absence of water. Once they encounter water, the dormancy is activated and they will immediately react with water, and crystallization continues, making the mortar waterproof layer have the characteristics of "dynamic" waterproofing.

[0005] Due to the crystallization reaction between active silica and calcium in cement, the water tightness of the mortar is greatly enhanced, making the premixed dry self-repairing ordinary waterproof mortar have better waterproof and anti-seepage, durability indicators and strong crack self-repair function compared with the existing waterproof mortar, maintaining the water tightness of the mortar waterproof layer. It is especially suitable for situations where the next process may damage the mortar waterproof layer (for example, the anchoring of the insulation material in the exterior wall waterproofing process may damage the waterproof mortar layer, and rainwater will enter the inner side of the wall along the penetration channel caused by the anchoring). It solves the inherent problem of poor flexibility and easy cracking and failure of rigid waterproof materials, greatly expands the applicability and durability of waterproof mortar, and has important economic and social benefits.

[0006] With respect to the above-mentioned related technologies, the inventors found that the impermeability of the premixed dry self-repairing ordinary waterproof mortar in the prior art can mostly only meet the basic requirement of ≥0.8MPa as determined by the provisions of GB 50108-2008 "Technical Specifications for Waterproofing of Underground Engineering". However, in actual engineering applications, building structures are often affected by various complex environmental conditions, such as underground projects under complex geological conditions, basements and underground garages of high-rise buildings, underground projects in special environments such as cold areas and high-salinity areas, etc., which put forward higher requirements on the impermeability of mortar and the ability to recover from load damage under high permeability conditions. Therefore, further improving the impermeability and load damage recovery ability of premixed dry self-repairing ordinary waterproof mortar under high permeability conditions, so that it can adapt to various complex environmental conditions, is of great significance for improving the quality of building waterproofing projects. Summary of the invention

[0007] In order to improve the impermeability of premixed dry-mixed self-repairing ordinary waterproof mortar, and at the same time enhance the self-repairing ability of cracks damaged by load under high permeability conditions, the present application provides a premixed dry-mixed self-repairing ordinary waterproof mortar.

[0008] In the first aspect, the present application provides a premixed dry-mixed self-repairing ordinary waterproof mortar, adopting the following technical scheme: a premixed dry-mixed self-repairing ordinary waterproof mortar, wherein the raw materials include, by weight, 32-40 parts of silicate cement, 2-6 parts of silica fume, 2-6 parts of mineral powder, 55-60 parts of quartz sand, 0.05-0.1 parts of water reducer, 0.07-0.15 parts of HPMC, 0.1-0.2 parts of defoamer, 1-2 parts of heavy calcium carbonate and 6-10 parts of self-repairing masterbatch; the self-repairing masterbatch includes highly absorbent resin, nano-active silicon and fatty acid salt.

[0009] By adopting the above technical scheme, the premixed dry self-repairing ordinary waterproof mortar has both excellent waterproof and anti-seepage indicators and crack self-repairing ability under load damage, and can maintain the water tightness of the mortar waterproof layer for a long time. It is especially suitable for situations where uneven settlement or temperature difference may cause cracks in the main structure and then tear the mortar waterproof layer attached thereto, as well as complex geological conditions, high humidity, high salinity and alkali underground projects, etc., to improve the quality of building waterproof projects.

[0010] After being added to mortar, mineral powder and silica fume can fill the gaps between cement particles well, making the mortar denser, thereby improving the strength and anti-permeability of the mortar. In addition, silica fume can also combine with free Ca(OH)2 to form a stable calcium silicate hydrate 2CaO·SiO2·H2O, which has a higher gel strength than Ca(OH)2 crystals.

[0011] Optionally, the raw materials of the self-healing masterbatch include 2.1-3.4 parts of super absorbent resin, 0.8-2.6 parts of nano-active silicon and 3.1-4 parts of fatty acid salt, measured by weight.

[0012] By adopting the above technical scheme, highly absorbent resin, nano-active silicon and fatty acid salt can form a crystalline material when it comes into contact with water. The highly absorbent resin can quickly absorb water and expand when cracks occur, thereby blocking the cracks and preventing water from penetrating inward; the nano-active silicon generates water-insoluble crystals through a crystallization reaction with calcium ions, thereby promoting the self-repair process, further blocking the cracks, and improving the water tightness of the mortar. The nano-active silicon is in a dormant state in the absence of water, and the dormancy is activated when it comes into contact with water, and crystallization continues, giving the waterproof layer formed by the waterproof mortar a "dynamic" waterproof property.

[0013] Furthermore, the inventors found that fatty acid salt is a hydrophobic material. Compared with the addition of traditional hydrophobic agents, the use of fatty acid salt can play the role of a hydrophobic agent without affecting the strength of the mortar, reduce the penetration of water, and shorten the setting time of the mortar to a certain extent. The hydrophobic effect of fatty acid salt is manifested in that it can prevent the super absorbent resin from excessively absorbing water and maintain its expansion effect. On the other hand, it can prevent the reaction product of nano-active silicon from being eroded by water and maintain its stability, achieving a balance between hydrophobicity and water absorption of the waterproof mortar when forming a waterproof protective layer, and enhancing the self-repairing ability of the waterproof mortar under load damage under high permeability conditions.

[0014] Optionally, the highly water-absorbent resin is a terpolymer of acrylamide-acrylonitrile-acrylic acid and a starch-acrylonitrile graft copolymer in a mass ratio of 1:(0.3-0.6).

[0015] By adopting the above technical scheme, the acrylamide-acrylonitrile-acrylic acid terpolymer provides good hydrophilicity and water absorption, while the starch-acrylonitrile graft copolymer provides additional hydrophilic groups, which enhances the water absorption capacity of the super absorbent resin. The three-dimensional network structure formed by the mixture can absorb and retain moisture more effectively, while enhancing the impermeability of the waterproof mortar.

[0016] Furthermore, the inventors found that the non-ionic groups (such as amide groups) in the terpolymer of acrylate-acrylonitrile-acrylic acid and the hydrophilic groups (such as hydroxyl groups) in the starch-acrylonitrile graft copolymer work synergistically to improve the salt resistance of the super absorbent resin while maintaining good water absorption. These groups can form hydrogen bonds with water molecules and reduce the sensitivity of the super absorbent resin to salt water, which enhances the stability and durability of the waterproof mortar in the complex environment of high saline-alkali areas.

[0017] Optionally, the fatty acid salt is selected from any one or more combinations of sodium stearate, calcium stearate and potassium stearate.

[0018] Optionally, the method for preparing the nano-active silicon comprises the following steps: Add the coupling agent to ethanol, stir evenly, and prepare a 5-10% coupling agent solution; Add nano-silicon dioxide to the coupling agent solution, conduct ultrasonic dispersion reaction at 55-75°C for 5-6h, centrifuge, wash and then vacuum dry at 60-80°C to obtain; The coupling agent is selected from any one or more combinations of 3-aminopropyltriethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, γ-(phosphate)propyltrimethoxysilane and bis(2,3-epoxypropyl)phosphate.

[0019] By adopting the above technical scheme, 3-aminopropyltriethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, γ-(phosphate)propyltrimethoxysilane and bis(2,3-epoxypropyl)phosphate can react with nano-silica and calcium ions at the same time.

[0020] The nano-active silicon obtained by surface modification with a coupling agent has better dispersibility, can be uniformly adsorbed on the surface of a high molecular weight super absorbent resin, and is uniformly distributed in the waterproof mortar. Further, the inventors found that one end of the coupling agent contains a group that can react with the hydroxyl group on the surface of the nano-silicon dioxide, such as a silane group and an epoxy group, and the other end contains a group that can coordinate with calcium ions, such as an amino group, a phosphate group, and a carboxyl group, which significantly enhances the reactivity of the nano-active silicon and promotes the reaction between the nano-active silicon and the calcium ions, so that the crystals generated by the two in contact with water have higher strength and stability, further enhancing the water tightness of the mortar, so that the waterproof mortar can maintain structural stability under high permeability, and has a more excellent self-repairing ability of cracks damaged by load.

[0021] Optionally, the coupling agent is γ-(phosphate)propyltrimethoxysilane coupling agent.

[0022] By adopting the above technical solution, the γ-(phosphate)propyltrimethoxysilane coupling agent has a better self-repairing ability of load-damaged cracks under high permeability conditions than 3-aminopropyltriethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane and bis(2,3-epoxypropyl)phosphate as coupling agents.

[0023] This is because the γ-(phosphate)propyltrimethoxysilane coupling agent has a higher reactivity and can condense with the hydroxyl groups on the surface of nano-silica in a shorter time to form a stable chemical bond, effectively grafted to the surface of nano-silica, and improve the reactivity of nano-silica. It can also form a strong coordination bond through the coordination reaction of phosphate groups with calcium ions to generate insoluble calcium phosphate (Ca3(PO4)2) and other crystalline products, forming a stronger interface bond, forming a denser crystal, and improving the strength and stability of the crystal.

[0024] In particular, the inventors found that the γ-(phosphate)propyltrimethoxysilane coupling agent has better hydrolysis stability and can prevent structural damage caused by hydrolysis when exposed to water, thereby ensuring that the active groups on the surface of the nano-silica can continue to react with calcium ions to form dense and stable crystals, which can be used in more complex moisture and acid-base conditions.

[0025] In addition, the Si-O-Si network formed after the hydrolysis of the siloxane group is hydrophobic and can form a hydrophobic layer on the surface and inside of the mortar to prevent water penetration. This hydrophobic layer effectively reduces the water absorption rate of the waterproof mortar and improves its anti-seepage performance.

[0026] Optionally, the quartz sand includes 35-40 parts of 40-70 mesh quartz sand and 20-23 parts of 70-120 mesh quartz sand.

[0027] By adopting the above technical solution, quartz sand as aggregate of waterproof mortar can enhance its compressive strength and wear resistance. The use of quartz sand with different particle sizes can further optimize the particle grading of the mortar and improve its density and impermeability.

[0028] Optionally, the water reducer is a polycarboxylate water reducer.

[0029] Optionally, the viscosity of the HPMC is 50000 mPa·s and the density is 0.45 g / cm 3 .

[0030] By adopting the above technical solution, polycarboxylate water-reducing agent can reduce the water-cement ratio of mortar and improve the strength and stability of mortar, while high-viscosity HPMC can effectively improve the adhesion and water retention of mortar, making it easier to handle and shape, and can effectively increase the dispersibility of polycarboxylate water-reducing agent, while also improving the adhesion of the material to the building surface.

[0031] In summary, this application has the following beneficial effects: 1. Since the present application adopts a self-repairing masterbatch, the premixed dry self-repairing ordinary waterproof mortar has both excellent waterproof and anti-seepage indicators and the ability to self-repair cracks under load damage. It can absorb water and expand and crystallize under high permeability conditions, quickly block cracks, and maintain the water tightness of the mortar waterproof layer for a long time. It is particularly suitable for situations where cracks will appear in the main structure due to uneven settlement or temperature difference, and then the mortar waterproof layer attached thereto will be torn, as well as complex geological conditions, highly humid underground projects and other environmental situations, and has important economic and social benefits.

[0032] 2. In the present application, it is preferred to use a water-crystalline material of a polymer superabsorbent resin, nano-active silicon and fatty acid salt as a self-repairing masterbatch, which can timely block cracks and prevent the inward penetration of water. At the same time, "dynamic" waterproofing is achieved through nano-active silicon, which promotes the self-repair process and further blocks cracks. Fatty acid salts as hydrophobic materials can act as a hydrophobic agent without affecting the strength of the mortar, reduce the penetration of water, and achieve a balance between the hydrophobicity and water absorption of the waterproof mortar when forming a waterproof protective layer in combination with polymer adsorption resin and nano-active silicon, thereby enhancing the self-repairing ability of the waterproof mortar under load damage under high permeability conditions.

[0033] 3. Nano-active silicon is prepared by surface grafting modification of nano-silica using γ-(phosphate)propyltrimethoxysilane as a coupling agent. The functional group at one end of the coupling agent can condense with the hydroxyl group on the surface of nano-silica and be effectively grafted to the surface of nano-silica, while the other end can undergo a strong coordination reaction with calcium ions to generate insoluble calcium phosphate and other crystalline products, which significantly promotes the reaction between nano-active silicon and calcium ions, making the generated crystals have higher strength and stability, further enhancing the water tightness of the mortar, and forming a hydrophobic layer on the surface and inside of the mortar, reducing the water absorption rate of the waterproof mortar, and improving the waterproof mortar's anti-seepage ability, so that it can have a more excellent load-damaged crack self-repair ability under high permeability conditions. DETAILED DESCRIPTION

[0034] The following examples further illustrate the present application in detail.

[0035] raw material Unless otherwise specified, the raw materials used in the examples and comparative examples of this application are all commercially available products, specifically: Portland cement, PO42.5 ordinary Portland cement; Silica fume, bulk density is 265kg / m 3 , Ph value is 7, SiO2 content> 90%; Mineral powder: S95 mineral powder, mesh size is 600 mesh, density is 2.8g / cm 3 ; HPMC, viscosity is 50000mPa·s, density is 0.45g / cm 3 ; Heavy calcium carbonate, 400 mesh; Acrylamide-acrylonitrile-acrylic acid terpolymer, CAS number is 26982-19-4; Starch-acrylonitrile grafted copolymer, the grafting rate of acrylonitrile monomer is (50±3)%; Nano-silicon dioxide, average particle size is 100nm; The water reducer is a polycarboxylate water reducer selected from Chengrui Chemical Co., Ltd., PC-1021; The defoamer is an organosilicon defoamer selected from Guangdong Nanhui New Materials Co., Ltd., CI-0560. Example

[0036] Example 1 A premixed dry self-repairing ordinary waterproof mortar, the raw materials and the amounts are shown in Table 1, wherein the highly absorbent resin is an acrylamide-acrylonitrile-acrylic acid terpolymer and a starch-acrylonitrile graft copolymer in a mass ratio of 1:0.4, the fatty acid salt is potassium stearate, the water reducer is a polycarboxylic acid water reducer, and the defoamer is a silicone defoamer.

[0037] Table 1 The preparation method of the above-mentioned premixed dry self-repairing ordinary waterproof mortar comprises the following steps: S1: adding a coupling agent to anhydrous ethanol, stirring evenly to prepare a 7% coupling agent solution, then adding nano-silica to the coupling agent solution, ultrasonically dispersing and reacting at 75° C. for 5 hours, centrifuging, washing, and vacuum drying at 80° C. to obtain nano-active silicon, wherein the coupling agent is 3-aminopropyltriethoxysilane; S2: According to the raw material formula, super absorbent resin and nano-active silicon are added into a mixer and dry-mixed for 20 minutes, and then fatty acid salt is added and dry-mixed for 45 minutes to obtain a self-repairing masterbatch of water-crystallizable material; S3: Weigh each component according to the raw material formula ratio, first add silicate cement and quartz sand into the reactor, stir evenly, then add silica fume, mineral powder and heavy calcium carbonate and stir evenly, finally add water reducer, HPMC, defoamer and self-repairing masterbatch in sequence, stir at 200r / min in the reactor for 45min, and add (15±1)% of water when using, and adjust the fluidity to about 160mm.

[0038] Example 2 A premixed dry self-repairing ordinary waterproof mortar, which is different from Example 1 in that the raw materials and amounts are as shown in Table 1, wherein the super absorbent resin is an acrylamide-acrylonitrile-acrylic acid terpolymer and a starch-acrylonitrile graft copolymer in a mass ratio of 1:0.5, and the fatty acid salt is calcium stearate.

[0039] The preparation method of the above-mentioned premixed dry self-repairing ordinary waterproof mortar comprises the following steps: S1: adding a coupling agent to anhydrous ethanol, stirring evenly to prepare a 5% coupling agent solution, then adding nano-silica to the coupling agent solution, ultrasonically dispersing and reacting at 55° C. for 6 hours, centrifuging, washing, and vacuum drying at 60° C. to obtain nano-active silicon, wherein the coupling agent is 3-aminopropyltriethoxysilane; S2: According to the raw material formula, super absorbent resin and nano-active silicon are added into a mixer and dry-mixed for 20 minutes, and then fatty acid salt is added and dry-mixed for 45 minutes to obtain a self-repairing masterbatch of water-crystallizable material; S3: Weigh each component according to the raw material formula ratio, first add silicate cement and quartz sand into the reactor, stir evenly, then add silica fume, mineral powder and heavy calcium carbonate and stir evenly, finally add water reducer, HPMC, defoamer and self-repairing masterbatch in sequence, stir at 200r / min in the reactor for 45min, and add (15±1)% of water when using, and adjust the fluidity to about 160mm.

[0040] Example 3 A premixed dry self-repairing ordinary waterproof mortar, which is different from Example 1 in that the raw materials and amounts are as shown in Table 1, wherein the highly absorbent resin is a terpolymer of acrylamide-acrylonitrile-acrylic acid and a starch-acrylonitrile graft copolymer in a mass ratio of 1:0.3, and the fatty acid salt is sodium stearate.

[0041] The preparation method of the above-mentioned premixed dry self-repairing ordinary waterproof mortar comprises the following steps: S1: adding a coupling agent to anhydrous ethanol, stirring evenly to prepare a 10% coupling agent solution, then adding nano-silica to the coupling agent solution, ultrasonically dispersing and reacting at 65° C. for 5.5 hours, centrifuging, washing, and vacuum drying at 70° C. to obtain nano-active silicon, wherein the coupling agent is 3-aminopropyltriethoxysilane; S2: According to the raw material formula, super absorbent resin and nano-active silicon are added into a mixer and dry-mixed for 20 minutes, and then fatty acid salt is added and dry-mixed for 45 minutes to obtain a self-repairing masterbatch of water-crystallizable material; S3: Weigh each component according to the raw material formula ratio, first add silicate cement and quartz sand into the reactor, stir evenly, then add silica fume, mineral powder and heavy calcium carbonate and stir evenly, finally add water reducer, HPMC, defoamer and self-repairing masterbatch in sequence, stir at 200r / min in the reactor for 45min, and add (15±1)% of water when using, and adjust the fluidity to about 160mm.

[0042] Example 4 A premixed dry self-repairing ordinary waterproof mortar is different from Example 1 in that the raw materials and amounts are as shown in Table 1, wherein the highly absorbent resin is an acrylamide-acrylonitrile-acrylic acid terpolymer and a starch-acrylonitrile graft copolymer in a mass ratio of 1:0.6, and the other steps are the same as in Example 1.

[0043] Example 5 A premixed dry self-repairing ordinary waterproof mortar is different from Example 1 in that the raw materials and amounts are as shown in Table 1, wherein the highly absorbent resin is an acrylamide-acrylonitrile-acrylic acid terpolymer and a starch-acrylonitrile graft copolymer in a mass ratio of 1:0.5, and the other steps are the same as in Example 1.

[0044] Example 6 A premixed dry-mixed self-repairing ordinary waterproof mortar, which differs from Example 1 in that in step S1 of the preparation method of the premixed dry-mixed self-repairing ordinary waterproof mortar, the coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane, and the other steps are the same as Example 1.

[0045] Example 7 A premixed dry-mixed self-repairing ordinary waterproof mortar, which differs from Example 1 in that in step S1 of the preparation method of the premixed dry-mixed self-repairing ordinary waterproof mortar, the coupling agent is γ-(phosphate)propyltrimethoxysilane, and the other steps are the same as Example 1.

[0046] Example 8 A premixed dry-mixed self-repairing ordinary waterproof mortar is different from Example 1 in that in step S1 of the preparation method of the premixed dry-mixed self-repairing ordinary waterproof mortar, the coupling agent is bis(2,3-epoxypropyl) phosphate, and the other steps are the same as Example 1.

[0047] Example 9 A premixed dry self-repairing ordinary waterproof mortar, which differs from Example 1 in that no starch-acrylonitrile graft copolymer is added, the highly absorbent resin is an acrylamide-acrylonitrile-acrylic acid terpolymer, and the other steps are the same as those in Example 1.

[0048] Example 10 A premixed dry self-repairing ordinary waterproof mortar, which differs from Example 1 in that no acrylamide-acrylonitrile-acrylic acid terpolymer is added, the highly absorbent resin is a starch-acrylonitrile graft copolymer, and the other steps are the same as those of Example 1.

[0049] Embodiment 11 A premixed dry self-repairing ordinary waterproof mortar is different from Example 1 in that 40-70 mesh quartz sand is not added, and the 40-70 mesh quartz sand in the raw material is replaced with 70-120 mesh quartz sand of equal mass, and the other steps are the same as Example 1.

[0050] Example 12 A premixed dry self-repairing ordinary waterproof mortar is different from Example 1 in that 70-120 mesh quartz sand is not added, the 70-120 mesh quartz sand in the raw material is replaced with 40-70 mesh quartz sand of equal mass, and the other steps are the same as Example 1.

[0051] Comparative Example Comparative Example 1 A premixed dry self-repairing ordinary waterproof mortar is different from Example 1 in that the preparation of nano-active silicon in step S1 is not performed, the nano-active silicon in the raw material is replaced by silica fume of equal mass, and the other steps are the same as Example 1.

[0052] Comparative Example 2 A premixed dry self-repairing ordinary waterproof mortar is different from Example 1 in that the preparation of nano-active silicon in step S1 is not performed, the nano-active silicon in the raw material is replaced by an equal mass of nano-silicon dioxide, and the other steps are the same as Example 1.

[0053] Comparative Example 3 A premixed dry self-repairing ordinary waterproof mortar is different from Example 1 in that no nano-active silicon is added, the nano-active silicon in the raw material is replaced by a highly absorbent resin of equal mass, and the other steps are the same as Example 1.

[0054] Comparative Example 4 A premixed dry self-repairing ordinary waterproof mortar is different from Example 1 in that no fatty acid salt is added, 3.1 parts of fatty acid salt in the raw materials are replaced by 0.5 parts of water repellent (Dow Corning SHP50 silicone water repellent), and the other steps are the same as Example 1.

[0055] Comparative Example 5 A premixed dry self-repairing ordinary waterproof mortar is different from Example 1 in that no fatty acid salt is added, the fatty acid salt in the raw material is replaced by a highly absorbent resin of equal mass, and the other steps are the same as Example 1.

[0056] Comparative Example 6 A premixed dry self-repairing ordinary waterproof mortar is different from Example 1 in that no fatty acid salt and nano-active silicon are added, the fatty acid salt and nano-active silicon in the raw materials are replaced by highly absorbent resin of equal mass, and the other steps are the same as Example 1.

[0057] Performance test The following relevant performance tests were carried out on a premixed dry self-repairing ordinary waterproof mortar obtained in Examples 1-12 and Comparative Examples 1-6. Each group of tests was carried out 3 times, and the average value of the 3 test results was taken as the final result, and the final result was recorded in Table 2.

[0058] 1. Referring to the relevant provisions of GB 50108-2008 "Technical Specification for Waterproofing of Underground Engineering" and DL / T 5126-2021 "Test Procedure for Polymer Modified Cement Mortar", the premixed dry self-repairing ordinary waterproof mortar of this application was tested for its anti-seepage strength. The water consumption was 16%, the water pressure was 1.5 MPa, and the test block was a cylindrical anti-seepage test block with a diameter of 70.7 mm and a height of 30 mm. The curing conditions of DL / T 5126-2021 were used for 7d and 28d respectively. It was found that the anti-seepage test blocks of Examples 1-12 of this application were not permeable under 1.5 MPa. The anti-seepage test blocks were split and their penetration height under 1.5 MPa was measured. The results are shown in Table 2.

[0059] 2. Referring to the relevant provisions of T / CECS 913-2021 "Standard for Test Methods for Self-Healing Performance of Cement Concrete", measure the load damage compressive strength recovery rate of the premixed dry self-healing ordinary waterproof mortar of this application.

[0060] Table 2 According to the performance test results of Examples 1-12 in Table 2, it can be seen that a premixed dry self-repairing ordinary waterproof mortar of the present application has excellent waterproof and impermeability and self-repairing ability of cracks damaged by load. The impermeability test blocks of Examples 1-12 were not permeable at 1.5MPa, and the 28d impermeability penetration height was lower than the 7d impermeability penetration height, and the compressive strength recovery rate under load reached 88-97%, which shows that the impermeability of the premixed dry self-repairing ordinary waterproof mortar of the present application is greater than 1.5MPa, and has excellent self-repairing ability of cracks damaged by load, can adapt to various complex environmental conditions, and is of great significance for improving the quality of building waterproofing projects under different environments.

[0061] According to the performance test results of Examples 1-5, Comparative Example 3 and Comparative Examples 5-6, it can be seen that the self-repairing masterbatch of water-crystalline material formed by super absorbent resin, nano-active silicon and fatty acid salt can significantly improve the impermeability and load damage recovery ability of waterproof mortar.

[0062] Fatty acid salts can be used as hydrophobic materials to balance the hydrophobicity and water absorption of waterproof mortar while maintaining various properties of waterproof mortar. On the one hand, they can prevent super absorbent resin from excessively absorbing water and maintain its expansion effect. On the other hand, they can prevent the reaction products of nano-active silicon from being corroded by water, maintain its stability, and enhance the self-repair ability of waterproof mortar against cracks damaged by load under high permeability conditions.

[0063] According to the performance test results of Examples 1-5, Examples 6-8 and Comparative Examples 1-2, it can be seen that nano-activated silicon, as an active ingredient in the self-healing material, can significantly promote the self-repair process of the waterproof mortar on the basis of the super absorbent resin absorbing water and swelling to block the cracks, further block the cracks, and improve the water tightness of the waterproof mortar.

[0064] In Comparative Example 1, silica fume is used to replace nano-active silicon, and in Comparative Example 2, nano-silicon dioxide is not surface-grafted and modified by a coupling agent. In both cases, the anti-seepage and self-repairing properties of the waterproof mortar are far inferior to those of the nano-active silicon group obtained by surface modification with a coupling agent. This is because nano-sized silicon dioxide has more excellent activity. After surface modification, on the one hand, nano-silicon dioxide has better dispersibility, overcomes the problem of self-agglomeration, and can be uniformly adsorbed on the surface of the polymer superabsorbent resin and distributed in the waterproof mortar. Further, one end of the coupling agent contains a group that can react with the hydroxyl group on the surface of nano-silicon dioxide, and the other end contains a group that can coordinate with calcium ions, which significantly enhances the reactivity of nano-active silicon and promotes the reaction between nano-active silicon and calcium ions, so that the crystals generated by the two in water have higher strength and stability, further enhancing the water tightness of the mortar, so that the waterproof mortar can maintain structural stability under high permeability, and has a more excellent self-repairing ability of cracks under load damage.

[0065] The various properties of the waterproof mortar in Example 7 are better than those of other groups, indicating that the waterproof mortar prepared by the self-repairing masterbatch formed by nano-active silicon modified by γ-(phosphate)propyltrimethoxysilane coupling agent has a more excellent self-repairing ability of load-damaged cracks under high permeability. This is because γ-(phosphate)propyltrimethoxysilane coupling agent has better hydrolysis stability than 3-aminopropyltriethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane and bis(2,3-epoxypropyl)phosphate, and can prevent structural damage caused by hydrolysis when exposed to water. It has higher reactivity, ensuring that the active groups on the surface of nano-silica can continue to react with calcium ions to generate insoluble calcium phosphate (Ca3(PO4)2) and other crystalline products, and form strong interface bonding to generate more dense and stable crystals, so that the waterproof mortar can be used in more complex, humid and acid-base conditions.

[0066] In addition, the Si-O-Si network formed after the hydrolysis of the siloxane group is hydrophobic and can form a hydrophobic layer on the surface and inside of the mortar to prevent water penetration. This hydrophobic layer effectively reduces the water absorption rate of the waterproof mortar and further improves the anti-seepage performance.

[0067] According to the performance test results of Examples 1-5 and Examples 9-10, it can be seen that the mixture of acrylamide-acrylonitrile-acrylic acid terpolymer and starch-acrylonitrile graft copolymer as a super absorbent resin has better performance effect. This is because the acrylamide-acrylonitrile-acrylic acid terpolymer provides good hydrophilicity and water absorption, while the starch-acrylonitrile graft copolymer provides additional hydrophilic groups, which enhances the water absorption capacity of the super absorbent resin. The three-dimensional network structure formed by the mixture can absorb and retain moisture more effectively, while enhancing the impermeability of the waterproof mortar in different acid and alkali environments.

[0068] According to the performance test results of Examples 1-5 and Examples 11-12, it can be seen that quartz sand as aggregate of waterproof mortar can enhance its compressive strength and wear resistance, and the use of quartz sand of different particle sizes can further optimize the particle grading of the mortar and improve its density and impermeability.

[0069] According to the performance test results of Examples 1-5 and Comparative Example 4, it can be seen that fatty acid salts can be used as hydrophobic materials. Compared with traditional hydrophobic agents, the use of fatty acid salts can play the role of hydrophobic agents without affecting the strength of the mortar, reduce the penetration of water, and cooperate with nano-active silicon and highly absorbent resin to effectively improve the impermeability of the waterproof mortar and the self-repair ability of cracks damaged by loads.

[0070] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A premixed dry self-repairing ordinary waterproof mortar, characterized in that: In terms of weight, the raw materials include 32-40 parts of Portland cement, 2-6 parts of silica fume, 2-6 parts of mineral powder, 55-60 parts of quartz sand, 0.05-0.1 parts of water reducer, 0.07-0.15 parts of HPMC, 0.1-0.2 parts of defoamer, 1-2 parts of heavy calcium carbonate and 6-10 parts of self-repairing masterbatch; The self-repairing masterbatch comprises highly water-absorbent resin, nano-active silicon and fatty acid salt.

2. The premixed dry self-repairing ordinary waterproof mortar according to claim 1 is characterized in that , in terms of weight, the raw materials of the self-healing masterbatch include 2.1-3.4 parts of super absorbent resin, 0.8-2.6 parts of nano-active silicon and 3.1-4 parts of fatty acid salt.

3. The premixed dry self-repairing ordinary waterproof mortar according to claim 2 is characterized in that The highly absorbent resin is a terpolymer of acrylamide-acrylonitrile-acrylic acid and a starch-acrylonitrile graft copolymer in a mass ratio of 1:(0.3-0.6).

4. The premixed dry self-repairing ordinary waterproof mortar according to claim 2 is characterized in that , the fatty acid salt is selected from any one or more combinations of sodium stearate, calcium stearate and potassium stearate.

5. The premixed dry self-repairing ordinary waterproof mortar according to claim 2 is characterized in that The method for preparing the nano-active silicon comprises the following steps: Add the coupling agent to ethanol and stir evenly to prepare a 5-10% coupling agent solution; Add nano-silica to the coupling agent solution, conduct ultrasonic dispersion reaction at 55-75°C for 5-6h, centrifuge, wash and then vacuum dry at 60-80°C to obtain; The coupling agent is selected from any one or more combinations of 3-aminopropyltriethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, γ-(phosphate)propyltrimethoxysilane and bis(2,3-epoxypropyl)phosphate.

6. The premixed dry self-repairing ordinary waterproof mortar according to claim 5 is characterized in that , the coupling agent is γ-(phosphate)propyltrimethoxysilane coupling agent.

7. The premixed dry self-repairing ordinary waterproof mortar according to claim 1 is characterized in that , the quartz sand includes 40-70 mesh quartz sand and 70-120 mesh quartz sand in a mass ratio of (7-8):(4-5).

8. The premixed dry self-repairing ordinary waterproof mortar according to claim 1 is characterized in that , the water reducer is a polycarboxylic acid water reducer.

9. The premixed dry self-repairing ordinary waterproof mortar according to claim 1 is characterized in that The viscosity of the HPMC is 50000 mPa·s and the density is 0.45 g / cm 3 .

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