Backwater face waterproof mortar and anti-seepage vapor-proof structure for underground building

Abstract

The invention provides downstream face waterproof mortar and an anti-seepage vapor-proof structure for an underground building, and belongs to the technical field of building materials. The downstream face waterproof mortar comprises the following raw materials in parts by weight: medium sand, ordinary Portland cement, aluminate cement, metakaolin and redispersible latex powder, wherein the total weight of the raw materials is 1000 parts; and potassium hydrogen phosphate and a water reducing agent.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and in particular relates to a back-water-side waterproof mortar and an anti-seepage vapor-isolating structure for underground buildings. Background Art

[0002] The development and utilization of underground space has become an inevitable demand for the development of modern cities and the direction of urban construction and development. Water leakage, damp walls, and mold caused by moisture and seepage seriously threaten the safety of underground buildings and have adverse effects on human health. Studies have shown that about 50% of households have mold problems to varying degrees, and damp walls are one of the main causes. It can be seen that the development of new anti-seepage and vapor-proof materials for underground space, effectively overcoming the problems of leakage and moisture, creating a healthy underground space environment, and achieving the goal of a beautiful human settlement are not only of far-reaching significance, but also have broad market prospects. Summary of the invention

[0003] In view of the above technical problems, the present invention provides a back-water waterproof mortar and an anti-seepage vapor barrier structure for underground buildings, in order to at least partially solve the above technical problems. The specific technical solutions provided by the present invention are as follows.

[0004] As a first aspect of the present invention, a back-water waterproof mortar is provided, the constituent raw materials of which include: medium sand, ordinary Portland cement, aluminate cement, kaolin, redispersible latex powder, with a total amount of 1000 parts; and potassium hydrogen phosphate and a water reducer.

[0005] As a second aspect of the present invention, there is provided an anti-seepage vapor barrier structure for underground buildings, comprising a waterproof layer formed on the surface of the base layer inside the underground building; wherein the waterproof layer is made of the above-mentioned back-water waterproof mortar.

[0006] In an embodiment of the present invention, a back-water waterproof mortar (hereinafter referred to as waterproof mortar) and an anti-seepage vapor barrier structure for underground buildings are provided. Potassium hydrogen phosphate and metakaolin are introduced into the waterproof mortar to regulate the hydration products of the mortar. In the early hydration process, potassium hydrogen phosphate can stimulate the hydration reaction between metakaolin and aluminate cement to generate calcium aluminum double hydroxide (Ca-Al-LDHs) and aluminum hydroxide (AH 3 ) gel. In the later stage of hydration, kaolin reacts with calcium hydroxide to produce hydrated calcite and hydrated calcium aluminosilicate (CASH) gel. These hydration products, namely calcium aluminum double hydroxide (Ca-Al-LDHs), aluminum hydroxide (AH 3) gel, hydrated calcium aluminum feldspar and hydrated calcium aluminosilicate (CASH) gel are interwoven to build a dense microstructure, which greatly reduces the porosity of the waterproof mortar after hardening, thereby significantly improving the waterproof mortar's impermeability and enabling it to effectively resist water penetration. Furthermore, layered double hydroxide (LDHs) crystals have a unique arrangement in the waterproof mortar. They exist in overlapping and parallel nanostructures, which greatly hinders the passage of water molecules. At the same time, the AH in the pores of the layered double hydroxide crystals 3 Gel and CASH gel have strong hydrogen bonding adsorption on water molecules, which further inhibits the diffusion of water molecules. Through these two effects, the anti-seepage and vapor barrier properties of waterproof mortar are significantly improved. DETAILED DESCRIPTION

[0007] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0008] At present, the waterproof layer of underground space in buildings mainly includes three key structural layers: external waterproofing, middle waterproofing and internal waterproofing. External waterproofing is located on the water-facing side, and mostly uses polymer membrane materials such as modified asphalt waterproofing membranes; middle waterproofing relies on the self-waterproofing layer of the concrete structure, which is mainly cast-in-place concrete mixed with waterproofing agents or penetrating crystallization agents; internal waterproofing is located on the back of the water, and commonly uses waterproofing materials such as polymer waterproof coatings and polymer waterproof mortars.

[0009] Among the waterproof materials for the back water surface, polymer waterproof coating is a flexible material with good extensibility, not easy to crack, low water vapor permeability, and good vapor barrier and moisture-proof effect. However, facing the high osmotic water pressure in the underground space, it is easy to deform and bulge over a large area. Long-term water storage in the cavity at the bulging place will cause the polymer coating to swell and soften and then fail. Therefore, polymer waterproof coating is not suitable for direct use in the high water pressure environment of the back water surface, and its long-term reliability is poor. Polymer waterproof mortar is a polymer-modified inorganic waterproof material. When used on the back water surface, the construction thickness is greater than 15mm and it can have a high anti-seepage ability (1.0Mpa), but the thick layer construction is prone to cracking and there is a risk of leakage; when the thin layer is constructed (≤8mm), the anti-seepage ability is greatly reduced, and the water vapor permeability is high, and it does not have the ability to isolate and prevent vapor and moisture.

[0010] At present, there is a kind of impermeable mortar made of water-absorbent resin. According to the JGJ / T 70-2009 standard test, the impermeability pressure of 30mm thick mortar can reach 2.0MPa, but the shrinkage of water-absorbent resin will reduce the density of mortar. The impermeability of thin layer mortar (≤8mm) is significantly lower than that of thick layer, and it also has no effect of steam and moisture barrier. There is also an impermeable mortar made of glass powder, glass flakes, sulfate and strong alkali. The water seepage height of 30mm thick mortar under 1.2MPa pressure is 12.1mm, which shows that this type of mortar does not have the impermeability of thin layer (≤8mm) and also does not have the effect of steam and moisture barrier. In addition, there is a back-water mortar made of alum stone powder modified polypropylene fiber. According to JC / T 984-2011, the anti-seepage of the mortar with a thickness of 30mm reaches 1.5MPa. After the alum stone powder is added to cement, it can be hydrated to form expanded crystals of calcium aluminate, which can improve the compactness of the mortar. The polypropylene fiber has a significant improvement on the crack resistance of the mortar. However, for thin-layer mortar (≤8mm), the weak interface between the organic fiber and the inorganic hydration product of cement will become a water seepage channel, resulting in reduced anti-seepage. Moreover, although the expanded calcium aluminate can improve the compactness against water penetration, it has no effect on water vapor penetration and does not have the ability to isolate and prevent steam and moisture.

[0011] In summary, the back-water waterproof mortar prepared by the prior art can only improve the impermeability and crack resistance of the thick layer mortar. However, in practical applications, the thick layer mortar not only occupies indoor space, but also takes time and effort to construct, and does not have the effect of steam and moisture insulation. When blocking the infiltration of underground open water, it is impossible to prevent the invasion of water vapor, resulting in high humidity in the underground space, and the walls and furniture are prone to mold, which seriously endangers human health. Therefore, it is urgent to develop an impermeable and steam-insulating thin layer back-water waterproof mortar and its preparation and application method.

[0012] Based on this, the present invention provides a back-water surface waterproof mortar and an anti-seepage vapor barrier structure for underground buildings. The components of the back-water surface waterproof mortar include aluminate cement, metakaolin and potassium hydrogen phosphate, so that the back-water surface waterproof mortar provided by the present invention has a significantly improved anti-seepage ability compared with the prior art when the construction thickness is 3mm, and has a lower water vapor permeability, which can solve the problem of leakage and moisture in underground space.

[0013] As a first aspect of the present invention, a back-water waterproof mortar is provided, the constituent raw materials of which include: medium sand, ordinary Portland cement, aluminate cement, kaolin, redispersible latex powder, with a total amount of 1000 parts; and potassium hydrogen phosphate and a water reducer.

[0014] In the embodiment of the present invention, potassium hydrogen phosphate and metakaolin are introduced into the waterproof mortar to regulate the hydration products of the mortar. In the early hydration process, potassium hydrogen phosphate can stimulate the hydration reaction between metakaolin and aluminate cement to generate calcium aluminum double hydroxide (Ca-Al-LDHs) and aluminum hydroxide (AH 3 ) gel. In the later stage of hydration, kaolin reacts with calcium hydroxide to produce hydrated calcite and hydrated calcium aluminosilicate (CASH) gel. These hydration products, namely calcium aluminum double hydroxide (Ca-Al-LDHs), aluminum hydroxide (AH 3 ) gel, hydrated calcium aluminum feldspar and hydrated calcium aluminosilicate (CASH) gel are interwoven to build a dense microstructure, which greatly reduces the porosity of the waterproof mortar after hardening, thereby significantly improving the waterproof mortar's impermeability and enabling it to effectively resist water penetration. Furthermore, layered double hydroxide (LDHs) crystals have a unique arrangement in the waterproof mortar. They exist in overlapping and parallel nanostructures, which greatly hinders the passage of water molecules. At the same time, the AH in the pores of the layered double hydroxide crystals 3 Gel and CASH gel have strong hydrogen bonding adsorption on water molecules, which further inhibits the diffusion of water molecules. Through these two effects, the anti-seepage and vapor barrier properties of waterproof mortar are significantly improved.

[0015] According to an embodiment of the present invention, medium sand includes 400-600 parts, ordinary Portland cement includes 309-450 parts, aluminate cement includes 1-30 parts, metakaolin includes 30-60 parts, redispersible latex powder includes 30-60 parts, potassium hydrogen phosphate includes 0.9-3 parts, and water reducer includes 3-6 parts. Medium sand includes at least one of natural sand and artificial sand. Ordinary Portland cement includes at least one of gray cement and white cement. Potassium hydrogen phosphate includes at least one of dipotassium hydrogen phosphate and potassium dihydrogen phosphate. Al in metakaolin 2 O 3 The content is not less than 35%, and the activity index is not less than 100%. In addition, the raw materials of waterproof mortar also include: 0.5-2 parts of cellulose ether, 0.4-0.8 parts of water repellent, and 0.2-0.4 parts of defoaming agent.

[0016] In the embodiment of the present invention, the medium sand is used as aggregate to build a stable structural framework for the waterproof mortar, effectively enhancing the overall strength of the waterproof mortar. Ordinary Portland cement can improve the setting speed and strength of the waterproof mortar. The compact structure formed by rapid setting reduces the pores that can be penetrated by water vapor and improves the anti-seepage ability. Under the stimulation of potassium hydrogen phosphate, kaolin and aluminate cement generate special products (i.e. calcium aluminum double hydroxide (Ca-Al-LDHs) and aluminum hydroxide (AH 3) gel, which reduces the porosity of the waterproof mortar, significantly improves the anti-seepage performance, effectively blocks the passage of water vapor molecules, and achieves a good vapor barrier effect. Redispersible latex powder can enhance the flexibility and adhesion of the waterproof mortar, make the waterproof mortar fit closely with the base layer, reduce the generation of gaps, and prevent water vapor from invading from the gaps. Water reducer can reduce the amount of water used in the construction of waterproof mortar, reduce the pores left by the evaporation of excess water, and improve the density of the waterproof mortar. In addition, cellulose ether, water repellent and defoamer are added to the waterproof mortar. Cellulose ether can improve the water retention of the waterproof mortar, avoid the loose structure caused by excessive water loss, and ensure the stability of the waterproof mortar structure. Water repellent can prevent water from invading from the root, making it difficult for water vapor to enter the waterproof mortar. Defoamer can eliminate bubbles generated during the mixing process, reduce pores, improve the density of the waterproof mortar, and enhance the anti-seepage vapor barrier effect. Through the synergistic cooperation of various components, it can effectively solve the problems of moisture and leakage in the building base, and create a dry and comfortable environment for the building space.

[0017] Specifically, the redispersible latex powder can be selected from acrylate redispersible latex powder, vinyl acetate redispersible latex powder, etc.; the water reducer can be selected from lignin sulfonate water reducer, naphthalene water reducer, polycarboxylic acid water reducer, etc.; the cellulose ether can be selected from methyl cellulose ether, hydroxypropyl methyl cellulose ether, etc.; the hydrophobic agent can be selected from silicone water repellent, fatty acid water repellent, etc.; the defoamer can be selected from silicone defoamer, polyether defoamer, mineral oil defoamer, etc. It should be understood that in addition to the various types of redispersible latex powder, water reducer, cellulose ether, hydrophobic agent and defoamer mentioned above, in practical applications, other commonly used similar materials are also applicable, and the present invention is not limited thereto.

[0018] As a second aspect of the present invention, there is provided an anti-seepage vapor barrier structure for underground buildings, comprising a waterproof layer formed on the surface of the base layer inside the underground building; wherein the waterproof layer is made of the above-mentioned back-water waterproof mortar.

[0019] In the embodiment of the present invention, multiple components in the waterproof mortar work synergistically to form a dense microstructure. 3 The gel, interwoven with the later hydrated gross aluminum feldspar and CASH gel, greatly reduced the porosity of the waterproof mortar. This enables the waterproof layer to effectively block the high-pressure water penetration that may occur in underground buildings, prevent structural damage caused by leakage, internal facilities from getting damp, and other problems, and ensure the stability and safety of underground building structures. The unique overlapping and parallel nano-arranged structure of layered double hydroxide crystals in the waterproof mortar hinders the passage of water vapor molecules. At the same time, the AH in the pores 3The strong hydrogen bond adsorption of gel and CASH gel on water molecules further inhibits the diffusion of water vapor, so that the interior of underground buildings can effectively resist water vapor invasion, maintain a relatively dry environment, avoid wall mold and item deterioration caused by moisture, and maintain a healthy indoor environment. The waterproof mortar formula provided by the present invention is reasonably designed, the raw materials are common and easy to obtain, and the stable chemical reactions and physical structures between the components give the waterproof layer good durability. In the long-term complex underground environment, under the influence of factors such as temperature changes, humidity fluctuations, and soil pressure, the anti-seepage and vapor isolation performance of the waterproof layer can still remain stable, reducing the frequency of later maintenance and renovation, and providing long-lasting and reliable protection for underground buildings.

[0020] According to an embodiment of the present invention, the thickness of the waterproof layer does not exceed 3 mm. The thinner waterproof layer is easier to apply, the construction difficulty is reduced, the construction efficiency can be improved, and the rework caused by construction errors can be reduced, and the risk of water seepage caused by cracking can be reduced. The base layer includes a concrete base layer or a cement mortar base layer to meet the needs of different construction projects.

[0021] According to an embodiment of the present invention, the waterproof layer is prepared by adding water to the waterproof mortar and stirring it evenly, and then coating it on the surface of the base layer. The waterproof mortar includes 1000 parts, and the water includes 180-200 parts. The manufacturing process of the anti-seepage vapor barrier structure for underground buildings provided by the present invention is relatively simple, which is convenient for large-scale preparation and construction at the construction site. Moreover, compared with some traditional anti-seepage vapor barrier materials and construction methods, it does not require complicated construction equipment and processes, can effectively shorten the construction period, reduce construction costs, and improve the efficiency and economic benefits of underground building construction.

[0022] Specifically, in some embodiments of the present invention, the above-mentioned construction process for anti-seepage and vapor-proof of underground buildings includes: weighing the raw materials of each component according to the measurement, mixing them evenly to obtain waterproof mortar for the back water surface; adding 180-200 parts of water to 1000 parts of waterproof mortar, mixing and stirring for 3 minutes, the stirring rate is 400-800r / min, standing for 2 minutes and stirring again for 1 minute to complete the mortar mixing; on the cleaned and solid concrete or cement mortar base, scrape the waterproof mortar twice, the thickness of a single scraping is not less than 1.5mm, and the thickness of two scrapings reaches 3mm, and the construction is completed after curing.

[0023] The present invention is further described below by examples and related test experiments. In the detailed description below, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present invention. However, it is obvious that one or more embodiments may also be implemented without these specific details. And, in the absence of conflict, the details in the following embodiments may be combined into other feasible embodiments at will. All instruments, consumables and reagents in the following examples, if not otherwise specified, may be obtained from commercial sources.

[0024] The raw material types and manufacturers used in the examples and comparative examples of the present invention are as follows.

[0025] Natural sand was purchased from Hebei Feixi New Material Technology Co., Ltd., river sand, mesh size 40-140 mesh;

[0026] Artificial sand was purchased from Liaoning Jinlun Mineral Products Co., Ltd., dolomite machine-made sand, mesh size 40-140 mesh;

[0027] Grey cement was purchased from Anhui Conch Cement Co., Ltd., model PO 42.5;

[0028] White cement was purchased from Aalborg Portland (Anqing) Co., Ltd., model PW 52.5;

[0029] Aluminate cement was purchased from Qenos (China) Aluminate Technology Co., Ltd., model CA70;

[0030] Kaolin was purchased from Inner Mongolia Chaopai Building Materials Co., Ltd., model K1100, 800 mesh, Al 2 O 3 Content 42%, activity index 108%;

[0031] The redispersible latex powder was purchased from Wacker Chemicals (China) Co., Ltd., model 5010N;

[0032] Potassium hydrogen phosphate was purchased from Beijing Kangpu Huiwei Technology Co., Ltd., industrial grade;

[0033] Cellulose ether was purchased from Dow Chemical Company, USA, hydroxyethyl methyl cellulose, model WALOCEL TM MKW40000PP10;

[0034] The water reducer was purchased from Sika (China) Co., Ltd., model 530P;

[0035] The water repellent was purchased from Akzo Nobel Paints (China) Co., Ltd., model SEAL80;

[0036] The defoamer was purchased from Germany's Mingling Chemical, a silicone powder defoamer, model AGITANR P803.

[0037] Example 1

[0038] The raw materials and proportions of the back water surface waterproof mortar provided in this embodiment 1 are detailed in Table 1.

[0039] The construction method of the back water surface waterproof mortar specifically comprises the following steps.

[0040] (1) Weigh the raw materials of each component according to the measurement, mix them evenly to obtain the back-water surface waterproof mortar.

[0041] (2) Add 200 parts of water to 1000 parts of waterproof mortar, mix and stir for 3 minutes at a stirring rate of 400 r / min. After standing for 2 minutes, stir again for 1 minute to complete the mortar mixing.

[0042] (3) Apply waterproof mortar twice on the cleaned and solid concrete base. The thickness of a single coat should not be less than 1.5 mm, and the thickness of two coats should reach 3 mm. After curing, the construction is completed.

[0043] The anti-seepage pressure and bonding strength of the mortar on the back water surface were tested according to JC / T 984-2011 “Polymer cement waterproof mortar”; the water vapor permeability was tested according to GB / T 17146-2015 “Test method for water vapor permeability of building materials and their products”. The test results are shown in Table 1.

[0044] Example 2

[0045] The raw materials and proportions of the back surface waterproof mortar provided in this embodiment 2 are shown in Table 1. The construction method and the detection method are the same as those in embodiment 1, and the detection results are shown in Table 1.

[0046] Example 3

[0047] The raw materials and proportions of the back surface waterproof mortar provided in this embodiment 3 are shown in Table 1. The construction method and the detection method are the same as those in embodiment 1, and the detection results are shown in Table 1.

[0048] Example 4

[0049] The raw materials and proportions of the back-water surface waterproof mortar provided in this embodiment 4 are shown in Table 1. The construction method and the detection method are the same as those in embodiment 1, and the detection results are shown in Table 1.

[0050] Example 5

[0051] The raw materials and proportions of the back water surface waterproof mortar provided in this Example 5 are detailed in Table 1.

[0052] The construction method of the back water surface waterproof mortar specifically comprises the following steps.

[0053] (1) Weigh the raw materials of each component according to the measurement, mix them evenly to obtain the back-water surface waterproof mortar.

[0054] (2) Add 180 parts of water to 1000 parts of waterproof mortar, mix and stir for 3 minutes at a stirring rate of 800 r / min. After standing for 2 minutes, stir again for 1 minute to complete the mortar mixing.

[0055] (3) Apply waterproof mortar twice on the cleaned and solid concrete base. The thickness of a single coat should not be less than 1.5 mm, and the thickness of two coats should reach 3 mm. After curing, the construction is completed.

[0056] The detection method is the same as in Example 1, and the detection results are shown in Table 1.

[0057] Comparative Example 1

[0058] The raw materials and proportions of the back-water surface waterproof mortar provided in this comparative example 1 are shown in Table 1. The construction method and the detection method are the same as those in Example 1, and the detection results are shown in Table 1.

[0059] Comparative Example 2

[0060] The raw materials and proportions of the back-water surface waterproof mortar provided in this comparative example 1 are shown in Table 1. The construction method and the detection method are the same as those in Example 1, and the detection results are shown in Table 1.

[0061] Comparative Example 3

[0062] This comparative example 3 is a commercially available JS-II type polymer cement waterproof coating. The detection method is the same as that of Example 1. The detection results are shown in Table 1.

[0063] Table 1 Waterproof mortar mix ratios and test results of Examples 1-5 and Comparative Examples 1-3

[0064]

[0065] As shown in Table 1, the above embodiments and comparative examples and test data show that the back-water surface waterproof mortar provided by the present invention can regulate the hydration products of the mortar, namely calcium aluminum double hydroxide (Ca-Al-LDHs), aluminum hydroxide (AH 3 ) gel, hydrated calcium aluminum feldspar and hydrated calcium aluminosilicate (CASH) gel to achieve the anti-seepage and vapor isolation effect. Among them, calcium aluminum double hydroxide forms a dense and specially arranged nanostructure in the waterproof mortar layer, and AH 3 The adsorption of water molecules by gel and CASH gel achieves high impermeability and high vapor isolation of 3mm thin layer waterproof mortar on the back of the water surface. It can withstand the water pressure at a depth of 200m underground, and the minimum water vapor permeability can reach 7g / (m 2 ·24h), comparable to the moisture-proof effect of flexible polymer waterproof coating. The specific comparative analysis is as follows.

[0066] Examples 1 to 3 are solutions with different amounts of potassium hydrogen phosphate and metakaolin. It can be seen that with the increase in the amount of potassium hydrogen phosphate and metakaolin, the anti-seepage pressure that the mortar on the back of the water surface can withstand gradually increases, and the water vapor permeability gradually decreases. This is because the metakaolin originally generates needle-shaped hydrated calcium aluminum feldspar and CASH gel in the alkaline environment of cement hydration. With the increase in the amount of potassium hydrogen phosphate and metakaolin, the volcanic ash reaction of the metakaolin is partially inhibited under the stimulation of potassium hydrogen phosphate. In the early hydration process, the Al(OH) released after the metakaolin alkali dissolution 4 − Produce calcium aluminum double hydroxide and AH 3 Gel, in the middle and late hydration process, continues to generate hydrated gross aluminum feldspar and CASH gel. At the same time, the above reaction consumes the large-sized thin plate-like Ca(OH) generated by the cement itself, which will cause the mortar to loosen. 2 , new hydration products (i.e. calcium aluminum double hydroxide, AH 3 The gel) is interwoven with calcite and CASH gel to form a dense microstructure, which significantly reduces the porosity of the hardened mortar, making it difficult for high-pressure water to pass through the mortar structure layer, thereby improving the anti-seepage ability of the thin-layer waterproof mortar; at the same time, the overlapping and parallel special arrangement of layered double hydroxide crystals in the waterproof mortar hinders the passage of water molecules, and the AH in the pores 3 Gel and CASH gel have strong hydrogen bond adsorption on water molecules, which further hinders the diffusion of water molecules, thereby significantly reducing water vapor permeability and achieving high vapor and moisture barrier effects of thin-layer waterproof mortar.

[0067] Compared with Examples 1 to 3, Example 4 significantly increases the amount of aluminate cement used. Since aluminate hydration speed is relatively fast, and under the action of potassium dihydrogen phosphate, aluminate cement hydrates to generate calcium aluminate hydrate (C 2 AH 8 ) reaction is inhibited, making the Al(OH) 4 − The concentration increases rapidly, so the early Ca-Al-LDHs and AH 3 The amount of gel generated is further increased, and the amount of kaolin used is adjusted, which can further improve the density of the waterproof mortar structure, achieve an anti-seepage pressure of 1.7MPa, and reduce the water vapor permeability to 12g / (m 2 ·24h).

[0068] Example 5 is a scheme for replacing gray cement and machine-made sand, and increasing the dosage of metakaolin, aluminate cement, rubber powder, potassium hydrogen phosphate and other additives. The test results show that the anti-seepage pressure of the mortar on the back water surface reaches 2.0MPa, and the water vapor permeability is as low as 7g / (m 2·24h), the bonding strength reached 3.2MPa, which shows that by adjusting the dosage of key components, a high-performance anti-seepage and vapor-isolating thin-layer back-water waterproof mortar can be prepared even with low-cost gray cement and machine-made sand.

[0069] Comparative Example 1 is a solution without adding potassium hydrogen phosphate. Compared with Example 1, due to the pozzolanic reaction of metakaolin in the alkaline environment of cement hydration, a large amount of Ca(OH) 2 , and the generated needle-rod-shaped hydrated calcium aluminum feldspar and CASH gel also have a good effect on improving the density of the mortar structure, so the anti-seepage pressure of the mortar on the back water surface has not been significantly reduced. However, due to the lack of potassium hydrogen phosphate, the metakaolin cannot be stimulated to generate layered double hydroxides, and there is no overlapping and parallel special arrangement of nanostructures, so the water vapor permeability is significantly increased. The anti-seepage effect of this solution is acceptable, but the vapor and moisture barrier performance is poor.

[0070] Comparative Example 2 is a solution without adding kaolin. Compared with Example 1, due to the lack of kaolin, the Al(OH) 4 − Due to the lack of key nanostructures and the reduction of gel products, the water vapor permeability is significantly increased, and the anti-seepage and vapor barrier properties of this scheme are poor.

[0071] Comparative Example 3 is a conventional commercially available JS-II flexible polymer cement waterproof coating. The test results show that its anti-seepage ability and bonding strength are relatively low. Therefore, when the material is constructed in a back-water environment, it is difficult to resist high-pressure water erosion and does not have the back-water waterproof ability. However, due to the high polymer content of the material, the water vapor barrier effect is better after film formation, so the conventional construction plan will be adopted, first constructing ordinary back-water anti-seepage mortar to provide anti-seepage effect, and then constructing JS waterproof coating to achieve vapor isolation effect.

[0072] In summary, the present invention aims at the problems that the existing thin-layer back-water surface waterproof mortar has poor impermeability and poor steam and moisture-proof effect, and provides an impermeable and steam-proof thin-layer back-water surface waterproof mortar. With a construction thickness of 3mm, the maximum impermeability pressure of the back-water surface mortar can reach 2.0Mpa, that is, it can withstand the water pressure at a depth of 200 meters, and its performance is significantly better than the polymer cement waterproof mortar in the prior art; at the same time, the 3mm waterproof mortar can reach a minimum of 7g / (m 2·24h) is better than the conventional JS-II polymer cement waterproof coating. Therefore, there is no need to adopt a composite solution. A single material can achieve anti-seepage and waterproofing of the back water surface and vapor and moisture isolation, simplifying the construction process, shortening the construction period, saving material and labor costs, solving the problems of leakage and moisture in the underground space, creating a healthy environment in the underground space, and realizing a beautiful human settlement.

[0073] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A waterproof mortar for back water surface, characterized in that: The raw materials of the waterproof mortar include: medium sand, ordinary Portland cement, aluminate cement, metakaolin, and redispersible latex powder, with a total amount of 1000 parts; and Potassium hydrogen phosphate and water reducing agent.

2. The waterproof mortar according to claim 1, characterized in that: The medium sand comprises 400-600 parts, the ordinary Portland cement comprises 309-450 parts, the aluminate cement comprises 1-30 parts, the metakaolin comprises 30-60 parts, the redispersible latex powder comprises 30-60 parts, the potassium hydrogen phosphate comprises 0.9-3 parts, and the water reducing agent comprises 3-6 parts.

3. The waterproof mortar according to claim 2, characterized in that: The medium sand includes at least one of natural sand and artificial sand; The ordinary Portland cement includes at least one of gray cement and white cement.

4. The waterproof mortar according to claim 2, characterized in that: The potassium hydrogen phosphate includes at least one of dipotassium hydrogen phosphate and potassium dihydrogen phosphate.

5. The waterproof mortar according to claim 2, characterized in that: The Al2O3 content in the metakaolin is not less than 35%, and the activity index of the metakaolin is not less than 100%.

6. The waterproof mortar according to claim 2, characterized in that: The raw materials of the waterproof mortar also include: 0.5-2 parts of cellulose ether, 0.4-0.8 parts of water repellent, and 0.2-0.4 parts of defoaming agent.

7. An anti-seepage vapor barrier structure for underground buildings, characterized in that: The structure includes a waterproof layer formed on the surface of the base layer inside the underground building; Wherein, the waterproof layer is made of the waterproof mortar described in any one of claims 1 to 6.

8. The structure according to claim 1, characterized in that The thickness of the waterproof layer shall not exceed 3 mm; The base layer includes a concrete base layer or a cement mortar base layer.

9. The structure according to claim 7, characterized in that The waterproof layer is prepared by adding water into the waterproof mortar and stirring the mortar evenly, and then coating the mortar on the surface of the base layer.

10. The structure according to claim 9, characterized in that In parts by weight, the waterproof mortar comprises 1000 parts, and the water comprises 180-200 parts.

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