Improved reactive sand and method for making same

Abstract

The application discloses improved reactive sand and a preparation method thereof, which comprises the following raw materials: 20-30 parts of ordinary Portland cement or white cement, 5-10 parts of silica fume, 0.1-0.3 parts of triethanolamine, 0.5-1.0 parts of nano-silicon dioxide, 40-60 parts of quartz powder, 0.3-0.6 parts of silane coupling agent, 0.2-0.3 parts of carboxylic acid water reducing agent and 20-30 parts of water. 2+ 3+ The application has the beneficial effect that the improved reactive sand contains a large amount of active components, such as nano-silicon dioxide, silica fume and the like, which can easily react with the multivalent ions such as Ca 2+ 3+ , Al 3+ and the like in the cement hydration products to generate crystalline materials. When the concrete is poured, the active components in the reactive sand migrate and diffuse into the capillary pores of the concrete by means of the siphon effect of water, and part of the active components react; when the concrete is dried, the reactive sand is in a dormant state, and is activated when water is encountered to generate crystals and repair the cracks in the concrete.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of waterproof materials, and particularly relates to a modified reaction sand and a preparation method thereof. BACKGROUND

[0002] The isolation sand for the polymer self-adhesive film waterproof roll material is generally divided into four types: quartz sand, cement sand, reaction sand and mullite sand. The reaction sand is more commonly used in production due to its high performance-price ratio. The reaction sand is a sintered sand and has a core-shell structure. The core is generally formed by mixing gypsum powder, calcite powder and the like, and then sintering at high temperature to form a block, and then grinding the block into reaction sand with a required particle size. The shell structure is composed of acrylic emulsion, pigments and the like, and is coated on the outside of the core to reduce dust and facilitate bonding. As can be seen, all the components of the reaction sand in the prior art are inert materials, which only play a role of isolation material for the waterproof roll material, are scattered on the adhesive layer to avoid sticking feet and facilitate operation. In addition, the compressive strength of the existing reaction sand is generally 3-5 MPa (a multi-hole structure is formed by sintering gypsum at high temperature), which is relatively low. In production, the reaction sand is scattered on the self-adhesive film, and in the process of double-roll extrusion in the next process, the reaction sand is easily crushed into powder and adheres to the surface of the self-adhesive layer, resulting in a decrease in sand sticking rate, a decrease in the peeling and bonding performance of the roll material with post-poured concrete in use, and in serious cases, the roll material and the concrete are locally separated and appear to be hollow, and a large amount of water is accumulated in the hollow, which causes the roll material to become a helper of water storage and leakage. SUMMARY

[0003] The application aims to provide a modified reaction sand with the functions of repairing concrete cracks and preventing water leakage and a preparation method thereof.

[0004] To achieve the above-mentioned purpose of the application, the following technical scheme is adopted in the application.

[0005] The modified reaction sand comprises the following raw materials in parts by weight: ordinary Portland cement (P.O 42.5 or P.O 52.5) or white cement (P.W 42.5 or P.W 52.5) 20-30 parts, silica fume powder 5-10 parts, triethanolamine 0.1-0.3 parts, nano-silicon dioxide 0.5-1.0 parts, quartz powder 40-60 parts, silane coupling agent 0.3-0.6 parts, carboxylic acid water reducing agent 0.2-0.3 parts, and water 20-30 parts.

[0006] The modified reactive sand described in the present application uses ordinary Portland cement or white cement as the cementitious material, and the amount of cement is controlled to be 20%-30%. The addition of cement can increase the strength of the reactive sand, so that the compressive strength of the reactive sand can reach 15-25 MPa, which is much greater than the 3-5 MPa of the reactive sand itself. Secondly, the proportion of cement cannot be too large, otherwise too much active material such as nano-silicon dioxide and silica powder will be consumed during the slurry preparation and solidification process, resulting in less active material penetrating into the concrete after the modified reactive sand is used to prepare the coiled material construction pouring concrete. The modified reactive sand manufacturing process, especially the slurry stirring speed and low temperature requirements (to prevent the loss of active ingredients under high temperature stirring), and the slurry solidification water removal must be strictly controlled.

[0007] Silica powder is mainly composed of micron-sized silicon dioxide, which is active after high-temperature firing and can react with cement. It is a commonly used reinforcing material for concrete.

[0008] Triethanolamine is a commonly used early strength material for concrete. After the concrete is poured, triethanolamine migrates from the reactive sand to the concrete, has an early strength and strengthening effect on the interface concrete of the coiled material, and increases the bonding strength between the concrete and the coiled material.

[0009] Nanosilicon dioxide has a particle size of 0.001 microns, and the particle surface contains a large number of hydroxyl groups (-OH). Through the siphon effect of water, it penetrates into the capillary pores of the concrete, easily reacts with the cement hydration products Ca 2+ , Al 3+ and other multivalent ions to generate crystalline materials, and repairs the capillary pores and cracks of the concrete.

[0010] Quartz powder is used as a filler, and the fineness of quartz powder is limited to 150-200 mesh, which does not use ultra-fine powder. This is beneficial to increase the porosity of the reactive sand and facilitate the migration of active ingredients to the poured concrete.

[0011] Carboxylic acid water reducing agent can greatly reduce the water consumption of slurry stirring, which is beneficial to the strength of the reactive sand itself. Secondly, after the concrete is poured, it diffuses to the interface concrete, enhances the fluidity and compactness of the interface concrete, and thus strengthens the bonding strength between the concrete and the coiled material.

[0012] The above-mentioned modified reactive sand, as a preferred embodiment, comprises the following raw materials in parts by weight: ordinary Portland cement (P.O 42.5 or P.O 52.5) or white cement (P.W 42.5 or P.W 52.5) 22-28 parts, silica powder 6-8 parts, triethanolamine 0.1-0.2 parts, nanosilicon dioxide 0.6-0.8 parts, quartz powder 45-55 parts, silane coupling agent 0.4-0.5 parts, carboxylic acid water reducing agent 0.2-0.3 parts, and water 22-28 parts.

[0013] As a preferred embodiment of the improved reactive sand, the fineness of the quartz powder is 150-200 mesh.

[0014] In a second aspect of the present application, a method for preparing the improved reactive sand is provided, comprising the following steps:

[0015] (1) uniformly mixing cement, silica powder and quartz powder, spraying the atomized silane coupling agent on the mixture, continuously mixing and uniformly mixing, and allowing the silane coupling agent to react with the mixture by standing;

[0016] (2) adding triethanolamine, nano-silicon dioxide and carboxylic acid water reducing agent to the product obtained in step (1), uniformly stirring, and adding water to prepare a viscous slurry;

[0017] (3) curing the slurry, crushing and sieving to obtain the modified reactive sand.

[0018] As a preferred embodiment of the method for preparing the improved reactive sand, in step (1), the speed of mixing and stirring is 40-120 r / min, and the temperature of mixing and stirring is 15-30℃.

[0019] The surface of the cement, silica powder and quartz powder is treated by the silane coupling agent, thereby enhancing the affinity of the reactive sand to the organic hot melt adhesive and the post-cast inorganic building concrete, and increasing the bonding force.

[0020] As a preferred embodiment of the method for preparing the improved reactive sand, in step (1), the standing time is 20-28 h.

[0021] As a preferred embodiment of the method for preparing the improved reactive sand, in step (1), the temperature of the reaction of the silane coupling agent with the mixture is 15-30℃.

[0022] As a preferred embodiment of the method for preparing the improved reactive sand, in step (2), the speed of stirring is 80-160 r / min, and the stirring temperature is 4-8℃.

[0023] Preferably, in step (3), the viscous slurry is first placed in a closed device, and the excess water in the slurry is removed by negative pressure water absorption treatment until the pressure in the closed device is 20-30 KPa, and then the slurry is cured at room temperature for 6-8 days, and the fineness of the modified reactive sand obtained by crushing is 30-50 mesh.

[0024] In a third aspect of the present application, the improved reactive sand is applied in a waterproof roll material.

[0025] The improved reactive sand contains a large amount of active substances, such as nano-silicon dioxide and silica powder, which can easily react with the cement hydration product Ca 2+ , Al3+ The active components in the reaction sand react with the multivalent ions to form crystalline materials. After the concrete is poured, the active components in the reaction sand migrate, diffuse and react in the capillary pores of the concrete with the aid of the siphoning action of water. When the concrete dries, the reaction sand is in a dormant state and is activated by water to react to form crystals, repair cracks in the concrete and improve the impermeability and waterproof performance of the concrete. DETAILED DESCRIPTION

[0026] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described in detail below. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0027] Embodiment 1

[0028] An improved reaction sand comprises the following raw materials in parts by weight: Portland cement (P.O 42.5)

[0029] 24.80 parts of P.O 42.5 Portland cement, 6.40 parts of silica fume, 45.40 parts of quartz powder with a fineness of 150-200 mesh, 0.45 parts of silane coupling agent, 0.24 parts of carboxylic acid water reducing agent, and 22.17 parts of water.

[0030] The preparation method of the improved reaction sand described in Embodiment 1 comprises the following steps:

[0031] (1) 24.80 parts of P.O 42.5 Portland cement, 6.40 parts of silica fume and 45.40 parts of quartz powder are uniformly mixed and stirred at a stirring speed of 60 r / min and a temperature of 20℃, 0.45 parts of atomized silane coupling agent is sprayed on the mixture, and the mixture is continuously stirred and mixed until the silane coupling agent is reacted with the mixture for 20 h;

[0032] (2) 0.12 parts of triethanolamine, 0.74 parts of nano-silicon dioxide and 0.24 parts of carboxylic acid water reducing agent are added to the product obtained in step (1), and 22.17 parts of water is stirred at a stirring speed of 120 r / min and a temperature of 6℃ for 1 h to prepare a viscous slurry;

[0033] (3) The viscous slurry in step (2) is first placed in a sealed device, and the excess water in the slurry is removed by negative pressure water absorption treatment until the pressure in the sealed device is 25 KPa, and then the slurry is cured at room temperature for 7 days, and the modified reaction sand with a fineness of 30-50 mesh is obtained by crushing and sieving.

[0034] Embodiment 2

[0035] An improved reactive sand, comprising the following raw materials by weight, Portland cement (P.O 52.5) 22.60 parts, silica fume 6.60 parts, triethanolamine 0.19 parts, nano-silica 0.72 parts, quartz powder with fineness of 150-200 mesh 46.40 parts, silane coupling agent 0.46 parts, carboxylic acid water reducing agent 0.25 parts, water 22.78 parts.

[0036] 22.60 parts of Portland cement, 6.60 parts of silica fume, 46.40 parts of quartz powder with fineness of 150-200 mesh, 0.46 parts of silane coupling agent, 0.25 parts of carboxylic acid water reducing agent, and 22.78 parts of water.

[0037] The preparation method of the improved reactive sand described in Example 2, comprising the following steps:

[0038] (1) 22.60 parts of Portland cement, 6.60 parts of silica fume, and 46.40 parts of quartz powder are uniformly mixed and stirred at a stirring speed of 80 r / min and a temperature of 25°C, 0.46 parts of atomized silane coupling agent is sprayed on the mixture, and the mixture is continuously stirred and mixed uniformly, and the silane coupling agent is allowed to react with the mixture for 25 hours;

[0039] (2) 0.19 parts of triethanolamine, 0.72 parts of nano-silica, 0.25 parts of carboxylic acid water reducing agent, and 22.78 parts of water are added to the product obtained in step (1), stirred at a stirring speed of 120 r / min and a temperature of 8°C for 1 hour to prepare a viscous slurry;

[0040] (3) The viscous slurry in step (2) is first placed in a sealed device, and the excess water in the slurry is removed by negative pressure water absorption treatment until the pressure in the sealed device is 22 KPa, and then the slurry is cured at room temperature for 8 days, and the modified reactive sand with a fineness of 30-50 mesh is obtained by crushing and sieving.

[0041] Example 3

[0042] An improved reactive sand, comprising the following raw materials by weight, white cement (P.W 42.5) 24.90 parts, silica fume 6.10 parts, triethanolamine 0.20 parts, nano-silica 0.80 parts, quartz powder with fineness of 150-200 mesh 45.20 parts, silane coupling agent 0.42 parts, carboxylic acid water reducing agent 0.28 parts, water 22.10 parts.

[0043] The preparation method of the improved reactive sand described in Example 3, comprising the following steps:

[0044] (1) 24.90 parts of white cement, 6.10 parts of silica fume, and 45.20 parts of quartz powder are uniformly mixed and stirred at a stirring speed of 120 r / min and a temperature of 15°C, 0.42 parts of atomized silane coupling agent is sprayed on the mixture, and the mixture is continuously stirred and mixed uniformly, and the silane coupling agent is allowed to react with the mixture for 28 hours;

[0045] (2) To the product obtained in step (1), 0.20 parts of triethanolamine, 0.80 parts of nano-silica, 0.28 parts of carboxylic acid water reducing agent, and 22.10 parts of water were added, and stirring was carried out at a speed of 80 r / min and a temperature of 8℃ for 1.5 h to prepare a viscous slurry;

[0046] (3) The viscous slurry in step (2) was first placed in a sealed device, and water was removed by negative pressure to remove the excess water in the slurry until the pressure in the sealed device was 30 KPa, and then the slurry was cured at room temperature for 6 days, and the modified reaction sand with a fineness of 30-50 mesh was obtained by crushing and sieving.

[0047] Comparative Example 1

[0048] The reaction sand of Comparative Example 1 is different from the reaction sand of Example 1 in that the reaction sand of Comparative Example 1 is not placed in a sealed device to remove the excess water in the slurry by negative pressure after being prepared into a viscous slurry, but is directly crushed and granulated after being cured at room temperature.

[0049] Comparative Example 2

[0050] The reaction sand of Comparative Example 2 is different from the reaction sand of Example 2 in that the reaction sand of Comparative Example 2 does not contain nano-silica and silica ash active ingredients. The remaining raw materials and preparation methods are the same as those of Example 2.

[0051] Comparative Example 3

[0052] The reaction sand of Comparative Example 3 is a commercially available ordinary reaction sand (using gypsum as a cementing material), which is compared with the modified reaction sand of Example 3.

[0053] In order to compare the performance differences between the examples and the comparative examples, related standard test methods were further used for testing, as follows:

[0054] 1. Reaction sand body strength

[0055] The slurry of Examples 1-3 and Comparative Examples 1-2 was vacuum dewatered, and 40mm×40mm×160mm test pieces were formed and cured for 6-8 days. The components such as gypsum, calcite powder, emulsion, and color paste were stirred, and 40mm×40mm×160mm test pieces were formed and sintered at high temperature. GB 17671 "Cement mortar strength test method" was used for testing, and the results are shown in Table 1.

[0056] Table 1. Reaction sand body strength

[0057] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Compressive strength / MPa 18.2 22.8 20.4 14.6 21.4 4.2 Flexural strength / MPa 3.6 5.2 4.3 3.1 5.1 1.1

[0058] Compared with Example 1, the strength of Comparative Example 1 is smaller, mainly because the water in Comparative Example 1 is not drained under negative pressure, which reduces the strength; compared with Example 2, the strength of Comparative Example 2 is close, and the active ingredient has little effect on the strength; compared with Example 3, the strength of Comparative Example 3 is small, mainly because the cementing materials are different, and Comparative Example 3 uses gypsum as the cementing material, while Example 3 uses P.W42.5 white cement as the cementing material.

[0059] 2. Bonding strength

[0060] The reaction sand is spread on the high molecular self-adhesive layer, rolled, and formed into an isolation layer to make a waterproof roll material, and then the concrete is poured and cured for 7 days. According to the test method of GB / T23457 “Pre-paved waterproof roll material”, the peel strength of the roll material and the concrete is tested, and the results are shown in Table 2.

[0061] Table 2 Bonding strength

[0062] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Bonding strength / (N / mm) 2.3 2.8 2.5 2.1 2.6 1.7

[0063] Examples 1-3 and Comparative Examples 1-2 all use cement as the cementing material, and the reaction sand has high strength, which forms a strong meshing action with the concrete after pouring the concrete, so the peel strength is large.

[0064] 3. Repair function to concrete

[0065] In order to test the repair function of the reaction sand to the concrete, the test method of GB18445 “Cement-based penetrating crystalline waterproof material” is used. The permeability pressure of the reference concrete test block is 0.3-0.4 MPa, and the concrete test block is completely pressed through the water on the permeability instrument. The small surface of the concrete test block is vertically immersed in water until the height of the test block is 2 / 3. The water-facing surface (large surface) of the concrete test block is fully wetted, and the reaction sand is uniformly spread at 150g-200g per square meter. The standard concrete curing room is cured for 28 days, and then the reaction sand is removed. The permeability of the concrete is tested, and the results are shown in Table 3.

[0066] Table 3 Repair function to concrete

[0067]

[0068] The test process imitates the actual use of the waterproofing membrane. In actual construction, the concrete is poured on the reactive sand of the waterproofing membrane, the active ingredients in the reactive sand fully penetrate into the capillary pores of the concrete, and in a strong alkaline and humid environment, the active silicon dioxide is hydrated to form silicic acid gel, which further reacts with the polyvalent ions of the cement hydration products to form crystalline substances, plug the capillary pores or repair the concrete cracks, and improve the impermeability. Because the water in the slurry is not promptly removed, the active silicon dioxide, silica fume, etc. in the slurry are hydrated and react with a large amount of cement in the reactive sand during the 6-8d curing process of the slurry, resulting in less penetration of the concrete after pouring and weak repairability. Comparative Example 2 does not add active ingredients, and the compressive strength of the concrete after 28d has almost no improvement. Comparative Example 3, the ordinary reactive sand, has no active ingredients and no repair function.

[0069] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An improved reactive sand characterized in that, The raw materials include the following weight parts: ordinary Portland cement or white cement 20-30 parts, silica fume 5-10 parts, triethanolamine 0.1-0.3 parts, nano-silica 0.5-1.0 parts, quartz powder 40-60 parts, silane coupling agent 0.3-0.6 parts, carboxylic acid water reducing agent 0.2-0.3 parts, and water 20-30 parts.

2. The improved reactive sand as claimed in claim 1 wherein, The raw materials include the following weight parts: ordinary Portland cement or white cement 22-28 parts, silica fume 6-8 parts, triethanolamine 0.1-0.2 parts, nano-silica 0.6-0.8 parts, quartz powder 45-55 parts, silane coupling agent 0.4-0.5 parts, carboxylic acid water reducing agent 0.2-0.3 parts, and water 22-28 parts.

3. The improved reactive sand according to any one of claims 1-2, wherein, The fineness of the quartz powder is 150-200 mesh.

4. A method of producing improved reactive sand according to any one of claims 1 to 3, characterized in that, The method comprises the following steps: (1) uniformly mixing cement, silica fume and quartz powder, spraying the atomized silane coupling agent on the mixture, continuously mixing and uniformly mixing, and allowing the silane coupling agent to react with the mixture by standing; (2) adding triethanolamine, nano-silica and carboxylic acid water reducing agent to the product obtained in step (1), uniformly stirring, and adding water to prepare viscous slurry; (3) solidifying the slurry, crushing and sieving to obtain modified reaction sand.

5. The method of claim 4, wherein the reactive sand is prepared by adding the dispersant to the sand. In step (1), the stirring and mixing speed is 40-120 r / min, and the stirring and mixing temperature is 15-30℃.

6. The method of claim 4, wherein the reactive sand is prepared by adding the dispersant to the sand. In step (1), the standing time is 20-28 h.

7. The method of claim 4, wherein the reactive sand is prepared by the steps of: In step (1), the reaction temperature of the silane coupling agent with the mixture is 15-30℃.

8. The method of claim 4, wherein the reactive sand is prepared by adding the dispersant to the sand. In step (2), the stirring speed is 80-160 r / min, and the stirring temperature is 4-8℃.

9. The method of claim 4, wherein the reactive sand is prepared by the steps of: In step (3), the viscous slurry is first placed in a closed device, and negative pressure water absorption treatment is performed to remove the excess water in the slurry until the pressure in the closed device is 20-30 KPa, and then normal temperature solidification is performed for 6-8 days, and the modified reaction sand is crushed to have a fineness of 30-50 mesh.

10. The use of the modified reaction sand according to any one of claims 1-9 in waterproofing membranes.

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