Waterproof and anti-crack cement mortar and preparation method thereof

Abstract

The application relates to a waterproof and anti-cracking cement mortar and a preparation method thereof, which are mainly prepared from the following components according to the following weight ratio: wherein the composite reinforcing fiber is mainly prepared from the following components according to the following weight ratio: the coupling agent diluent is prepared from aluminic ester coupling agent, ethanol and water in a mass ratio of 1:2:0.8-1.2. The application overcomes the weak waterproof and anti-cracking performance of the existing mortar, adopts the composite reinforcing fiber prepared from aluminic ester coupling agent, glass fiber and polypropylene resin, and through the synergistic effect of the composite reinforcing fiber, the polymer emulsion, other preferred components in the system and the use proportion, the application has the advantages of excellent anti-permeability and anti-cracking performance.

Description

Technical Field

[0001] This invention relates to a waterproof and crack-resistant cement mortar and its preparation method, which is applied in the field of cement mortar building material production. Background Technology

[0002] The descriptions in this section provide background information related to this disclosure only and do not constitute prior art. With the development of architectural forms and the increasing sophistication of consumers' tastes in building structures, the concept of wall insulation and energy conservation has gradually gained popularity. External wall insulation systems have become the mainstream form of wall insulation due to their numerous advantages. Currently, the main insulation materials available are inorganic materials such as insulating mortar, foamed cement boards, and rock wool boards. However, inorganic materials are highly absorbent; once they absorb water, their performance deteriorates, significantly reducing their insulation effect. This can lead to varying degrees of cracking, water seepage, hollowing, and detachment in the insulation and decoration of building facades, severely damaging the building's appearance and energy-saving effect, and greatly reducing its lifespan. Therefore, external wall insulation systems require a crack-resistant and waterproof protective layer with excellent impermeability and water resistance to provide good protection for the insulation layer. However, existing mortars are generally made by mixing cement, fine aggregates, water, and other materials in a certain proportion, resulting in relatively weak waterproof and crack-resistant properties (such as the pre-mixed mortar and its preparation method disclosed in CN201210194860.4). Therefore, providing a waterproof and crack-resistant cement mortar with both excellent impermeability and crack prevention properties has become an urgent task. Summary of the Invention

[0003] To overcome the shortcomings of existing mortars in terms of weak waterproof and crack-resistant performance, this invention provides a waterproof and crack-resistant cement mortar. It uses a composite reinforcing fiber prepared from an aluminate coupling agent, glass fiber and polypropylene resin. Through the synergistic effect of the composite reinforcing fiber, polymer emulsion, other preferred components in the system and their proportions, it has the advantages of both excellent impermeability and crack prevention performance.

[0004] The technical solution of the present invention is as follows:

[0005] A waterproof and crack-resistant cement mortar is mainly prepared from the following components in the following weight ratios:

[0006]

[0007] The composite reinforcing fiber is mainly prepared from the following components in the following weight ratios:

[0008]

[0009] The coupling agent dilution solution is prepared by mixing aluminate coupling agent, ethanol and water in a mass ratio of 1:2:0.8 to 1.2.

[0010] 1. The waterproof and crack-resistant cement mortar of this application uses composite reinforcing fibers prepared from aluminate coupling agent, glass fiber, and polypropylene resin. Through the synergistic effect of these composite reinforcing fibers, polymer emulsion, and other preferred components in the system, as well as their proportions, it possesses the advantages of both excellent impermeability and crack prevention properties. Preferably, the water used to prepare the waterproof and crack-resistant cement mortar is deionized water. The mechanism is as follows: Pre-modified glass fibers with an aluminate coupling agent and polypropylene resin are reacted to form composite reinforcing fibers. The addition of the aluminate coupling agent improves the compatibility of glass fibers in polypropylene resin and forms an aluminum hydroxide gel network within the composite reinforcing fibers, uniformly dispersing the glass fibers in the polypropylene resin. This improves the tendency of traditional polypropylene fibers to clump and roll during mechanical mixing, thus ensuring the crack resistance of the waterproof and crack-resistant cement mortar. Quicklime and water in the system react under carbon dioxide gas protection to produce calcium carbonate. The calcium carbonate reacts with the aluminum hydroxide in the composite reinforcing fibers to form tricalcium aluminate crystals that insert into the waterproof and crack-resistant cement mortar, forming a continuous waterproof layer. This significantly improves the impermeability and crack resistance of the waterproof and crack-resistant cement mortar.

[0011] The polymer emulsion is mainly prepared from the following components in the following weight ratios:

[0012]

[0013] In the polymer emulsion, butyl acrylate, 1,3,5-tris(4-vinylphenylbenzene), acrylic acid, and acrylamide polymerize under the action of an initiator via unsaturated bonds, forming a dendritic polymer network that further enhances the crack resistance of the waterproof and crack-resistant cement mortar. Preferably, deionized water is used to prepare the polymer emulsion.

[0014] The aggregate is prepared by mixing 70-140 mesh quartz sand and quartz powder with 4-5% residue on a 200 mesh sieve at a mass ratio of 0.3-0.7:1.

[0015] The cement is silicate cement.

[0016] The preferred cement is low in cost and readily available.

[0017] The initiator is sodium persulfate.

[0018] The glass fiber is waste glass fiber.

[0019] The selected glass fiber is more environmentally friendly.

[0020] The aluminate coupling agent is aluminate coupling agent DL-411.

[0021] The method for preparing the waterproof and crack-resistant cement mortar mainly includes the following steps performed in sequence:

[0022] (I) Preparation of composite reinforced fibers

[0023] (1) Preparation of coupling agent dilution: Mix aluminate coupling agent, ethanol and water evenly to obtain coupling agent dilution;

[0024] (2) Preparation of composite reinforced fibers

[0025] ① Add a 3-4 mol / L sodium hydroxide aqueous solution to the glass fiber to completely submerge the glass fiber. After ultrasonic dispersion for 1-2 hours, filter the solution. Then wash the glass fiber with clean water until the pH value is neutral, drain the solution, and you will get the cleaned glass fiber. Add the cleaned glass fiber to a muffle furnace, set the temperature to 400-450℃, and keep it at that temperature for 40-60 minutes. Then take out the glass fiber, grind it with a pulverizer, and pass it through an 80-100 mesh sieve to obtain glass fiber powder.

[0026] ② Place glass fiber powder, 25% ammonia water and coupling agent dilution into a ball mill and ball mill at 100-120℃ for 50-70 minutes to obtain pre-modified glass fiber;

[0027] ③ Add the pre-modified glass fiber and polypropylene resin to a high-speed mixer and mix evenly. Then, put them into a screw extruder for extrusion to obtain composite reinforcing fibers with a length of 5-7 mm.

[0028] (II) Preparation of Waterproof and Crack-Resistant Cement Mortar

[0029] (1) Take cement, aggregate, quicklime, composite reinforcing fiber, water reducing agent, thickener and defoamer, put them into a dry powder mixer and mix them evenly to obtain dry mix;

[0030] (2) Add the polymer emulsion to the mixer, start the mixer and adjust the speed to 400-600 r / min, stir for 10-20 min, then add water, adjust the mixer speed to 800-1200 r / min, stir for 3-5 min, and the liquid is obtained.

[0031] (3) Start the mixer and adjust the speed to 400-600 r / min. Under the protection of carbon dioxide gas, put the liquid agent into the mixer and add the dry mixture while stirring until a uniform mortar without lumps is formed, thus obtaining waterproof and crack-resistant cement mortar.

[0032] The method for preparing waterproof and crack-resistant cement mortar in this application is simple and easy to operate. Specifically, in the step of preparing the composite reinforcing fiber, the screw extruder is equipped with nine temperature control zones sequentially from the feed port to the extrusion die, with temperatures of 100℃, 120℃, 160℃, 180℃, 180℃, 180℃, 180℃, 210℃, and 210℃ respectively. The main screw speed of the screw extruder is 110 r / min, and the residence time of the composite reinforcing fiber in the screw extruder is 80 s. Under these preferred process parameters, the molding and discharge of the composite reinforcing fiber are smoother.

[0033] The preparation method of the polymer emulsion mainly includes the following steps performed in sequence:

[0034] (1) Start the mixer and adjust the speed to 400-600 r / min. Add water (48-51% of its total weight) and emulsifier (48-51% of its total weight) to the mixer and disperse for 2-4 min. Then adjust the speed to 800-1200 r / min and add butyl acrylate and 1,3,5-tris(4-vinylphenylbenzene) while stirring. Disperse for 4-6 min. Then add acrylic acid and acrylamide and continue to disperse for 15-25 min to obtain the pre-emulsion.

[0035] (2) Start the mixer and adjust the speed to 400-600 r / min. Add the remaining water and emulsifier to the mixer and heat to 80-90°C while stirring. Add 4-6% of the pre-emulsion by weight to the mixer and continue stirring for 3-5 minutes. Maintain the temperature at 80-90°C and the speed at 400-600 r / min, and continue adding 48-51% of the initiator by weight. React for 14-16 minutes. Then, add the remaining pre-emulsion dropwise, controlling the total dropwise time to 3-5 hours. When adding 1.5-1.5% of the pre-emulsion, the reaction time should be controlled to be 3-5 hours. At 2.5h, add the remaining initiator to the mixer; after the pre-emulsion is added, keep it warm for 50-70min, then cool it to 70-76℃ and add tert-butyl hydroperoxide and sodium bisulfite. The total time for adding tert-butyl hydroperoxide and sodium bisulfite should be controlled at 10-20min. After the addition is complete, keep it warm for 10-20min, and continue to cool it to 45-55℃. Adjust the pH value to 7-8 with a 10% sodium hydroxide solution, then cool it to below 45℃ and filter it through a 240-260 mesh filter to obtain the polymer emulsion.

[0036] The preparation method of the polymer emulsion is simple and easy to operate.

[0037] The emulsifiers in steps (1) and (2) of preparing the polymer emulsion include both nonionic and anionic emulsifiers, with a weight ratio of 1.56 to 1.667:1.

[0038] The best combination of emulsifiers and their proportions will result in better emulsification.

[0039] Compared with the prior art, this invention application has the following advantages:

[0040] 1) The waterproof and crack-resistant cement mortar of this application uses a composite reinforcing fiber prepared by aluminate coupling agent, glass fiber and polypropylene resin. Through the synergistic effect of the composite reinforcing fiber, polymer emulsion, other preferred components in the system and dosage ratio, it has the advantages of excellent impermeability and crack prevention.

[0041] 2) Butyl acrylate, 1,3,5-tris(4-vinylphenylbenzene), acrylic acid, and acrylamide in the polymer emulsion polymerize under the action of an initiator via unsaturated bonds, forming a dendritic polymer network, which further enhances the crack resistance of the waterproof and crack-resistant cement mortar.

[0042] 3) The preparation method of the waterproof and crack-resistant cement mortar is simple and easy to operate. Detailed Implementation

[0043] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] Example 1

[0045] The waterproof and crack-resistant cement mortar of the present invention is mainly prepared from the following components in the following weight ratio:

[0046]

[0047]

[0048] The composite reinforcing fiber is mainly prepared from the following components in the following weight ratios:

[0049]

[0050] The coupling agent dilution solution is prepared by mixing aluminate coupling agent, ethanol and water in a mass ratio of 1:2:1.

[0051] The polymer emulsion is mainly prepared from the following components in the following weight ratios:

[0052]

[0053] The aggregate is prepared by mixing 70-140 mesh quartz sand and quartz powder with 4% residue on a 200 mesh sieve at a mass ratio of 0.3:1.

[0054] The cement is silicate cement.

[0055] The initiator is sodium persulfate.

[0056] The glass fiber is waste glass fiber.

[0057] The aluminate coupling agent is aluminate coupling agent DL-411.

[0058] Water-reducing agent used is from BASF. Melamine-type sulfonated condensate powder;

[0059] The thickener used is hydroxypropyl methylcellulose with a viscosity of 40,000 cps in a 2% aqueous solution;

[0060] The defoamer used is P803 dry powder defoamer with 65% active ingredient.

[0061] The method for preparing the waterproof and crack-resistant cement mortar mainly includes the following steps performed in sequence:

[0062] (I) Preparation of composite reinforced fibers

[0063] (1) Preparation of coupling agent dilution: Mix aluminate coupling agent, ethanol and water evenly to obtain coupling agent dilution;

[0064] (2) Preparation of composite reinforced fibers

[0065] ① Add a 3 mol / L sodium hydroxide aqueous solution to the glass fiber to completely submerge the glass fiber. After ultrasonic dispersion for 1 hour, filter the solution. Then wash the glass fiber with clean water until the pH value is neutral and drain it to obtain the cleaned glass fiber. Add the cleaned glass fiber to a muffle furnace, set the temperature to 400℃, and keep it at that temperature for 40 minutes. Then take out the glass fiber, grind it with a pulverizer, and pass it through an 80-mesh sieve to obtain glass fiber powder.

[0066] ② Place glass fiber powder, 25% ammonia water and coupling agent dilution into a ball mill and ball mill at 100℃ for 50 min to obtain pre-modified glass fiber;

[0067] ③ Add the pre-modified glass fiber and polypropylene resin to a high-speed mixer and mix evenly. Then, put them into a screw extruder for extrusion to obtain a 5mm long composite reinforcing fiber.

[0068] (II) Preparation of Waterproof and Crack-Resistant Cement Mortar

[0069] (1) Take cement, aggregate, quicklime, composite reinforcing fiber, water reducing agent, thickener and defoamer, put them into a dry powder mixer and mix them evenly to obtain dry mix;

[0070] (2) Add the polymer emulsion to the mixer, start the mixer and adjust the speed to 400 r / min, stir for 10 min, then add water, adjust the mixer speed to 800 r / min, stir for 3 min, and the liquid is obtained.

[0071] (3) Start the mixer and adjust the speed to 400r / min. In the atmosphere of carbon dioxide gas, put the liquid agent into the mixer and add the dry mixture while stirring until a uniform mortar without lumps is formed, thus obtaining waterproof and crack-resistant cement mortar.

[0072] The preparation method of the polymer emulsion mainly includes the following steps performed in sequence:

[0073] (1) Start the mixer and adjust the speed to 400 r / min. Add water (50% of its total weight) and emulsifier (50% of its total weight) to the mixer and disperse for 2 min. Then adjust the speed to 800 r / min and add butyl acrylate and 1,3,5-tris(4-vinylphenylbenzene) while stirring. Disperse for 4 min. Then add acrylic acid and acrylamide and continue to disperse for 15 min to obtain the pre-emulsion.

[0074] (2) Start the mixer and adjust the speed to 400 r / min. Add the remaining water and emulsifier to the mixer and heat to 80°C while stirring. Add 4% of the pre-emulsion by weight to the mixer and continue stirring for 3 min. Maintain the temperature at 80°C and the speed at 400 r / min, and continue adding 50% of the initiator by weight. React for 14 min, then add the remaining pre-emulsion dropwise, controlling the total dropwise time to 3 h. Among these, when the pre-emulsion has been added for 1.5 h... Add the remaining initiator to the mixer; after the pre-emulsion is added, keep it warm for 50 minutes, then cool it down to 70°C and add tert-butyl hydroperoxide and sodium bisulfite. The total time for adding tert-butyl hydroperoxide and sodium bisulfite should be controlled within 10 minutes. After the addition is complete, keep it warm for 10 minutes, then continue to cool it down to 45°C. Adjust the pH value to 7 with a 10% sodium hydroxide solution, then cool it down to below 45°C and filter it through a 250-mesh filter to obtain the polymer emulsion.

[0075] In steps (1) and (2) of preparing the polymer emulsion, the emulsifiers include both nonionic and anionic emulsifiers, with a weight ratio of 1.625:1.

[0076] The screw extruder is equipped with nine temperature control zones sequentially from the feed port to the extrusion die, with temperatures of 100℃, 120℃, 160℃, 180℃, 180℃, 180℃, 180℃, 210℃, and 210℃ respectively. The main screw speed of the screw extruder is 110 r / min, and the residence time of the composite reinforcing fiber in the screw extruder is 80 s.

[0077] Example 2

[0078] The waterproof and crack-resistant cement mortar of the present invention is mainly prepared from the following components in the following weight ratio:

[0079]

[0080] The composite reinforcing fiber is mainly prepared from the following components in the following weight ratios:

[0081]

[0082] The coupling agent dilution solution is prepared by mixing aluminate coupling agent, ethanol and water in a mass ratio of 1:2:0.8.

[0083] The polymer emulsion is mainly prepared from the following components in the following weight ratios:

[0084]

[0085] An appropriate amount of 10% sodium hydroxide solution.

[0086] The aggregate is prepared by mixing 70-140 mesh quartz sand and quartz powder with 4.5% residue on a 200 mesh sieve at a mass ratio of 0.5:1.

[0087] The cement is silicate cement.

[0088] The initiator is sodium persulfate.

[0089] The glass fiber is waste glass fiber.

[0090] The aluminate coupling agent is aluminate coupling agent DL-411.

[0091] Water-reducing agent used is from BASF. Melamine-type sulfonated condensate powder;

[0092] The thickener used is hydroxypropyl methylcellulose with a viscosity of 40,000 cps in a 2% aqueous solution;

[0093] The defoamer used is P803 dry powder defoamer with 65% active ingredient.

[0094] The method for preparing the waterproof and crack-resistant cement mortar mainly includes the following steps performed in sequence:

[0095] (I) Preparation of composite reinforced fibers

[0096] (1) Preparation of coupling agent dilution: Mix aluminate coupling agent, ethanol and water evenly to obtain coupling agent dilution;

[0097] (2) Preparation of composite reinforced fibers

[0098] ① Add a 3.5 mol / L sodium hydroxide aqueous solution to the glass fiber to completely submerge the glass fiber. After ultrasonic dispersion for 1.5 hours, filter the solution. Then wash the glass fiber with clean water until the pH value is neutral and drain it to obtain the cleaned glass fiber. Add the cleaned glass fiber to a muffle furnace, set the temperature to 425℃, and keep it at that temperature for 50 minutes. Then take out the glass fiber, grind it with a pulverizer, and pass it through a 90-mesh sieve to obtain glass fiber powder.

[0099] ② Place glass fiber powder, 25% ammonia water and coupling agent dilution into a ball mill and ball mill at 110℃ for 60 min to obtain pre-modified glass fiber;

[0100] ③ Add the pre-modified glass fiber and polypropylene resin to a high-speed mixer and mix evenly. Then, put them into a screw extruder for extrusion to obtain a 6mm long composite reinforcing fiber.

[0101] (II) Preparation of Waterproof and Crack-Resistant Cement Mortar

[0102] (1) Take cement, aggregate, quicklime, composite reinforcing fiber, water reducing agent, thickener and defoamer, put them into a dry powder mixer and mix them evenly to obtain dry mix;

[0103] (2) Add the polymer emulsion to the mixer, start the mixer and adjust the speed to 500 r / min, stir for 15 min, then add water, adjust the mixer speed to 1000 r / min, stir for 4 min, and the liquid is obtained.

[0104] (3) Start the mixer and adjust the speed to 500r / min. In the atmosphere of carbon dioxide gas, put the liquid agent into the mixer and add the dry mixture while stirring until a uniform mortar without lumps is formed, thus obtaining waterproof and crack-resistant cement mortar.

[0105] The preparation method of the polymer emulsion mainly includes the following steps performed in sequence:

[0106] (1) Start the mixer and adjust the speed to 500 r / min. Add water (50% of its total weight) and emulsifier (50% of its total weight) to the mixer and disperse for 3 min. Then adjust the speed to 1000 r / min and add butyl acrylate and 1,3,5-tris(4-vinylphenylbenzene) while stirring. Disperse for 5 min. Then add acrylic acid and acrylamide and continue to disperse for 20 min to obtain the pre-emulsion.

[0107] (2) Start the mixer and adjust the speed to 500 r / min. Add the remaining water and emulsifier to the mixer and heat to 85°C while stirring. Add 5% of the pre-emulsion by weight to the mixer and continue stirring for 4 min. Maintain the temperature at 85°C and the speed at 500 r / min, and continue adding 50% of the initiator by weight. React for 15 min, then add the remaining pre-emulsion dropwise, controlling the total dropwise time to 4 h. When the pre-emulsion has been added for 2 h, Add the remaining initiator to the mixer; after the pre-emulsion is added, keep it warm for 60 minutes, then cool it down to 73°C and add tert-butyl hydroperoxide and sodium bisulfite. The total time for adding tert-butyl hydroperoxide and sodium bisulfite should be controlled within 15 minutes. After the addition is complete, keep it warm for 15 minutes, then continue to cool it down to 50°C. Adjust the pH value to 7.5 with a 10% sodium hydroxide solution, then cool it down to below 45°C and filter it through a 260-mesh filter to obtain the polymer emulsion.

[0108] The emulsifiers in steps (1) and (2) of preparing the polymer emulsion both include nonionic emulsifiers and anionic emulsifiers, with a weight ratio of 1.612:1.

[0109] The screw extruder is equipped with nine temperature control zones sequentially from the feed port to the extrusion die, with temperatures of 100℃, 120℃, 160℃, 180℃, 180℃, 180℃, 180℃, 210℃, and 210℃ respectively. The main screw speed of the screw extruder is 110 r / min, and the residence time of the composite reinforcing fiber in the screw extruder is 80 s.

[0110] Example 3

[0111] The waterproof and crack-resistant cement mortar of the present invention is mainly prepared from the following components in the following weight ratio:

[0112]

[0113] The composite reinforcing fiber is mainly prepared from the following components in the following weight ratios:

[0114]

[0115] The coupling agent dilution solution is prepared by mixing aluminate coupling agent, ethanol and water in a mass ratio of 1:2:1.2.

[0116] The polymer emulsion is mainly prepared from the following components in the following weight ratios:

[0117]

[0118] The aggregate is prepared by mixing 70-140 mesh quartz sand and 5% quartz powder retained on a 200 mesh sieve at a mass ratio of 0.7:1.

[0119] The cement is silicate cement.

[0120] The initiator is sodium persulfate.

[0121] The glass fiber is waste glass fiber.

[0122] The aluminate coupling agent is aluminate coupling agent DL-411.

[0123] Water-reducing agent used is from BASF. Melamine-type sulfonated condensate powder;

[0124] The thickener used is hydroxypropyl methylcellulose with a viscosity of 40,000 cps in a 2% aqueous solution;

[0125] The defoamer used is P803 dry powder defoamer with 65% active ingredient.

[0126] The method for preparing the waterproof and crack-resistant cement mortar mainly includes the following steps performed in sequence:

[0127] (I) Preparation of composite reinforced fibers

[0128] (1) Preparation of coupling agent dilution: Mix aluminate coupling agent, ethanol and water evenly to obtain coupling agent dilution;

[0129] (2) Preparation of composite reinforced fibers

[0130] ① Add a 4 mol / L sodium hydroxide aqueous solution to the glass fiber to completely submerge the glass fiber. After ultrasonic dispersion for 2 hours, filter the solution. Then wash the glass fiber with clean water until the pH value is neutral and drain to obtain the cleaned glass fiber. Add the cleaned glass fiber to a muffle furnace, set the temperature to 450℃, and keep it at that temperature for 60 minutes. Then take out the glass fiber, grind it with a pulverizer, and pass it through a 100-mesh sieve to obtain glass fiber powder.

[0131] ② Place glass fiber powder, 25% ammonia water (by mass percentage), and coupling agent dilution into a ball mill and ball mill at 120°C for 70 minutes to obtain pre-modified glass fiber;

[0132] ③ Add the pre-modified glass fiber and polypropylene resin to a high-speed mixer and mix evenly. Then, put them into a screw extruder for extrusion to obtain a 7mm long composite reinforcing fiber.

[0133] (II) Preparation of Waterproof and Crack-Resistant Cement Mortar

[0134] (1) Take cement, aggregate, quicklime, composite reinforcing fiber, water reducing agent, thickener and defoamer, put them into a dry powder mixer and mix them evenly to obtain dry mix;

[0135] (2) Add the polymer emulsion to the mixer, start the mixer and adjust the speed to 600 r / min, stir for 20 min, then add water, adjust the mixer speed to 1200 r / min, stir for 5 min, and the liquid is obtained.

[0136] (3) Start the mixer and adjust the speed to 600r / min. In the atmosphere of carbon dioxide gas, put the liquid agent into the mixer and add the dry mixture while stirring until a uniform mortar without lumps is formed, thus obtaining waterproof and crack-resistant cement mortar.

[0137] The preparation method of the polymer emulsion mainly includes the following steps performed in sequence:

[0138] (1) Start the mixer and adjust the speed to 600 r / min. Add water (50% of its total weight) and emulsifier (50% of its total weight) to the mixer and disperse for 4 min. Then adjust the speed to 1200 r / min and add butyl acrylate and 1,3,5-tris(4-vinylphenylbenzene) while stirring. Disperse for 6 min. Then add acrylic acid and acrylamide and continue to disperse for 25 min to obtain the pre-emulsion.

[0139] (2) Start the mixer and adjust the speed to 600 r / min. Add the remaining water and emulsifier to the mixer and heat to 90°C while stirring. Add 6% of the pre-emulsion by weight to the mixer and continue stirring for 3-5 minutes. Maintain the temperature at 80-90°C and the speed at 400-600 r / min, and continue adding 50% of the initiator by weight. React for 16 minutes, then add the remaining pre-emulsion dropwise, controlling the total dropwise time to 5 hours. At 2.5h, the remaining initiator was added to the mixer; after the pre-emulsion was added, it was kept at the temperature for 70min, then cooled to 76℃ and tert-butyl hydroperoxide and sodium bisulfite were added. The total time for adding tert-butyl hydroperoxide and sodium bisulfite was controlled within 20min. After the addition was completed, it was kept at the temperature for 20min, and then cooled to 55℃. The pH value was adjusted to 8 with a 10% sodium hydroxide solution, and then cooled to below 45℃. The mixture was then filtered through a 240-mesh filter to obtain the polymer emulsion.

[0140] The emulsifiers in steps (1) and (2) of preparing the polymer emulsion include both nonionic and anionic emulsifiers, with a weight ratio of 1.6:1.

[0141] Raw material information involved in each embodiment:

[0142] Cement: Portland cement PO42.5 (density 3.07 g / cm³) 3 The residue on an 80μm sieve is 4.8%, the content of dihydrate gypsum is about 4%, the content of limestone and fly ash is 10%, and the standard consistency is 26%. Fujian Jianyang Conch Cement Co., Ltd.

[0143] Butyl acrylate (BA), acrylamide (AM), acrylic acid (AA): Beijing Dongfang Chemical Plant, purity 99%;

[0144] Anionic emulsifier: Cytec A-102, active ingredient content 30%;

[0145] Nonionic emulsifier: Clariant LCN 407, 70% active ingredient content;

[0146] Quartz sand: 70-140 mesh (mixed particle size), moisture content 0.5%;

[0147] Quartz powder: 4-5% residue on 200-mesh sieve, 0% moisture content, from Fogang Quartz Sand Factory, Guangdong.

[0148] Polypropylene resin: Yangzi Petrochemical S400;

[0149] Defoamer: P803 dry powder, 65% active ingredient, a nonionic surfactant suitable for dry-mixed cement mortar containing liquid hydrocarbons, polyethylene glycol and inorganic carrier, MUNZING-CHEMIE GmbH, Germany;

[0150] Thickener: Hydroxypropyl methylcellulose PMC-15US, 2% aqueous solution viscosity 15000cps (Brookfield RVT, 20℃, average test value), Samsung Corporation, Korea; Hydroxypropyl methylcellulose: P4123, 2% aqueous solution viscosity 40000cps (Brookfield RVT, 20℃, average test value), Hercules Corporation;

[0151] 1,3,5-Tris(4-vinylphenylbenzene): Jilin Zhongke Science & Technology Co., Ltd.

[0152] The screw extruder is equipped with nine temperature control zones sequentially from the feed port to the extrusion die, with temperatures of 100℃, 120℃, 160℃, 180℃, 180℃, 180℃, 180℃, 210℃, and 210℃ respectively. The main screw speed of the screw extruder is 110 r / min, and the residence time of the composite reinforcing fiber in the screw extruder is 80 s.

[0153] Experimental data:

[0154] Detection method:

[0155] Waterproofing: Waterproof and crack-resistant cement mortar prepared with the same mass as the example and comparative example was tested for waterproofing performance according to the 28-day water resistance test in GB / T25181.

[0156] Crack resistance: Waterproof and crack-resistant cement mortar prepared by the same mass of the example and comparative example was tested according to JC / T951 for crack index (mm).

[0157] Comparative Example 1

[0158] The difference between Comparative Example 1 and Example 2 is that the coupling agent diluent in the preparation of the composite reinforcing fiber in Comparative Example 1 uses silane coupling agent KH550 in the same proportion instead of aluminate coupling agent.

[0159] Comparative Example 2

[0160] The difference between Comparative Example 2 and Example 2 is that styrene was used instead of 1,3,5-tris(4-vinylphenylbenzene) in the same proportion of raw materials for preparing the polymer emulsion in Comparative Example 2.

[0161] Comparative Example 3

[0162] The difference between Comparative Example 3 and Example 2 is that quicklime was not used in the raw materials for preparing waterproof and crack-resistant cement mortar in Comparative Example 3.

[0163] Comparative Example 4

[0164] The difference between Comparative Example 4 and Example 2 is that in step (3) of preparing waterproof and crack-resistant cement mortar in Comparative Example 4, the mixing of dry mix and liquid agent is carried out under air protection conditions, rather than under carbon dioxide protection conditions.

[0165] The test results are shown in Table 1:

[0166] Table 1 Performance test results of each embodiment

[0167]

[0168]

[0169] As can be seen from Table 1, the waterproof and crack-resistant cement mortars prepared in Examples 1-3 have both excellent impermeability (waterproofness) and crack resistance, and their overall performance is superior to that of each example. A comparison of the experimental data from Examples 1-3 and Comparative Example 1 reveals that the waterproof and crack-resistant cement mortar prepared using the aluminate coupling agent DL-411 to prepare a diluted coupling agent solution (composite UV absorber) exhibits good impermeability and crack resistance. The experimental data from Examples 1-3 and Comparative Example 2 shows that the waterproof and crack-resistant cement mortar prepared using water, emulsifier, butyl acrylate, 1,3,5-tris(4-vinylphenyl)benzene, acrylic acid, acrylamide, and initiator exhibits good crack resistance. The experimental data from Examples 1-3 and Comparative Example 3 shows that the waterproof and crack-resistant cement mortar prepared using mud, aggregate, quicklime, composite reinforcing fiber, water-reducing agent, thickener, defoamer, polymer emulsion, and water exhibits good impermeability and crack resistance. The experimental data from Examples 1-3 and Comparative Example 4 shows that the waterproof and crack-resistant cement mortar prepared by mixing dry mix and liquid agent under carbon dioxide gas protection exhibits good impermeability.

Claims

1. A waterproof and crack-resistant cement mortar, characterized in that: It is mainly prepared from the following components in the following weight ratios: 90-110 parts cement 85-95 parts aggregate 0.1 to 0.3 parts quicklime 1-5 parts of composite reinforcing fiber Water-reducing agent 0.3~0.5 parts Thickener 0.1~0.3 parts 0.3-0.5 parts of defoamer 50-54 parts of polymer emulsion 16-18 parts water; The composite reinforcing fiber is mainly prepared from the following components in the following weight ratios: 0.28~1.24 parts of coupling agent dilution solution 9-11 parts glass fiber 0.01~0.03 parts of ammonia solution with a mass percentage concentration of 25%. 50-100 parts of polypropylene resin; The coupling agent dilution solution is prepared by mixing aluminate coupling agent, ethanol and water in a mass ratio of 1:2:0.8~1.2; The polymer emulsion is mainly prepared from the following components in the following weight ratios: 48-52 parts water Emulsifier 1.26~1.3 parts 27-32 parts of butyl acrylate 1,3,5-Tris(4-vinylphenyl)benzene 15-21 parts Acrylic acid 0.48~0.5 parts Acrylamide 0.96~1 part Initiator 0.13~0.22 parts 0.03~0.04 parts of tert-butyl hydroperoxide Sodium bisulfite 0.03~0.04 parts An appropriate amount of 10% sodium hydroxide solution; The preparation method of the waterproof and crack-resistant cement mortar mainly includes the following steps in sequence: (1) Take cement, aggregate, quicklime, composite reinforcing fiber, water-reducing agent, thickener and defoamer, put them into a dry powder mixer and mix them evenly to obtain dry mix; (2) Add the polymer emulsion to the mixer, start the mixer and adjust the speed to 400~600 r / min, stir for 10~20 min, then add water, adjust the mixer speed to 800~1200 r / min, stir for 3~5 min, and the liquid is obtained; (3) Start the mixer and adjust the speed to 400~600r / min. Under the protection of carbon dioxide gas, put the liquid agent into the mixer and add the dry mixture while stirring until a uniform mortar without lumps is formed, thus obtaining waterproof and crack-resistant cement mortar.

2. The waterproof and crack-resistant cement mortar according to claim 1, characterized in that: The aggregate is prepared by mixing 70-140 mesh quartz sand and quartz powder with 4-5% residue on a 200 mesh sieve at a mass ratio of 0.3-0.7:

1.

3. The waterproof and crack-resistant cement mortar according to claim 1, characterized in that: The cement is silicate cement.

4. The waterproof and crack-resistant cement mortar according to claim 1, characterized in that: The initiator is sodium persulfate.

5. The waterproof and crack-resistant cement mortar according to claim 1, characterized in that: The glass fiber is waste glass fiber.

6. The waterproof and crack-resistant cement mortar according to claim 1, characterized in that: The aluminate coupling agent is aluminate coupling agent DL-411.

7. The method for preparing waterproof and crack-resistant cement mortar according to any one of claims 1-6, characterized in that: The main steps are as follows, performed in sequence: (I) Preparation of composite reinforcing fibers (1) Preparation of coupling agent dilution: Mix aluminate coupling agent, ethanol and water evenly to obtain coupling agent dilution; (2) Preparation of composite reinforcing fibers ① Add a 3-4 mol / L sodium hydroxide aqueous solution to the glass fiber to completely submerge the glass fiber. After ultrasonic dispersion for 1-2 hours, filter the solution. Then wash the glass fiber with clean water until the pH value is neutral, drain the solution, and you will get the cleaned glass fiber. Add the cleaned glass fiber to a muffle furnace, set the temperature to 400-450°C, and keep it at that temperature for 40-60 minutes. Then take out the glass fiber, grind it with a pulverizer, and pass it through an 80-100 mesh sieve to obtain glass fiber powder. ② Place glass fiber powder, ammonia water with a mass percentage concentration of 25% and coupling agent dilution into a ball mill and ball mill at 100~120℃ for 50~70 minutes to obtain pre-modified glass fiber; ③ Add the pre-modified glass fiber and polypropylene resin to a high-speed mixer and mix evenly. Then, put them into a screw extruder for extrusion to obtain composite reinforcing fibers with a length of 5-7 mm. (II) Preparation of waterproof and crack-resistant cement mortar (1) Take cement, aggregate, quicklime, composite reinforcing fiber, water-reducing agent, thickener and defoamer, put them into a dry powder mixer and mix them evenly to obtain dry mix; (2) Add the polymer emulsion to the mixer, start the mixer and adjust the speed to 400~600 r / min, stir for 10~20 min, then add water, adjust the mixer speed to 800~1200 r / min, stir for 3~5 min, and the liquid is obtained; (3) Start the mixer and adjust the speed to 400~600r / min. Under the protection of carbon dioxide gas, put the liquid agent into the mixer and add the dry mixture while stirring until a uniform mortar without lumps is formed, thus obtaining waterproof and crack-resistant cement mortar. The preparation method of the polymer emulsion mainly includes the following steps performed in sequence: (1) Start the mixer and adjust the speed to 400~600r / min. Add water (48-51% of its total weight) and emulsifier (48-51% of its total weight) to the mixer and disperse for 2~4min. Then adjust the speed to 800~1200r / min and add butyl acrylate and 1,3,5-tris(4-vinylphenyl)benzene while stirring. Disperse for 4~6min. Then add acrylic acid and acrylic amide and continue to disperse for 15~25min to obtain the pre-emulsion. (2) Start the mixer and adjust the speed to 400~600 r / min. Add the remaining water and emulsifier to the mixer and heat to 80~90℃ while stirring. Add 4~6% of the pre-emulsion by weight to the mixer and continue stirring for 3~5 min. Maintain the temperature at 80~90℃ and the speed at 400~600 r / min, and continue adding 48~51% of the initiator by weight. React for 14~16 min, then add the remaining pre-emulsion dropwise, controlling the total dropwise time to 3~5 h. When adding 1.5~ At 2.5h, add the remaining initiator to the mixer; after the pre-emulsion is added, keep it warm for 50-70min, then cool it to 70-76℃ and add tert-butyl hydroperoxide and sodium bisulfite. The total time for adding tert-butyl hydroperoxide and sodium bisulfite should be controlled at 10-20min. After the addition is complete, keep it warm for 10-20min, and continue to cool it to 45-55℃. Adjust the pH value to 7-8 with a 10% sodium hydroxide solution, then cool it to below 45℃ and filter it through a 240-260 mesh filter to obtain the polymer emulsion.

8. The method for preparing waterproof and crack-resistant cement mortar according to claim 7, characterized in that: The emulsifiers in steps (1) and (2) of preparing the polymer emulsion include both nonionic and anionic emulsifiers, with a weight ratio of 1.56 to 1.667:1.

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