CN113526931A

CN113526931A - Outer wall anti-cracking mortar

Info

Publication number: CN113526931A
Application number: CN202110895223.9A
Authority: CN
Inventors: 谢咏宸; 李炬轩; 徐观明; 黄晓东; 廖房朋; 钟林峰
Original assignee: Longnan Caiyi Decoration Material Factory
Current assignee: Longnan Caiyi Decoration Material Factory
Priority date: 2021-08-05
Filing date: 2021-08-05
Publication date: 2021-10-22

Abstract

The invention provides a preparation method of external wall anti-crack mortar. The modified fiber is added to improve the crack resistance of the mortar, and the surface of the fiber is modified, so that the fiber can be uniformly dispersed in the mortar, and the effect of the fiber can be exerted. The mortar has large deformation difference caused by the change of temperature difference due to the overlarge difference of the heat conductivity coefficients of the mortar and the heat insulation board, and is easy to crack. The modified sealing agent is added, so that the agglomeration phenomenon in the mortar is reduced, and the modified sealing agent contains flame-retardant components, so that the plastic sand is prevented from spontaneous combustion at high temperature, and the safety coefficient of the wall surface is improved.

Description

Outer wall anti-cracking mortar

Technical Field

The invention relates to the technical field of building materials, in particular to dry-mixed external wall anti-cracking mortar.

Background

With the deepening of the popularization and application work of the energy-saving buildings, the external thermal insulation system of the external wall is widely applied. The external thermal insulation system of the external wall has the problems of wall leakage, ventilation, peeling and the like due to the phenomena of hollowing, cracking, falling and the like of the external thermal insulation layer of the external wall caused by large change of the environmental temperature and humidity, large self shrinkage or improper construction method. One of the most effective methods for solving the problem is to apply anti-crack mortar on the basis of the heat insulation layer. The outer wall anti-cracking mortar is formed by uniformly stirring and mixing a cementing material, a filler, fibers and an additive according to a certain formula, and can meet the requirement of a polymer mortar material which deforms to a certain extent and does not crack. The anti-cracking mortar is an important component of an anti-cracking protective layer in a heat insulation system, and the anti-cracking mortar is coated on the surface of a heat insulation layer, and a grid cloth (or a steel wire mesh) is clamped between the anti-cracking mortar and the heat insulation layer to protect the heat insulation layer and prevent cracking. Waterproof and impact-resistant effects. The quality of the heat insulation system directly influences the use effect and the service life of the whole heat insulation system.

But because the coefficient of heat conductivity of the plastering mortar and the heat insulation board is too different: when the thermal conductivity coefficient of the material is lower, the heat-insulating capability of the material is stronger, the thermal conductivity coefficient of the expanded polystyrene board is 0.042W/(m.K), the thermal conductivity coefficient of the common anti-crack mortar is 0.93W/(m.K), and the difference of the thermal conductivity coefficients of the two layers of materials is 22 times. When direct sunlight irradiates on the surface of the plastering mortar in summer, the temperature of the plastering mortar is increased rapidly, the surface temperature is as high as 50-70 ℃, the temperature is reduced to about 15 ℃ when sudden rainfall occurs, the temperature difference can reach 35-55 ℃, the difference of the deformation of a plastering mortar layer is large due to the temperature difference change and the influence of outdoor temperatures in day and night and seasons, and the plastering mortar is easy to crack. At present, the main measures for overcoming the cracking resistance of the insulating layer include adopting fibers to enhance the cracking resistance, improving the flexibility and the viscosity through the modification of organic polymers, reducing the contractibility by adopting an expanding agent and the like. The cost of the various methods is greatly increased, and the process is very complicated. Aiming at the problems, the invention provides a preparation method of modified plastic sand, wherein the thermal conductivity coefficient of plastic particles is 0.034W/(m.K), and when the modified plastic sand is applied to mortar, the thermal conductivity coefficient difference between anti-crack mortar and a heat-insulation plate is effectively reduced, and the cracking of the mortar is fundamentally prevented; meanwhile, the preparation method of the modified sealing agent is also provided, so that the mortar has good crack resistance.

Disclosure of Invention

The invention aims to: provides an outer wall anti-crack mortar and a preparation method thereof.

Second object of the invention: provides a preparation method of modified fiber in the outer wall anti-crack mortar.

The third object of the present invention: provides a preparation method of modified plastic cement sand in mixed sand in outer wall anti-cracking mortar.

The fourth object of the present invention: provides a preparation method of a modified sealing agent in outer wall anti-cracking mortar.

The invention is realized by the following technical scheme:

an outer wall anti-cracking mortar comprises the following raw materials of P.O42.5 cement: 300-350 parts of machine-made sand: 650 parts of 325-mesh heavy calcium powder: 0-50 parts of cellulose ether: 3-5 parts of modified fiber: 3-5 parts of latex powder: 12-18 parts of modified sealing agent and 1-3 parts of modified sealing agent.

The modified fiber is as follows: 15-25 parts of polypropylene fiber, 30-35 parts of lignin fiber, 10-15 parts of steel nano fiber, 10-15 parts of brucite fiber, 10-15 parts of sepiolite fiber, 5-15 parts of 10mm carbon fiber and 5-8 parts of 6mm basalt fiber are mixed and modified to obtain the composite fiber.

The specific modification process of the fiber comprises the following steps:

1) respectively chopping polypropylene fibers, steel nano fibers and brucite fibers into chopped fibers with the length of 10mm, adding lignin fibers, sepiolite fibers, 10mm carbon fibers and 6mm basalt fibers, and uniformly mixing the materials in proportion;

2) soaking the uniformly mixed fibers in a sol solution, slowly heating to 70-75 ℃ at the speed of 1-3 ℃/min, carrying out heat preservation reaction for 3h, carrying out primary modification activation on the surfaces of the mixed fibers, and taking out for later use;

3) adding a modifier into the mixed fiber treated in the step 2), adding an ethanol solution, heating to 50 ℃ at the speed of 1-2 ℃/min, stirring while heating, carrying out heat preservation reaction for 5 hours, standing for 1d, and taking out for later use;

4) putting the mixed fiber prepared in the step 3) into 15% of water glass gel, putting the mixed fiber into a water bath kettle, heating the mixed fiber to 40-45 ℃ in a water bath, and carrying out heat preservation reaction for 5 hours to obtain the fiber.

Wherein the sol solution is a mixed solution prepared from 5-8% of NCC sol, 7-10% of polyvinylpyrrolidone hydrosol and 7-10% of chitosan hydrosol according to the volume ratio of 4:3: 3.

The preparation of the modifier comprises the following steps:

a. adding dichloromethane into 15-20 parts of sodium metaphosphate and 10-13 parts of dioctyl sodium sulfosuccinate, heating to 130 ℃ at the speed of 3-5 ℃/min, and carrying out heat preservation reaction for 3 hours to obtain a reactant a;

b. adding 5-8 parts of tributyl phosphate and 1, 2-dichloromethane solvent into the reactant a, heating to 80 ℃ at the speed of 3-5 ℃/min, keeping the temperature for 5 hours, dropwise adding 8-15 parts of 1, 3-dicyclohexylcarbodiimide into the reactant a at the speed of 20-25 drops/min, stirring uniformly, slowly heating to 120 ℃ at the heating speed of 1-2 ℃/min, keeping the temperature for 4 hours, and obtaining a reactant b;

c. adding 8-12 parts of sodium alcohol ether carboxylate into the reactant b, adding an acetone solvent, slowly heating to 130 ℃ at the speed of 1-3 ℃/min, and carrying out heat preservation reaction for 4h to obtain a reactant c;

d. and (3) adding 12-15 parts of guanylurea phosphate into the reactant c, adding a methanol solution, heating to 85-90 ℃ at the speed of 7-10 ℃/min, and carrying out heat preservation reaction for 4-6 hours to obtain the guanylurea phosphate.

The machine-made sand is mixed sand of 70-80 parts of 100-sand 120-mesh quartz sand and 30-40 parts of 100-sand 120-mesh modified plastic sand.

The preparation method of the modified plastic sand comprises the following steps:

1) putting the plastic particles into a viscous solution, heating to 40 ℃, soaking for 6 hours, and taking out for later use;

2) adding 8-12 parts of potassium oleate and 5-9 parts of 4-methyl-2-pentanol into ethanol solution, placing the mixture into a homogenizing reaction kettle for homogenizing treatment, placing the treated mixture into a reactor, slowly heating to 105 ℃ and 120 ℃ at the speed of 1-3 ℃/min, and carrying out heat preservation reaction for 3 hours to obtain an intermediate product i;

3) adding 12-15 parts of diethylamino methyl triethoxysilane into the intermediate product i, adding an ethyl acetate solvent, heating to 90-95 ℃ at the speed of 5-8 ℃/min, and carrying out heat preservation reaction for 4h to obtain an intermediate product ii;

4) adding 12-15 parts of chromium acetylacetonate and a toluene solution into the intermediate product ii, and putting the mixture into a high-pressure reaction kettle, wherein the pressure is 0.8-0.9Mpa, the temperature is 95-105 ℃, and the temperature is kept for 5 hours to react to obtain an intermediate product iii;

5) adding 15-20 parts of the plastic particle prepared in the step 1) into 5-7 parts of the intermediate product iii, adding an N, N-dimethylformamide solution, uniformly stirring, adding 15-20 parts of microcrystalline paraffin, slowly heating to 45 ℃, and uniformly stirring to obtain the plastic particle.

Wherein the viscous solution is a mixed solution of 15-20% of carboxymethyl cellulose solution and 8-10% of calcium lignosulfonate solution in a volume ratio of 3: 2.

The preparation of the modified sealing agent comprises the following steps:

1) putting 12-15 parts of phenolic propane epoxy resin, 5-10 parts of cyanuric acid epoxy resin and 5-8 parts of resorcinol epoxy resin into a homogenization reaction kettle, adding ethyl acetate, carrying out homogenization treatment on the mixture, and pouring out the treated mixture for later use;

2) adding 5-10 parts of polycarbonate, 3-5 parts of polymethyl methacrylate, adding trichloromethane, slowly heating to 200-220 ℃ at the speed of 1-3 ℃/min, and carrying out heat preservation reaction for 8h to obtain a product a;

3) adding 5-8 parts of 4-methyl-2-pentanol and 7-15 parts of hexadecyl trimethoxy silane into the product a, adding toluene, heating to 120 ℃ at the speed of 5-7 ℃/min, and carrying out heat preservation reaction for 6 hours to obtain a product b;

4) adding 5-8 parts of disodium lauroamphodiacetate into the product b, adding a propanol solution into the product b, quickly heating to 150 ℃, and carrying out heat preservation reaction for 6 hours to obtain a product c;

5) and (3) adding the mixture prepared in the step (1) into the product c, mixing the mixture and the product c, pouring the mixture into a high-pressure reaction kettle, and keeping the temperature at 120 ℃ under the pressure of 0.8-1.0Mpa for reaction for 3 hours to obtain the catalyst.

The invention has the following advantages:

1) the fibers selected in the invention have the following advantages:

polypropylene fibers have the disadvantage of being poorly fire resistant and sensitive to oxygen and sunlight. Flammability, leading to reduced fire resistance of the concrete; for monofilament polypropylene fibers, the bond between the fiber and the matrix is poor, resulting in lower pull-out strength. And the polypropylene fiber has low elastic modulus (about 1/10 of concrete), certain thickening effect and weak interface effect, which are all unfavorable factors for the mortar strength. Although polypropylene fibers can prevent early mortar from plastic cracking, they do not have a reinforcing effect on the hardened mortar. Therefore, other fibers need to be added to perform composite modification with the polypropylene-based fibers, so that the polypropylene-based fibers can be effectively compounded with other fibers.

② the lignin fiber is organic fiber obtained by chemical treatment of natural wood, the appearance is cotton-like, and is white or grey white. The treatment temperature is up to more than 250 ℃, so the material is a chemically very stable substance under the common conditions, is not corroded by common solvents, acids and alkalis, has the excellent quality of no toxicity, no odor, no pollution and no radioactivity, does not influence the environment, is harmless to the human body, and belongs to a green and environment-friendly product. The microstructure of the fiber is strip-shaped and bent, uneven and porous, the cross part is flat, and the fiber has good toughness, dispersibility and chemical stability, strong water absorption capacity and excellent thickening and anti-cracking performance. Has good effects of preventing the coating from cracking, improving the water retention, improving the production stability and the construction suitability, increasing the strength, enhancing the adhesive force to the surface and the like. The technical effects are as follows: thixotropic, protective, absorptive, carrier and filler.

And thirdly, brucite fiber is the best alkali resistance in naturally formed inorganic fiber. It is soluble in strong acid and is susceptible to attack in humid environments. The brucite fiber has the tensile strength of 902MPa and belongs to a medium-strength fiber material. The elastic modulus is 13800MPa, and the product has certain brittleness. The Vickers hardness is 50.4-260.5, and the material has obvious anisotropy. Is easy to be ground into fine powder. Theoretical relative density 2.39

The basalt fiber is typical silicate fiber, is easy to disperse when being mixed with cement concrete and mortar, and the freshly mixed basalt fiber concrete has stable volume, good workability, good durability, excellent high temperature resistance, seepage prevention, crack resistance and impact resistance. Basalt fibers are the genuine "multifunctional" fibers. Such as acid resistance and alkali resistance, low temperature resistance and high temperature resistance, heat insulation, electric insulation and sound insulation, tensile strength exceeds that of large-tow carbon fibers, elongation at break is better than that of small-tow carbon fibers, and the composite material has high compressive strength and shear strength and excellent comprehensive performance such as adaptability to severe environment and ageing resistance.

The sepiolite fiber bonding and blending is the preferred substitute of asbestos in the textile industry, and has sealing property and high strength and heat resistance. It has stable chemical performance, no ageing, high strength and high corrosion resistance.

Sixthly, steel nano fiber: the steel wire is pressed into a certain shape and cut into steel fibers which are added into the cement-based material, so that the tensile property, the bending resistance, the impact resistance, the crack resistance, the explosion resistance, the toughness and other properties of the cement-based material can be improved. The addition of the micro steel fibers greatly reduces the brittleness of the mortar, so that the mortar has the characteristics of high strength, high toughness and excellent durability.

The carbon fiber is lighter than aluminum and higher than steel in strength, has specific gravity of 1/4 times that of iron and 10 times that of iron, and has high chemical performance, high corrosion resistance, high temperature and low temperature resistance, high radiation resistance and high deodorizing performance.

Although the fibers have good performances, when the fibers are applied to mortar, phenomena such as entanglement and agglomeration can occur due to the environment, the uniformity of the mortar is reduced, the agglomeration phenomenon occurs in the mortar, and meanwhile, the sagging resistance of the mortar is reduced, so the fibers are subjected to surface modification, can be uniformly dispersed in the mortar, and can exert the effects of the fibers. The modifier has dispersive molecules, so that the fibers can be effectively dispersed, and the fibers are not entangled with each other, so that the agglomeration phenomenon occurs in the mortar. The fiber is soaked in the hydrosol, so that the surface of the nanofiber can be activated and protected, and the viscosity of the fiber is increased.

2) Because the coefficient of thermal conductivity of the plastering mortar and the insulation board is too different: when the thermal conductivity coefficient of the material is lower, the heat-insulating capability of the material is stronger, the thermal conductivity coefficient of the expanded polystyrene board is 0.042W/(m.K), the thermal conductivity coefficient of the common anti-crack mortar is 0.93W/(m.K), and the difference of the thermal conductivity coefficients of the two layers of materials is 22 times. When direct sunlight irradiates on the surface of the plastering mortar in summer, the temperature of the plastering mortar is increased rapidly, the surface temperature is as high as 50-70 ℃, the temperature is reduced to about 15 ℃ when sudden rainfall occurs, the temperature difference can reach 35-55 ℃, the difference of the deformation of a plastering mortar layer is large due to the temperature difference change and the influence of outdoor temperatures in day and night and seasons, and the plastering mortar is easy to crack. The plastic particles have good heat absorption effect, the heat conductivity coefficient is 0.034W/(m.K), the heat conductivity coefficient difference between the anti-crack mortar and the heat insulation plate is effectively reduced, and the cracking of the mortar is fundamentally prevented. The plastic particles are light in weight, so that the overall weight of a building is effectively reduced, the thermal insulation and sound insulation effects are achieved, and the mortar prepared by mixing the plastic particles with quartz sand has the thermal insulation and heat insulation effects. Ordinary rubber and plastic particles can not be effectively adhered to quartz sand due to the nature of the particles, and the plastic particles are prevented from falling off due to the problem of viscosity. The fine sand is selected for mortar, so that the surface of the mortar can be smooth without being coated by cement mortar of an external wall, the color of the mortar is consistent, the mortar is easy to be coated, and the mortar is not used for the surface of the mortar to be decorated by a finish coat.

3) In the mortar, modified fibers and modified rubber-plastic sand exist, when the direct solar radiation is applied to the surface of plastering mortar in summer, the temperature of the plastering mortar is increased sharply, the surface temperature is up to 50-70 ℃, in a high-temperature environment, the modified fibers can react with a surface modifier of the modified rubber-plastic sand, particularly the mortar on the surface can be agglomerated, and the surface of the mortar is uneven; the inventor finds that the sealing agent can effectively reduce the reaction between the surface of the mortar and the outside after adding the sealing agent into the mortar, but the sealing agent can permeate into the mortar under the condition of sufficient sunlight and react with the inside of the mortar, so that the viscosity of the mortar is reduced, the cohesive force in the mortar is reduced, the adhesion between the mortar and a wall is reduced, and the mortar is easy to fall off. Therefore, the modified sealing agent prepared by the inventor does not react with the modified fiber and the modified plastic sand in the mortar under the irradiation of sunlight, reduces the agglomeration phenomenon in the mortar and ensures the flatness of the surface of the mortar. The modified sealing agent contains the water-retaining agent, so that water can be effectively retained, mortar can be easily trowelled when the outer layer is coated, a trowelling surface does not need to be additionally coated, the using amount of the mortar is reduced, the cost is reduced, and the problem that the decorative surface layer and the trowelling surface layer cannot be effectively bonded is avoided. And the modified sealing agent contains flame-retardant components, so that the plastic sand is prevented from spontaneous combustion at high temperature, the fireproof performance of the building is improved, and the safety factor of the wall surface is improved.

Detailed description of the invention

Example 1

An outer wall anti-cracking mortar comprises the following raw materials of P.O42.5 cement: 325 parts of machine-made sand: 650 parts of 325-mesh heavy calcium powder: 25 parts of cellulose ether: 4 parts of modified fiber: 4 parts of latex powder: 15 parts of modified sealing agent and 2 parts of modified sealing agent.

The modified fiber is as follows: the fiber is prepared by mixing and modifying 20 parts of polypropylene fiber, 33 parts of lignin fiber, 13 parts of steel nano fiber, 13 parts of brucite fiber, 13 parts of sepiolite fiber, 10 parts of 10mm carbon fiber and 7 parts of 6mm basalt fiber.

The specific modification process of the fiber comprises the following steps:

2) soaking the uniformly mixed fibers in a sol solution, slowly heating to 73 ℃ at the speed of 2 ℃/min, carrying out heat preservation reaction for 3h, carrying out primary modification activation on the surfaces of the mixed fibers, and taking out for later use;

3) adding a modifier into the mixed fiber treated in the step 2), adding an ethanol solution, heating to 50 ℃ at the speed of 1.5 ℃/min, stirring while heating, carrying out heat preservation reaction for 5 hours, standing for 1d, and taking out for later use;

4) putting the mixed fiber prepared in the step 3) into 15% of water glass gel, putting the mixed fiber into a water bath kettle, heating the mixed fiber to 43 ℃ in a water bath, and carrying out heat preservation reaction for 5 hours to obtain the fiber.

The sol solution is a mixed solution prepared from 7% of NCC sol, 9% of polyvinylpyrrolidone hydrosol and 8% of chitosan hydrosol in a volume ratio of 4:3: 3.

The preparation of the modifier comprises the following steps:

a. adding 18 parts of sodium metaphosphate and 12 parts of dioctyl sodium sulfosuccinate into dichloromethane, heating to 130 ℃ at the speed of 4 ℃/min, and carrying out heat preservation reaction for 3 hours to obtain a reactant a;

b. adding 7 parts of tributyl phosphate and 1, 2-dichloromethane solvent into the reactant a, heating to 80 ℃ at the speed of 4 ℃/min, keeping the temperature, reacting for 5 hours, dropwise adding 12 parts of 1, 3-dicyclohexylcarbodiimide into the reactant a at the speed of 23 drops/min, stirring uniformly, slowly heating to 120 ℃ at the heating speed of 1.5 ℃/min, and keeping the temperature, reacting for 4 hours to obtain a reactant b;

c. adding 10 parts of sodium alcohol ether carboxylate into the reactant b, adding an acetone solvent, slowly heating to 130 ℃ at the speed of 2 ℃/for reacting for 4 hours in a heat preservation manner to obtain a reactant c;

d. and (3) adding 14 parts of guanylurea phosphate into the reactant c, adding a methanol solution, heating to 88 ℃ at the speed of 8 ℃/min, and carrying out heat preservation reaction for 5 hours to obtain the guanylurea phosphate.

The machine-made sand is mixed sand of 75 parts of 110-mesh quartz sand and 35 parts of 110-mesh modified plastic sand.

2) adding 10 parts of potassium oleate and 7 parts of 4-methyl-2-pentanol into ethanol solution, placing the mixture into a homogenization reaction kettle for homogenization treatment, placing the treated mixture into a reactor, slowly heating to 112 ℃ at the speed of 2 ℃/min, and carrying out heat preservation reaction for 3 hours to obtain an intermediate product i;

3) adding 14 parts of diethylamino methyl triethoxysilane into the intermediate product i, adding an ethyl acetate solvent, heating to 93 ℃ at the speed of 7 ℃/min, and carrying out heat preservation reaction for 4 hours to obtain an intermediate product ii;

4) adding 13 parts of chromium acetylacetonate and a toluene solution into the intermediate product ii, and putting the intermediate product ii into a high-pressure reaction kettle, wherein the pressure is 0.85Mpa, the temperature is 100 ℃, and the intermediate product iii is obtained after heat preservation reaction for 5 hours;

5) adding 18 parts of the plastic particle prepared in the step 1) into 6 parts of the intermediate product iii, adding N, N-dimethylformamide solution, uniformly stirring, adding 18 parts of microcrystalline paraffin, slowly heating to 45 ℃, and uniformly stirring to obtain the plastic particle.

Wherein the viscous solution is a mixed solution of 18% carboxymethyl cellulose solution and 9% calcium lignosulfonate solution in a volume ratio of 3: 2.

The preparation of the modified sealing agent comprises the following steps:

1) putting 14 parts of phenolic propane epoxy resin, 8 parts of cyanuric acid epoxy resin and 7 parts of resorcinol epoxy resin into a homogenization reaction kettle, adding ethyl acetate, carrying out homogenization treatment on the mixture, and pouring out the treated mixture for later use;

2) adding 8 parts of polycarbonate, 4 parts of polymethyl methacrylate and chloroform, slowly heating to 210 ℃ at the speed of 2 ℃/min, and carrying out heat preservation reaction for 8 hours to obtain a product a;

3) adding 7 parts of 4-methyl-2-pentanol and 11 parts of hexadecyl trimethoxy silane into the product a, adding toluene, heating to 120 ℃ at the speed of 6 ℃/min, and carrying out heat preservation reaction for 6 hours to obtain a product b;

4) adding 7 parts of disodium lauroamphodiacetate into the product b, adding a propanol solution into the product b, quickly heating to 150 ℃, and carrying out heat preservation reaction for 6 hours to obtain a product c;

5) and (3) adding the mixture prepared in the step (1) into the product c, mixing the mixture and the product c, pouring the mixture into a high-pressure reaction kettle, and keeping the temperature at 120 ℃ under the pressure of 0.9Mpa for reaction for 3 hours to obtain the product.

Example 2

An outer wall anti-cracking mortar comprises the following raw materials of P.O42.5 cement: 300 parts of machine-made sand: 650 parts of 325-mesh heavy calcium powder: 50 parts of cellulose ether: 3 parts of modified fiber: 5 parts of latex powder: 12 parts of modified sealing agent and 3 parts of modified sealing agent.

The modified fiber is as follows: the fiber is prepared by mixing and modifying 25 parts of polypropylene fiber, 30 parts of lignin fiber, 15 parts of steel nano fiber, 10 parts of brucite fiber, 15 parts of sepiolite fiber, 5 parts of 10mm carbon fiber and 8 parts of 6mm basalt fiber.

The specific modification process of the fiber comprises the following steps:

2) soaking the uniformly mixed fibers in a sol solution, slowly heating to 70 ℃ at the speed of 3 ℃/min, carrying out heat preservation reaction for 3h, carrying out primary modification activation on the surfaces of the mixed fibers, and taking out for later use;

3) adding a modifier into the mixed fiber treated in the step 2), adding an ethanol solution, heating to 50 ℃ at the speed of 2 ℃/min, stirring while heating, carrying out heat preservation reaction for 5 hours, standing for 1d, and taking out for later use;

4) putting the mixed fiber prepared in the step 3) into 15% of water glass gel, putting the mixed fiber into a water bath kettle, heating the mixed fiber to 40 ℃ in a water bath, and carrying out heat preservation reaction for 5 hours to obtain the fiber.

The sol solution is a mixed solution prepared from 8% of NCC sol, 7% of polyvinylpyrrolidone hydrosol and 10% of chitosan hydrosol in a volume ratio of 4:3: 3.

The preparation of the modifier comprises the following steps:

a. adding dichloromethane into 20 parts of sodium metaphosphate and 10 parts of dioctyl sodium sulfosuccinate, heating to 130 ℃ at the speed of 3 ℃/min, and carrying out heat preservation reaction for 3 hours to obtain a reactant a;

b. adding 5 parts of tributyl phosphate and 1, 2-dichloromethane solvent into the reactant a, heating to 80 ℃ at the speed of 5 ℃/min, keeping the temperature, reacting for 5 hours, dropwise adding 15 parts of 1, 3-dicyclohexylcarbodiimide into the reactant a at the speed of 20 drops/min, stirring uniformly, slowly heating to 120 ℃ at the heating speed of 1 ℃/min, and keeping the temperature, reacting for 4 hours to obtain a reactant b;

c. adding 12 parts of sodium alcohol ether carboxylate into the reactant b, adding an acetone solvent, slowly heating to 130 ℃ at the speed of 1 ℃/for reacting for 4 hours in a heat preservation manner to obtain a reactant c;

d. and (3) adding 15 parts of guanylurea phosphate into the reactant c, adding a methanol solution, heating to 90 ℃ at the speed of 7 ℃/min, and carrying out heat preservation reaction for 4 hours to obtain the guanylurea phosphate.

The machine-made sand is mixed sand of 70 parts of 100-mesh quartz sand and 40 parts of 120-mesh modified plastic sand.

2) adding 8 parts of potassium oleate and 9 parts of 4-methyl-2-pentanol into ethanol solution, placing the mixture into a homogenization reaction kettle for homogenization treatment, placing the treated mixture into a reactor, slowly heating to 120 ℃ at the speed of 1 ℃/min, and carrying out heat preservation reaction for 3 hours to obtain an intermediate product i;

3) adding 12 parts of diethylamino methyl triethoxysilane into the intermediate product i, adding an ethyl acetate solvent, heating to 90 ℃ at the speed of 8 ℃/min, and carrying out heat preservation reaction for 4 hours to obtain an intermediate product ii;

4) adding 12 parts of chromium acetylacetonate and a toluene solution into the intermediate product ii, and putting the intermediate product ii into a high-pressure reaction kettle, wherein the pressure is 0.9Mpa, the temperature is 95 ℃, and the intermediate product iii is obtained after heat preservation reaction for 5 hours;

5) adding 20 parts of the plastic particle prepared in the step 1) into 5 parts of the intermediate product iii, adding an N, N-dimethylformamide solution, uniformly stirring, adding 20 parts of microcrystalline paraffin, slowly heating to 45 ℃, and uniformly stirring to obtain the plastic particle.

Wherein the viscous solution is a mixed solution of 15% carboxymethyl cellulose solution and 10% calcium lignosulfonate solution in a volume ratio of 3: 2.

The preparation of the modified sealing agent comprises the following steps:

1) putting 12 parts of phenolic propane epoxy resin, 10 parts of cyanuric acid epoxy resin and 5 parts of resorcinol epoxy resin into a homogenization reaction kettle, adding ethyl acetate, carrying out homogenization treatment on the mixture, and pouring out the treated mixture for later use;

2) adding 10 parts of polycarbonate, 3 parts of polymethyl methacrylate and chloroform, slowly heating to 200 ℃ at the speed of 3 ℃/min, and carrying out heat preservation reaction for 8 hours to obtain a product a;

3) adding 8 parts of 4-methyl-2-pentanol and 7 parts of hexadecyl trimethoxy silane into the product a, adding toluene, heating to 120 ℃ at the speed of 7 ℃/min, and carrying out heat preservation reaction for 6 hours to obtain a product b;

4) adding 5 parts of disodium lauroamphodiacetate into the product b, adding a propanol solution into the product b, quickly heating to 150 ℃, and carrying out heat preservation reaction for 6 hours to obtain a product c;

5) and (3) adding the mixture prepared in the step (1) into the product c, mixing the mixture and the product c, pouring the mixture into a high-pressure reaction kettle, and keeping the temperature at 120 ℃ under the pressure of 1.0Mpa for reaction for 3 hours to obtain the product.

Example 3

An outer wall anti-cracking mortar comprises the following raw materials of P.O42.5 cement: 350 parts of machine-made sand: 650 parts of cellulose ether: 5 parts of modified fiber: 3 parts of latex powder: 18 parts of modified sealing agent and 1 part of modified sealing agent.

The modified fiber is as follows: 15 parts of polypropylene fiber, 35 parts of lignin fiber, 10 parts of steel nano fiber, 15 parts of brucite fiber, 10 parts of sepiolite fiber, 15 parts of 10mm carbon fiber and 5 parts of 6mm basalt fiber are mixed and modified to obtain the modified composite material.

The specific modification process of the fiber comprises the following steps:

2) soaking the uniformly mixed fibers in a sol solution, slowly heating to 75 ℃ at the speed of 1 ℃/min, carrying out heat preservation reaction for 3h, carrying out primary modification activation on the surfaces of the mixed fibers, and taking out for later use;

3) adding a modifier into the mixed fiber treated in the step 2), adding an ethanol solution, heating to 50 ℃ at the speed of 1 ℃/min, stirring while heating, carrying out heat preservation reaction for 5 hours, standing for 1d, and taking out for later use;

4) putting the mixed fiber prepared in the step 3) into 15% of water glass gel, putting the mixed fiber into a water bath kettle, heating the mixed fiber to 45 ℃ in a water bath, and carrying out heat preservation reaction for 5 hours to obtain the fiber.

The sol solution is a mixed solution prepared from 5% of NCC sol, 10% of polyvinylpyrrolidone hydrosol and 7% of chitosan hydrosol in a volume ratio of 4:3: 3.

The preparation of the modifier comprises the following steps:

a. adding dichloromethane into 15 parts of sodium metaphosphate and 13 parts of dioctyl sodium sulfosuccinate, heating to 130 ℃ at the speed of 5 ℃/min, and carrying out heat preservation reaction for 3 hours to obtain a reactant a;

b. adding 8 parts of tributyl phosphate and 1, 2-dichloromethane solvent into the reactant a, heating to 80 ℃ at the speed of 3 ℃/min, carrying out heat preservation reaction for 5 hours, dropwise adding 8 parts of 1, 3-dicyclohexylcarbodiimide into the reactant a at the speed of 25 drops/min, stirring uniformly, slowly heating to 120 ℃ at the heating speed of 2 ℃/min, and carrying out heat preservation reaction for 4 hours to obtain a reactant b;

c. adding 8 parts of sodium alcohol ether carboxylate into the reactant b, adding an acetone solvent, slowly heating to 130 ℃ at the speed of 3 ℃/for reacting for 4 hours in a heat preservation manner to obtain a reactant c;

d. and (3) adding 12 parts of guanylurea phosphate into the reactant c, adding a methanol solution, heating to 85-90 ℃ at the speed of 10 ℃/min, and carrying out heat preservation reaction for 6 hours to obtain the guanylurea phosphate.

The machine-made sand is mixed sand of 80 parts of 120-mesh quartz sand and 30 parts of 100-mesh modified plastic sand.

2) adding 12 parts of potassium oleate and 5 parts of 4-methyl-2-pentanol into ethanol solution, placing the mixture into a homogenization reaction kettle for homogenization treatment, placing the treated mixture into a reactor, slowly heating to 105 ℃ at the speed of 3 ℃/min, and carrying out heat preservation reaction for 3 hours to obtain an intermediate product i;

3) adding 15 parts of diethylamino methyl triethoxysilane into the intermediate product i, adding an ethyl acetate solvent, heating to 95 ℃ at the speed of 5 ℃/min, and carrying out heat preservation reaction for 4 hours to obtain an intermediate product ii;

4) adding 15 parts of chromium acetylacetonate and a toluene solution into the intermediate product ii, and putting the intermediate product ii into a high-pressure reaction kettle, wherein the pressure is 0.8Mpa, the temperature is 105 ℃, and the intermediate product iii is obtained after heat preservation reaction for 5 hours;

5) adding 15 parts of the plastic particle prepared in the step 1) into 7 parts of the intermediate product iii, adding an N, N-dimethylformamide solution, uniformly stirring, adding 15 parts of microcrystalline paraffin, slowly heating to 45 ℃, and uniformly stirring to obtain the plastic particle.

Wherein the viscous solution is a mixed solution of 20% carboxymethyl cellulose solution and 8% calcium lignosulfonate solution in a volume ratio of 3: 2.

The preparation of the modified sealing agent comprises the following steps:

1) placing 15 parts of phenolic propane epoxy resin, 5 parts of cyanuric acid epoxy resin and 8 parts of resorcinol epoxy resin into a homogenization reaction kettle, adding ethyl acetate, carrying out homogenization treatment on the mixture, and pouring out the treated mixture for later use;

2) adding 5 parts of polycarbonate, 5 parts of polymethyl methacrylate and trichloromethane, slowly heating to 220 ℃ at the speed of 1 ℃/min, and carrying out heat preservation reaction for 8 hours to obtain a product a;

3) adding 5 parts of 4-methyl-2-pentanol and 15 parts of hexadecyl trimethoxy silane into the product a, adding toluene, heating to 120 ℃ at the speed of 5 ℃/min, and carrying out heat preservation reaction for 6 hours to obtain a product b;

4) adding 8 parts of disodium lauroamphodiacetate into the product b, adding a propanol solution into the product b, quickly heating to 150 ℃, and carrying out heat preservation reaction for 6 hours to obtain a product c;

5) and (3) adding the mixture prepared in the step (1) into the product c, mixing the mixture and the product c, pouring the mixture into a high-pressure reaction kettle, and keeping the temperature at 120 ℃ under the pressure of 0.8Mpa for reaction for 3 hours to obtain the product.

Comparative example 1

An anti-crack mortar for external walls.

Wherein, the raw materials include P.O42.5 cement: 325 parts of machine-made sand: 700 parts of 325-mesh heavy calcium powder: 25 parts of cellulose ether: 4 parts of modified fiber: 4 parts of latex powder: 15 parts of modified sealing agent and 2 parts of modified sealing agent.

The rest is the same as example 1.

Comparative example 2

An anti-crack mortar for external walls.

Wherein, the raw materials include P.O42.5 cement: 325 parts of machine-made sand: 650 parts of 325-mesh heavy calcium powder: 25 parts of cellulose ether: 4 parts of modified fiber: 7 parts of latex powder: 15 parts of modified sealing agent and 2 parts of modified sealing agent.

The rest is the same as example 1.

Comparative example 3

An anti-crack mortar for external walls.

Wherein, the raw materials include P.O42.5 cement: 325 parts of machine-made sand: 650 parts of 325-mesh heavy calcium powder: 25 parts of cellulose ether: 4 parts of modified fiber: 4 parts of latex powder: 15 parts of modified sealing agent and 7 parts of modified sealing agent.

The rest is the same as example 1.

Comparative example 4

An anti-crack mortar for external walls.

Wherein the modified fiber is: the fiber is prepared by mixing and modifying 20 parts of polypropylene fiber, 33 parts of lignin fiber, 13 parts of steel nano fiber, 13 parts of brucite fiber, 8 parts of sepiolite fiber, 10 parts of 10mm carbon fiber and 7 parts of 6mm basalt fiber.

The rest is the same as example 1.

Comparative example 5

An anti-crack mortar for external walls.

Wherein the modified fiber is: the fiber is prepared by mixing and modifying 20 parts of polypropylene fiber, 33 parts of lignin fiber, 13 parts of steel nano fiber, 18 parts of brucite fiber, 13 parts of sepiolite fiber, 10 parts of 10mm carbon fiber and 7 parts of 6mm basalt fiber.

The rest is the same as example 1.

Comparative example 6

An anti-crack mortar for external walls.

Wherein the modified fiber is: the fiber is prepared by mixing and modifying 20 parts of polypropylene fiber, 25 parts of lignin fiber, 13 parts of steel nano fiber, 13 parts of brucite fiber, 13 parts of sepiolite fiber, 10 parts of 10mm carbon fiber and 7 parts of 6mm basalt fiber.

The rest is the same as example 1.

Comparative example 7

An anti-crack mortar for external walls.

The specific modification process of the fiber comprises the following steps:

2) soaking the uniformly mixed fibers in clear water, slowly heating to 73 ℃ at the speed of 2 ℃/min, carrying out heat preservation reaction for 3h, carrying out primary modification activation on the surfaces of the mixed fibers, and taking out for later use;

The rest is the same as example 1.

Comparative example 8

An anti-crack mortar for external walls.

The specific modification process of the fiber comprises the following steps:

2) soaking the uniformly mixed fibers in a sol solution, quickly heating to 73 ℃, carrying out heat preservation reaction for 3 hours, carrying out primary modification activation on the surfaces of the mixed fibers, and taking out for later use;

The rest is the same as example 1.

Comparative example 9

An anti-crack mortar for external walls.

The specific modification process of the fiber comprises the following steps:

3) adding a modifier into the mixed fiber treated in the step 2), adding an ethanol solution, heating to 50 ℃ at the speed of 1.5 ℃/min, stirring while heating, reacting for 5 hours in a heat preservation manner, and standing for 1d to obtain the composite fiber.

The rest is the same as example 1.

Comparative example 10

An anti-crack mortar for external walls.

The specific modification process of the fiber comprises the following steps:

3) adding the mixed fiber treated in the step 2) into an ethanol solution, heating to 50 ℃ at the speed of 1.5 ℃/min, stirring while heating, carrying out heat preservation reaction for 5 hours, standing for 1d, and taking out for later use;

The rest is the same as example 1.

Comparative example 11

An anti-crack mortar for external walls.

The specific modification process of the fiber comprises the following steps:

3) adding a modifier into the mixed fiber treated in the step 2), adding an ethanol solution, heating to 75 ℃ at the speed of 1.5 ℃/min, stirring while heating, carrying out heat preservation reaction for 5 hours, standing for 1d, and taking out for later use;

The rest is the same as example 1.

Comparative example 12

An anti-crack mortar for external walls.

The fibers are: 20 parts of polypropylene fiber, 33 parts of lignin fiber, 13 parts of steel nano fiber, 13 parts of brucite fiber, 13 parts of sepiolite fiber, 10 parts of 10mm carbon fiber and 7 parts of 6mm basalt fiber.

The rest is the same as example 1.

Comparative example 13

An anti-crack mortar for external walls.

The sol solution is a mixed solution prepared from 10% of NCC sol, 9% of polyvinylpyrrolidone hydrosol and 8% of chitosan hydrosol in a volume ratio of 4:3: 3.

The rest is the same as example 1.

Comparative example 14

An anti-crack mortar for external walls.

The sol solution is a mixed solution prepared from 7% of NCC sol, 5% of polyvinylpyrrolidone hydrosol and 8% of chitosan hydrosol in a volume ratio of 4:3: 3.

The rest is the same as example 1.

Comparative example 15

An anti-crack mortar for external walls.

The sol solution is a mixed solution prepared from 7% of NCC sol, 9% of polyvinylpyrrolidone hydrosol and 8% of chitosan hydrosol in a volume ratio of 4:3: 4.

The rest is the same as example 1.

Comparative example 16

An anti-crack mortar for external walls.

Wherein, the preparation of the modifier comprises the following steps:

a. adding 13 parts of sodium metaphosphate and 12 parts of dioctyl sodium sulfosuccinate into dichloromethane, heating to 130 ℃ at the speed of 4 ℃/min, and carrying out heat preservation reaction for 3 hours to obtain a reactant a;

The rest is the same as example 1.

Comparative example 17

An anti-crack mortar for external walls.

Wherein, the preparation of the modifier comprises the following steps:

a. adding 18 parts of sodium metaphosphate and 15 parts of dioctyl sodium sulfosuccinate into dichloromethane, heating to 130 ℃ at the speed of 4 ℃/min, and carrying out heat preservation reaction for 3 hours to obtain a reactant a;

The rest is the same as example 1.

Comparative example 18

An anti-crack mortar for external walls.

Wherein, the preparation of the modifier comprises the following steps:

b. adding 7 parts of tributyl phosphate and 1, 2-dichloromethane solvent into the reactant a, rapidly heating to 80 ℃, keeping the temperature and reacting for 5 hours, then dropwise adding 12 parts of 1, 3-dicyclohexylcarbodiimide into the reactant a at a rate of 23 drops/min, uniformly stirring, slowly heating to 120 ℃ at a heating rate of 1.5 ℃/min, keeping the temperature and reacting for 4 hours to obtain a reactant b;

The rest is the same as example 1.

Comparative example 19

An anti-crack mortar for external walls.

Wherein, the preparation of the modifier comprises the following steps:

b. adding 7 parts of tributyl phosphate, adding 1, 2-dichloromethane solvent and 12 parts of 1, 3-dicyclohexylcarbodiimide into the reactant a, heating to 120 ℃ at the speed of 4 ℃/min, and carrying out heat preservation reaction for 9 hours to obtain a reactant b;

The rest is the same as example 1.

Comparative example 20

An anti-crack mortar for external walls.

Wherein, the preparation of the modifier comprises the following steps:

c. adding 15 parts of sodium alcohol ether carboxylate into the reactant b, adding an acetone solvent, slowly heating to 130 ℃ at the speed of 2 ℃/for reacting for 4 hours in a heat preservation manner to obtain a reactant c;

The rest is the same as example 1.

Comparative example 21

An anti-crack mortar for external walls.

Wherein, the preparation of the modifier comprises the following steps:

c. adding 10 parts of sodium alcohol ether carboxylate into the reactant b, adding an acetone solvent, slowly heating to 100 ℃ at the speed of 2 ℃/for reacting for 4 hours in a heat preservation manner to obtain a reactant c;

The rest is the same as example 1.

Comparative example 22

An anti-crack mortar for external walls.

Wherein, the preparation of the modifier comprises the following steps:

d. adding 18 parts of guanylurea phosphate into the reactant c, adding a methanol solution, heating to 88 ℃ at the speed of 8 ℃/min, and carrying out heat preservation reaction for 5 hours to obtain the guanylurea phosphate.

The rest is the same as example 1.

Comparative example 23

An anti-crack mortar for external walls.

Wherein, the preparation of the modifier comprises the following steps:

d. and (3) adding 14 parts of guanylurea phosphate into the reactant c, adding a methanol solution, quickly heating to 88 ℃, and carrying out heat preservation reaction for 5 hours to obtain the guanylurea phosphate.

The rest is the same as example 1.

Comparative example 24

An anti-crack mortar for external walls.

Wherein the machine-made sand is mixed sand of 75 parts of 110-mesh quartz sand and 35 parts of 110-mesh plastic sand.

The rest is the same as example 1.

Comparative example 25

An anti-crack mortar for external walls.

Wherein the machine-made sand is mixed sand of 75 parts of 110-mesh quartz sand and 25 parts of 110-mesh modified plastic sand.

The rest is the same as example 1.

Comparative example 26

An anti-crack mortar for external walls.

1) putting the plastic particles into clear water, heating to 40 ℃, soaking for 6 hours, and taking out for later use;

The rest is the same as example 1.

Comparative example 27

An anti-crack mortar for external walls.

2) adding 15 parts of potassium oleate and 7 parts of 4-methyl-2-pentanol into ethanol solution, placing the mixture into a homogenization reaction kettle for homogenization treatment, placing the treated mixture into a reactor, slowly heating to 112 ℃ at the speed of 2 ℃/min, and carrying out heat preservation reaction for 3 hours to obtain an intermediate product i;

The rest is the same as example 1.

Comparative example 28

An anti-crack mortar for external walls.

2) putting 10 parts of potassium oleate and 7 parts of 4-methyl-2-pentanol into a reactor, slowly heating to 112 ℃ at the speed of 2 ℃/min, and reacting for 3 hours in a heat preservation manner to obtain an intermediate product i;

The rest is the same as example 1.

Comparative example 29

An anti-crack mortar for external walls.

2) adding 10 parts of potassium oleate and 7 parts of 4-methyl-2-pentanol into ethanol solution, placing the mixture into a homogenizing reaction kettle for homogenizing treatment, placing the treated mixture into a reactor, quickly heating to 112 ℃, and keeping the temperature for reaction for 3 hours to obtain an intermediate product i;

The rest is the same as example 1.

Comparative example 30

An anti-crack mortar for external walls.

3) adding 8 parts of diethylamino methyl triethoxysilane into the intermediate product i, adding an ethyl acetate solvent, heating to 93 ℃ at the speed of 7 ℃/min, and carrying out heat preservation reaction for 4 hours to obtain an intermediate product ii;

The rest is the same as example 1.

Comparative example 31

An anti-crack mortar for external walls.

4) adding 13 parts of chromium acetylacetonate and a toluene solution into the intermediate product ii, and putting the intermediate product ii into a high-pressure reaction kettle, wherein the pressure is 0.6Mpa, the temperature is 100 ℃, and the intermediate product iii is obtained after heat preservation reaction for 5 hours;

The rest is the same as example 1.

Comparative example 32

An anti-crack mortar for external walls.

5) adding 18 parts of the plastic particle prepared in the step 1) into 9 parts of the intermediate product iii, adding N, N-dimethylformamide solution, uniformly stirring, adding 18 parts of microcrystalline paraffin, slowly heating to 45 ℃, and uniformly stirring to obtain the plastic particle.

The rest is the same as example 1.

Comparative example 33

An anti-crack mortar for external walls.

Wherein the viscous solution is a mixed solution of 18% carboxymethyl cellulose solution and 9% calcium lignosulfonate solution in a volume ratio of 5: 3.

The rest is the same as example 1.

Comparative example 34

An anti-crack mortar for external walls.

Wherein the preparation of the modified sealing agent comprises the following steps:

1) putting 18 parts of phenolic propane epoxy resin, 8 parts of cyanuric acid epoxy resin and 7 parts of resorcinol epoxy resin into a homogenization reaction kettle, adding ethyl acetate, carrying out homogenization treatment on the mixture, and pouring out the treated mixture for later use;

The rest is the same as example 1.

Comparative example 35

An anti-crack mortar for external walls.

2) adding 12 parts of polycarbonate, 4 parts of polymethyl methacrylate and chloroform, slowly heating to 210 ℃ at the speed of 2 ℃/min, and carrying out heat preservation reaction for 8 hours to obtain a product a;

The rest is the same as example 1.

Comparative example 36

An anti-crack mortar for external walls.

2) adding 8 parts of polycarbonate, 4 parts of polymethyl methacrylate and chloroform, quickly heating to 210 ℃, and carrying out heat preservation reaction for 8 hours to obtain a product a;

The rest is the same as example 1.

Comparative example 37

An anti-crack mortar for external walls.

3) adding 7 parts of 4-methyl-2-pentanol and 18 parts of hexadecyl trimethoxy silane into the product a, adding toluene, heating to 120 ℃ at the speed of 6 ℃/min, and carrying out heat preservation reaction for 6 hours to obtain a product b;

The rest is the same as example 1.

Comparative example 38

An anti-crack mortar for external walls.

4) adding 10 parts of disodium lauroamphodiacetate into the product b, adding a propanol solution into the product b, quickly heating to 150 ℃, and carrying out heat preservation reaction for 6 hours to obtain a product c;

The rest is the same as example 1.

Comparative example 39

An anti-crack mortar for external walls.

5) and (3) adding the mixture prepared in the step (1) into the product c, mixing the mixture and the product c, pouring the mixture into a high-pressure reaction kettle, and keeping the temperature at 110 ℃ under the pressure of 0.9Mpa for reaction for 3 hours to obtain the product.

The rest is the same as example 1.

Comparative example 40

An anti-crack mortar for external walls.

The sealing agent is a common curing agent and has the model of SDP-700D.

The rest is the same as example 1.

Comparative example 41

The anti-crack mortar is common outer wall anti-crack mortar.

Experimental example 1 anti-crack effect of mortar

Coating the mortar prepared in the embodiment and the comparative example on a test wall according to a general construction process and maintenance conditions, observing the surface crack condition of the mortar after 28 days, and testing the crack between the mortar and a substrate layer by adopting ultrasonic waves, wherein the specific evaluation standard is shown in table 1, and the evaluation result is recorded in table 2;

TABLE 1 evaluation of the integrity of the mortars

TABLE 2 gap inside mortar

As can be seen from Table 2, the crack resistance of the crack resistant mortar prepared in examples 1-3 was tested to be much better than that of the conventional crack resistant mortar for exterior walls in comparative example 41. The comparative examples 1 to 3 change the formula proportion of the external wall anti-cracking mortar, so the anti-cracking evaluation of the mortar is reduced; comparative examples 4-6 varying the proportion of fibers results in a decrease in the cohesion of the mortar and therefore a decrease in the crack resistance of the mortar. Comparative examples 7 to 11 changed the process of modifying the fibers, so that the mortar was not evaluated for crack resistance as in examples 1 to 3, and even some of the mortar prepared by the method had more cracks than the ordinary crack resistant mortar of comparative example 41; comparative example 12 ordinary unmodified fibers were added to the mortar, causing the fibers to agglomerate in the presence of the modified plastic sand and the modified potting agent, reducing the adhesion between the mortar and the substrate, and allowing the mortar to fall off. Comparative examples 16 to 23 are directed to the changes in the preparation process and formulation of the modifier, which in turn resulted in the changes in the components of the modifier, so that the fibers could not be effectively modified and the crack resistance of the mortar decreased. Comparative examples 25 to 33 changed the preparation process and the related formulation for preparing the modified plastic sand, resulting in the modification effect of the plastic sand being lower than that of examples 1 to 3 and the crack resistance of the mortar being lower than that of examples 1 to 3 comparative example 24 is an unmodified plastic sand which is easily agglomerated with the fibers in the overall mortar environment, resulting in the failure of the fibers to exert the crack resistance. The comparative examples 34 to 39 change the formula and the process of the sealing agent, so that the molecular structure of the modified sealing agent is changed, and the anti-cracking effect of the mortar is reduced. Comparative example 40 is a common curing agent, but the curing agent cannot effectively exert the effect of sealing and curing, but is easily intertwined with the modified plastic sand and the fibers, so the crack resistance evaluation of the mortar is even lower than that of comparative example 41.

Experimental example 2 thermal conductivity of mortar

The mortar prepared in the embodiment and the comparative example is coated on an outer wall according to a general construction method, the thermal conductivity coefficient of the mortar is tested according to the industrial standard JGJ144-2019 technical Standard for external thermal insulation engineering of outer wall, and the specific data are recorded in Table 3; the thermal conductivity of the insulation board is 0.042W/(m.K), so the thermal conductivity of the mortar is closer to that of the insulation board, and the performance of the mortar is better;

TABLE 3 thermal conductivity of the mortars

From the data in table 3, the thermal conductivity of examples 1-3 is closer to that of the insulation board than the other comparative examples, so the crack resistance effect of the mortar is effectively reduced. However, in the comparative example 12, ordinary fibers are selected for mixing, and since the diameter of the fibers is nano-scale, the unmodified fibers are easy to agglomerate in the mortar, so that the uniformity of the mortar is poor, and the heat conductivity coefficient is also large. The comparative example 24 adopts common plastic sand, and the comparative example 40 adopts common curing agent, but the plastic sand and the curing agent can not be effectively matched with other components in the mortar, so that the thermal conductivity of the mortar is higher. Comparative example 25 the proportion of modified plastic sand in the machine-made sand was reduced, resulting in a decrease in the thermal conductivity of the mortar. The formulas of the preparation processes of the modified plastic sand are changed in the comparative examples 27, 30 and 32-33, so that the modification effect of the modified plastic sand is reduced, the modified plastic sand cannot be connected with other components in the mortar to form a whole, the thermal conductivity of the mortar is higher than that of the preparation processes of the modified plastic sand in the examples 1-3, 26, 28-29 and 31, the effective modified components on the surface of the modified plastic sand are reduced, and the thermal conductivity of the mortar is only 0.521W/(m.K) at the lowest.

Experimental example 3 mortar flatness

Testing the flatness of the ground after mortar is solidified according to the requirement on the flatness of the wall surface in the national standard GB50210-2018 acceptance Standard for construction quality of architectural decoration and finishing engineering, wherein the standard requires that the allowable deviation of the flatness of the plastering surface of the cement mortar ground is 4 mm; after the mortars prepared in the examples and the comparative examples are well maintained, the flatness of the mortars is tested, and the specific data results are recorded in a table 4;

TABLE 4 mortar flatness deviation

As can be seen from Table 4, the flatness deviation of examples 1 to 3 was only 0.09 to 0.11mm, and the flatness deviation was much lower than that of comparative example 41. Comparative example 25 the proportion of modified plastic sand in the machine-made sand was reduced, resulting in a decrease in the overall mix of the mortar, so the mortar had a much higher deviation in flatness than examples 1-3. Comparative example 12 common fibers were selected for mixing, and since the fibers had too small a diameter, they were very likely to agglomerate in the mortar, resulting in poor uniformity of the mortar, and the mortar was very uneven. The comparative example 24 adopts common plastic sand, and the comparative example 40 adopts common curing agent, but the common plastic sand and the common curing agent can not be effectively matched with other components in the mortar, and can easily react with other modified components under the high-temperature environment, so that the flatness deviation of the mortar is not in line with the standard.

Comparative examples 26-33 were modified for the formulation and process of the modified plastic sand. Wherein, the comparative examples 26, 28 to 29 and 31 change the preparation process of the modified plastic sand, and the comparative examples 27, 30 and 32 to 33 change the formula of the preparation process of the modified plastic sand, which all reduce the modification effect of the modified plastic sand, lead to the reduction of the bonding capability of the modified plastic sand, and the deviation of the flatness of the mortar is only 2.15mm at least.

Comparative examples 34-39 were modified for the formulation and process of the modified sealer. Wherein, the formulas of the modified sealing agents are changed in comparative examples 34 to 35 and 37 to 38, and the preparation process of the modified sealing agent is changed in comparative examples 36 and 39, which all result in the components and the structure of the modified sealing agent, so that the flatness deviation of the mortar is between 2.18 and 3.27 mm.

Claims

1. The external wall anti-cracking mortar is characterized in that: the raw materials comprise P.O42.5 cement: 300-350 parts of machine-made sand: 650 parts of 325-mesh heavy calcium powder: 0-50 parts of cellulose ether: 3-5 parts of modified fiber: 3-5 parts of latex powder: 12-18 parts of modified sealing agent and 1-3 parts of modified sealing agent.

2. The exterior wall anti-crack mortar of claim 1, wherein: the modified fiber is as follows: 15-25 parts of polypropylene fiber, 30-35 parts of lignin fiber, 10-15 parts of steel nano fiber, 10-15 parts of brucite fiber, 10-15 parts of sepiolite fiber, 5-15 parts of 10mm carbon fiber and 5-8 parts of 6mm basalt fiber are mixed and modified to obtain the composite fiber.

3. The exterior wall anti-crack mortar of claim 2, wherein: the specific modification process of the fiber comprises the following steps:

4. The exterior wall anti-crack mortar of claim 3, wherein: the sol solution is a mixed solution prepared from 5-8% of NCC sol, 7-10% of polyvinylpyrrolidone hydrosol and 7-10% of chitosan hydrosol according to the volume ratio of 4:3: 3.

5. The exterior wall anti-crack mortar of claim 3, wherein: the preparation of the modifier is as follows:

6. The exterior wall anti-crack mortar of claim 1, wherein: the mechanism sand is mixed sand of 70-80 parts of 100-sand 120-mesh quartz sand and 30-40 parts of 100-sand 120-mesh modified plastic sand.

7. The exterior wall anti-crack mortar of claim 6, wherein: the modified plastic sand is prepared as follows:

8. The exterior wall anti-crack mortar of claim 6, wherein: the viscous solution is a mixed solution of 15-20% of carboxymethyl cellulose solution and 8-10% of calcium lignosulfonate solution in a volume ratio of 3: 2.

9. The exterior wall anti-crack mortar of claim 1, wherein: the preparation of the modified sealing agent comprises the following steps: