A road epoxy asphalt toughening additive and preparation method thereof

Abstract

The invention belongs to the field of roads, and specifically relates to a road epoxy asphalt toughening additive and a preparation method thereof, wherein calcium carbonate whiskers are prepared from calcium 2-methoxyethoxide and ammonium bicarbonate, and the calcium carbonate whiskers are hydrophobically modified to obtain modified calcium carbonate; calcium sulfate is surface coated, and then the coated calcium sulfate and the modified calcium carbonate are mixed, and the two are placed together in an ethanol dispersion of ammonium carbonate, and fully dispersed to obtain a road epoxy asphalt toughening additive. The road epoxy asphalt toughening additive of the present invention can directionally fill the pores of the road system during subsequent road use, bridge and repair the cracks, make the internal structure more compact, achieve continuous toughening, and improve the durability and service life of the road.

Description

Technical Field

[0001] The invention belongs to the field of roads, and in particular relates to a road epoxy asphalt toughening additive and a preparation method thereof. Background Art

[0002] Asphalt pavement is widely used in highways of all grades because of its smooth surface, good driving comfort, low noise from vehicle driving, easy construction, paving and later maintenance. However, ordinary asphalt pavement is easily affected by adverse environmental conditions such as temperature, precipitation and traffic volume changes during use. Ordinary asphalt pavement with poor durability is prone to asphalt pavement diseases such as rutting, cracking, peeling, surface polishing, frost heave and slurrying. The thermosetting characteristics of epoxy asphalt can improve the road's resistance to temperature changes and extend its life. It has been deeply developed and utilized, but it cannot significantly improve the damage caused by other factors to asphalt pavement. Whiskers are usually used as an important reinforcing material due to their high aspect ratio, high strength and tensile properties. They are added to flame retardant materials, building materials, composite materials and friction materials. The mechanism of action of whiskers in composite materials is mainly reflected in four aspects: load transfer, crack bridging, crack deflection and pull-out effect. Inorganic salt whiskers have high strength and modulus, so the performance quality of epoxy asphalt can be improved by adding inorganic salt whiskers, which can enhance and toughen epoxy asphalt. However, most inorganic salt whiskers have certain acidity and alkalinity, have hydrophilic groups on their surface, and are polar, which can easily absorb moisture, while epoxy asphalt is hydrophobic, and the interfacial bonding ability of the two is poor. Directly adding inorganic salt whiskers to epoxy asphalt will make it difficult for the two to form a good bond, which can easily lead to uneven dispersion of whiskers in the matrix, and even if inorganic salt whiskers are added, they can generally only play an incremental role in the matrix. Summary of the invention

[0003] The present invention mainly provides an epoxy asphalt toughening additive for roads that has good affinity with epoxy asphalt, can continuously increase the toughness of epoxy asphalt roads, and repair cracks, as well as a preparation method and application of the additive. The technical scheme is as follows:

[0004] A method for preparing a toughening additive for epoxy asphalt of a road comprises the following steps: preparing calcium carbonate whiskers using calcium 2-methoxyethoxide and ammonium bicarbonate, and hydrophobically modifying the calcium carbonate whiskers to obtain modified calcium carbonate; surface coating calcium sulfate, and then mixing the coated calcium sulfate and the modified calcium carbonate, placing the mixture together in an ethanol dispersion of ammonium carbonate, and fully dispersing the mixture to obtain the toughening additive for epoxy asphalt of a road.

[0005] Furthermore, the mass ratio of the calcium 2-methoxyethanol to ammonium bicarbonate is 1:1.5-5; the mass ratio of the modified calcium carbonate to the coated calcium sulfate is 1:0.2-0.8; the mass ratio of the coated calcium sulfate to ammonium carbonate is 1:2-4; and the concentration of ammonium carbonate in the ethanol dispersion of ammonium carbonate is 4-10 g / L.

[0006] Furthermore, the preparation of the modified calcium carbonate comprises the following steps:

[0007] a. Place calcium 2-methoxyethoxide in ethanol and fully disperse it to obtain a calcium 2-methoxyethoxide dispersion; dissolve cyclodextrin in the calcium 2-methoxyethoxide dispersion to obtain a precursor liquid; prepare an ammonium bicarbonate solution by taking ammonium bicarbonate, and slowly drop the ammonium bicarbonate solution into the precursor liquid. After the dropwise addition is completed, seal the container, heat it to 35-50°C, stir it at a low speed to react for 0.5-2h, cool it naturally and let it stand for 10-20h to obtain a reaction liquid containing calcium carbonate whiskers;

[0008] b. Use calcium hydroxide to adjust the pH value of the reaction solution containing calcium carbonate whiskers to 8-10, then add calcium chloroacetate, react at 60-70°C for 2-3 hours, remove the solvent by rotary evaporation, then rinse with water until the pH of the washing solution is neutral, and dry to obtain modified calcium carbonate.

[0009] Furthermore, the speed of the slow dripping is 0.05-0.2 mL / s; and the speed of the low-speed stirring is 100-250 rpm.

[0010] Furthermore, the mass ratio of the cyclodextrin to calcium 2-methoxyethanol is 1:5-8; the mass ratio of the calcium chloroacetate to the cyclodextrin is 1.2-2.8:1.

[0011] Further, the surface coating of calcium sulfate comprises the following steps:

[0012] Mix calcium sulfate with a small amount of ammonium carbonate, place in water to fully disperse, then add cyclodextrin, evaporate the solvent with stirring at 25-40°C to a solid content of 50-75%, raise the temperature to 60-75°C, and continue evaporating until the weight no longer changes, thus completing the surface coating.

[0013] Furthermore, the cyclodextrin is β-cyclodextrin.

[0014] Furthermore, the mass ratio of the calcium sulfate to a small amount of ammonium carbonate is 15-25:1; the mass ratio of the calcium sulfate to cyclodextrin is 2.5-4:1.

[0015] The epoxy asphalt toughening additive for roads prepared by the above method is added in an amount of 0.2-2% in road mineral materials.

[0016] An application of the road epoxy asphalt toughening additive prepared by the above method in road construction is to mix the mineral materials and additives used for paving with epoxy asphalt to obtain a base to be poured; before paving, the road epoxy asphalt toughening additive is added to the base to be poured, and the mixture is fully stirred to obtain a casting material, and the casting material is poured to the target position and then paving construction is carried out.

[0017] By adopting the above scheme, the method of the present invention has the following advantages:

[0018] 1. The toughening agent of the present invention can achieve toughening of the road after the road construction is completed, and in the subsequent use of the road, the calcium carbonate whiskers can continue to grow spontaneously, directionally fill the pores of the road system, bridge and repair the cracks, make the internal structure denser, achieve continuous toughening, and improve the durability and service life of the road.

[0019] 2. The present invention provides a carbon dioxide atmosphere through the natural decomposition of ammonium carbonate, and generates calcium carbonate whiskers at a relatively slow rate together with the slowly decomposed calcium 2-methoxyethanol, so that the whiskers are more completely generated and have a larger aspect ratio, thereby avoiding the rapid and violent reaction that affects the growth of the whiskers.

[0020] 3. When modifying calcium carbonate, the present invention directly etherifies the cyclodextrin used for whisker growth to improve hydrophobicity and increase the interface bonding ability between the whiskers and the matrix. Then, by rotary evaporation, the etherified cyclodextrin is more firmly connected to the calcium carbonate whiskers, thereby achieving the modification of the calcium carbonate whiskers.

[0021] 4. The modification of calcium carbonate in the present invention is directly carried out in succession with the preparation, and less raw materials are used, thus avoiding the waste of raw materials during filtration and washing, saving raw materials and preparation costs, improving the integration of the preparation scheme, and facilitating industrial applications.

[0022] 5. The present invention not only provides filler and toughening properties of calcium sulfate, but also utilizes the low solubility of calcium sulfate to achieve the slow release of calcium ions on the basis of coating the calcium sulfate, thereby providing raw materials for the continued growth of calcium carbonate whiskers. After the road has been in service for a long time and has suffered more damage, the coating ability of the cyclodextrin coating layer gradually weakens under the influence of the environment and microorganisms, which will expose more calcium sulfate, increase the growth rate of the calcium carbonate whiskers, achieve continuous toughening and repair of the road epoxy asphalt, and improve the service life of the road.

[0023] 6. The present invention coats calcium carbonate that is easily decomposed into gas together with calcium sulfate. In the later stage of coating, the temperature is raised to allow the gas to overflow, causing holes to appear in the coating layer, which facilitates the ionization of calcium in the calcium sulfate and realizes the controlled release of calcium ions.

[0024] 7. The additive of the present invention is easy to use and does not require special conditions, methods or equipment. It can be used in ordinary road paving construction processes. It is easy to operate and has a low threshold for use and application. Calcium carbonate whiskers are cheap and easy to obtain. Even if you do not prepare them yourself, you can directly purchase them and then modify them. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Example 1: (1) 2 g of calcium 2-methoxyethanolate was placed in ethanol and fully dispersed to obtain a calcium 2-methoxyethanolate dispersion; 0.25 g of β-cyclodextrin was dissolved in the calcium 2-methoxyethanolate dispersion to obtain a precursor liquid; 5 g of ammonium bicarbonate was taken to prepare an ammonium bicarbonate solution, and the ammonium bicarbonate solution was slowly added to the precursor liquid at a rate of 0.1 mL / s. After the addition was completed, the container was closed, the temperature was raised to 35°C, and the reaction was stirred at a low speed of 100 rpm for 0.5 h. After the temperature was naturally lowered and the reaction mixture was allowed to stand for 10 h, a reaction liquid containing calcium carbonate whiskers was obtained;

[0027] (2) Using calcium hydroxide to adjust the pH value of the reaction solution containing calcium carbonate whiskers to 9, then adding 0.3 g of calcium chloroacetate, reacting at 60° C. for 2 to 3 hours, rotary evaporating to remove the solvent, then washing with water until the pH of the washing solution is neutral, and drying to obtain modified calcium carbonate;

[0028] (3) Mix 3g of calcium sulfate and 0.2g of ammonium carbonate, place them in water and fully disperse them, then add 1g of β-cyclodextrin, stir and evaporate the solvent at 25°C until the solid content is 50%, raise the temperature to 60-75°C, and continue to evaporate until the weight no longer changes, thus completing the surface coating;

[0029] (4) 4 g of ammonium carbonate was dispersed in ethanol to obtain a 7 g / L ammonium carbonate ethanol dispersion; 2 g of the coated calcium sulfate was mixed with 2.5 g of modified calcium carbonate, and the mixture was placed in the ethanol dispersion containing ammonium carbonate and fully dispersed to obtain a road epoxy asphalt toughening additive.

[0030] Example 2: (1) 2 g of calcium 2-methoxyethanolate was placed in ethanol and fully dispersed to obtain a calcium 2-methoxyethanolate dispersion; 0.4 g of β-cyclodextrin was dissolved in the calcium 2-methoxyethanolate dispersion to obtain a precursor liquid; 5 g of ammonium bicarbonate was taken to prepare an ammonium bicarbonate solution, and the ammonium bicarbonate solution was slowly added to the precursor liquid at a rate of 0.1 mL / s. After the addition was completed, the container was closed, the temperature was raised to 35°C, and the reaction was stirred at a low speed of 100 rpm for 0.5 h. After the temperature was naturally lowered and the reaction mixture was allowed to stand for 10 h, a reaction liquid containing calcium carbonate whiskers was obtained;

[0031] (2) Using calcium hydroxide to adjust the pH value of the reaction solution containing calcium carbonate whiskers to 9, then adding 0.5 g of calcium chloroacetate, reacting at 60° C. for 2 to 3 hours, removing the solvent by rotary evaporation, then washing with water until the pH of the washing solution is neutral, and drying to obtain modified calcium carbonate;

[0032] (3) Mix 3g of calcium sulfate and 0.2g of ammonium carbonate, place them in water and fully disperse them, then add 1g of β-cyclodextrin, stir and evaporate the solvent at 25°C until the solid content is 50%, raise the temperature to 60-75°C, and continue to evaporate until the weight no longer changes, thus completing the surface coating;

[0033] (4) 4 g of ammonium carbonate was dispersed in ethanol to obtain a 7 g / L ammonium carbonate ethanol dispersion; 2 g of the coated calcium sulfate was mixed with 2.5 g of modified calcium carbonate, and the mixture was placed in the ethanol dispersion containing ammonium carbonate and fully dispersed to obtain a road epoxy asphalt toughening additive.

[0034] Example 3: (1) 2 g of calcium 2-methoxyethanolate was placed in ethanol and fully dispersed to obtain a calcium 2-methoxyethanolate dispersion; 0.25 g of β-cyclodextrin was dissolved in the calcium 2-methoxyethanolate dispersion to obtain a precursor liquid; 5 g of ammonium bicarbonate was taken to prepare an ammonium bicarbonate solution, and the ammonium bicarbonate solution was slowly added to the precursor liquid at a rate of 0.1 mL / s. After the addition was completed, the container was closed, the temperature was raised to 50°C, and the reaction was stirred at a low speed of 100 rpm for 0.5 h. After the temperature was naturally lowered and the reaction mixture was allowed to stand for 10 h, a reaction liquid containing calcium carbonate whiskers was obtained;

[0035] (2) Using calcium hydroxide to adjust the pH value of the reaction solution containing calcium carbonate whiskers to 9, then adding 0.3 g of calcium chloroacetate, reacting at 60° C. for 2 to 3 hours, rotary evaporating to remove the solvent, then washing with water until the pH of the washing solution is neutral, and drying to obtain modified calcium carbonate;

[0036] (3) Mix 3g of calcium sulfate and 0.2g of ammonium carbonate, place them in water and fully disperse them, then add 1g of β-cyclodextrin, stir and evaporate the solvent at 25°C until the solid content is 50%, raise the temperature to 60-75°C, and continue to evaporate until the weight no longer changes, thus completing the surface coating;

[0037] (4) 4 g of ammonium carbonate was dispersed in ethanol to obtain a 7 g / L ammonium carbonate ethanol dispersion; 2 g of the coated calcium sulfate was mixed with 2.5 g of modified calcium carbonate, and the mixture was placed in the ethanol dispersion containing ammonium carbonate and fully dispersed to obtain a road epoxy asphalt toughening additive.

[0038] Example 4: (1) 2 g of calcium 2-methoxyethanolate was placed in ethanol and fully dispersed to obtain a calcium 2-methoxyethanolate dispersion; 0.25 g of β-cyclodextrin was dissolved in the calcium 2-methoxyethanolate dispersion to obtain a precursor liquid; 5 g of ammonium bicarbonate was taken to prepare an ammonium bicarbonate solution, and the ammonium bicarbonate solution was slowly added to the precursor liquid at a rate of 0.1 mL / s. After the addition was completed, the container was closed, the temperature was raised to 35°C, and the reaction was stirred at a low speed of 250 rpm for 0.5 h. After the temperature was naturally lowered and the mixture was allowed to stand for 10 h, a reaction liquid containing calcium carbonate whiskers was obtained;

[0039] (2) Using calcium hydroxide to adjust the pH value of the reaction solution containing calcium carbonate whiskers to 9, then adding 0.3 g of calcium chloroacetate, reacting at 60° C. for 2 to 3 hours, rotary evaporating to remove the solvent, then washing with water until the pH of the washing solution is neutral, and drying to obtain modified calcium carbonate;

[0040] (3) Mix 3g of calcium sulfate and 0.2g of ammonium carbonate, place them in water and fully disperse them, then add 1g of β-cyclodextrin, stir and evaporate the solvent at 25°C until the solid content is 50%, raise the temperature to 60-75°C, and continue to evaporate until the weight no longer changes, thus completing the surface coating;

[0041] (4) 4 g of ammonium carbonate was dispersed in ethanol to obtain a 7 g / L ammonium carbonate ethanol dispersion; 2 g of the coated calcium sulfate was mixed with 2.5 g of modified calcium carbonate, and the mixture was placed in the ethanol dispersion containing ammonium carbonate and fully dispersed to obtain a road epoxy asphalt toughening additive.

[0042] Example 5: (1) 2 g of calcium 2-methoxyethanolate was placed in ethanol and fully dispersed to obtain a calcium 2-methoxyethanolate dispersion; 0.25 g of β-cyclodextrin was dissolved in the calcium 2-methoxyethanolate dispersion to obtain a precursor liquid; 5 g of ammonium bicarbonate was taken to prepare an ammonium bicarbonate solution, and the ammonium bicarbonate solution was slowly added to the precursor liquid at a rate of 0.1 mL / s. After the addition was completed, the container was closed, the temperature was raised to 35°C, and the reaction was stirred at a low speed of 100 rpm for 2 hours. After the temperature was naturally lowered and the reaction was allowed to stand for 10 hours, a reaction liquid containing calcium carbonate whiskers was obtained;

[0043] (2) Using calcium hydroxide to adjust the pH value of the reaction solution containing calcium carbonate whiskers to 9, then adding 0.3 g of calcium chloroacetate, reacting at 60° C. for 2 to 3 hours, rotary evaporating to remove the solvent, then washing with water until the pH of the washing solution is neutral, and drying to obtain modified calcium carbonate;

[0044] (3) Mix 3g of calcium sulfate and 0.2g of ammonium carbonate, place them in water and fully disperse them, then add 1g of β-cyclodextrin, stir and evaporate the solvent at 25°C until the solid content is 50%, raise the temperature to 60-75°C, and continue to evaporate until the weight no longer changes, thus completing the surface coating;

[0045] (4) 4 g of ammonium carbonate was dispersed in ethanol to obtain a 7 g / L ammonium carbonate ethanol dispersion; 2 g of the coated calcium sulfate was mixed with 2.5 g of modified calcium carbonate, and the mixture was placed in the ethanol dispersion containing ammonium carbonate and fully dispersed to obtain a road epoxy asphalt toughening additive.

[0046] Example 6: (1) 2 g of calcium 2-methoxyethanolate was placed in ethanol and fully dispersed to obtain a calcium 2-methoxyethanolate dispersion; 0.25 g of β-cyclodextrin was dissolved in the calcium 2-methoxyethanolate dispersion to obtain a precursor liquid; 5 g of ammonium bicarbonate was taken to prepare an ammonium bicarbonate solution, and the ammonium bicarbonate solution was slowly added to the precursor liquid at a rate of 0.1 mL / s. After the addition was completed, the container was closed, the temperature was raised to 35°C, and the reaction was stirred at a low speed of 100 rpm for 0.5 h. After the temperature was naturally lowered and allowed to stand for 20 h, a reaction liquid containing calcium carbonate whiskers was obtained;

[0047] (2) Using calcium hydroxide to adjust the pH value of the reaction solution containing calcium carbonate whiskers to 9, then adding 0.3 g of calcium chloroacetate, reacting at 60° C. for 2 to 3 hours, rotary evaporating to remove the solvent, then washing with water until the pH of the washing solution is neutral, and drying to obtain modified calcium carbonate;

[0048] (3) Mix 3g of calcium sulfate and 0.2g of ammonium carbonate, place them in water and fully disperse them, then add 1g of β-cyclodextrin, stir and evaporate the solvent at 25°C until the solid content is 50%, raise the temperature to 60-75°C, and continue to evaporate until the weight no longer changes, thus completing the surface coating;

[0049] (4) 4 g of ammonium carbonate was dispersed in ethanol to obtain a 7 g / L ammonium carbonate ethanol dispersion; 2 g of the coated calcium sulfate was mixed with 2.5 g of modified calcium carbonate, and the mixture was placed in the ethanol dispersion containing ammonium carbonate and fully dispersed to obtain a road epoxy asphalt toughening additive.

[0050] Example 7: (1) 2 g of calcium 2-methoxyethanolate was placed in ethanol and fully dispersed to obtain a calcium 2-methoxyethanolate dispersion; 0.25 g of β-cyclodextrin was dissolved in the calcium 2-methoxyethanolate dispersion to obtain a precursor liquid; 5 g of ammonium bicarbonate was taken to prepare an ammonium bicarbonate solution, and the ammonium bicarbonate solution was slowly added to the precursor liquid at a rate of 0.1 mL / s. After the addition was completed, the container was closed, the temperature was raised to 35°C, and the reaction was stirred at a low speed of 100 rpm for 0.5 h. After the temperature was naturally lowered and allowed to stand for 10 h, a reaction liquid containing calcium carbonate whiskers was obtained;

[0051] (2) Using calcium hydroxide to adjust the pH value of the reaction solution containing calcium carbonate whiskers to 9, then adding 1 g of calcium chloroacetate, reacting at 60°C for 2-3 hours, removing the solvent by rotary evaporation, then washing with water until the pH of the washing solution is neutral, and drying to obtain modified calcium carbonate;

[0052] (3) Mix 3g of calcium sulfate and 0.2g of ammonium carbonate, place them in water and fully disperse them, then add 1g of β-cyclodextrin, stir and evaporate the solvent at 25°C until the solid content is 50%, raise the temperature to 60-75°C, and continue to evaporate until the weight no longer changes, thus completing the surface coating;

[0053] (4) 4 g of ammonium carbonate was dispersed in ethanol to obtain a 7 g / L ammonium carbonate ethanol dispersion; 2 g of the coated calcium sulfate was mixed with 2.5 g of modified calcium carbonate, and the mixture was placed in the ethanol dispersion containing ammonium carbonate and fully dispersed to obtain a road epoxy asphalt toughening additive.

[0054] Example 8: (1) 2 g of calcium 2-methoxyethanolate was placed in ethanol and fully dispersed to obtain a calcium 2-methoxyethanolate dispersion; 0.25 g of β-cyclodextrin was dissolved in the calcium 2-methoxyethanolate dispersion to obtain a precursor liquid; 5 g of ammonium bicarbonate was taken to prepare an ammonium bicarbonate solution, and the ammonium bicarbonate solution was slowly added to the precursor liquid at a rate of 0.1 mL / s. After the addition was completed, the container was sealed, the temperature was raised to 35°C, and the reaction was stirred at a low speed of 100 rpm for 0.5 h. After the temperature was naturally lowered and allowed to stand for 10 h, a reaction liquid containing calcium carbonate whiskers was obtained;

[0055] (2) Using calcium hydroxide to adjust the pH value of the reaction solution containing calcium carbonate whiskers to 9, then adding 0.3 g of calcium chloroacetate, reacting at 60° C. for 2 to 3 hours, rotary evaporating to remove the solvent, then washing with water until the pH of the washing solution is neutral, and drying to obtain modified calcium carbonate;

[0056] (3) Mix 5g of calcium sulfate and 0.2g of ammonium carbonate, place them in water and fully disperse them, then add 1.5g of β-cyclodextrin, stir and evaporate the solvent at 25°C until the solid content is 50%, raise the temperature to 60-75°C, and continue to evaporate until the weight no longer changes, thus completing the surface coating;

[0057] (4) 4 g of ammonium carbonate was dispersed in ethanol to obtain a 7 g / L ammonium carbonate ethanol dispersion; 2 g of the coated calcium sulfate was mixed with 2.5 g of modified calcium carbonate, and the mixture was placed in the ethanol dispersion containing ammonium carbonate and fully dispersed to obtain a road epoxy asphalt toughening additive.

[0058] Example 9: (1) 2 g of calcium 2-methoxyethanolate was placed in ethanol and fully dispersed to obtain a calcium 2-methoxyethanolate dispersion; 0.25 g of β-cyclodextrin was dissolved in the calcium 2-methoxyethanolate dispersion to obtain a precursor liquid; 5 g of ammonium bicarbonate was taken to prepare an ammonium bicarbonate solution, and the ammonium bicarbonate solution was slowly added to the precursor liquid at a rate of 0.1 mL / s. After the addition was completed, the container was sealed, the temperature was raised to 35°C, and the reaction was stirred at a low speed of 100 rpm for 0.5 h. After the temperature was naturally lowered and the reaction mixture was allowed to stand for 10 h, a reaction liquid containing calcium carbonate whiskers was obtained;

[0059] (2) Using calcium hydroxide to adjust the pH value of the reaction solution containing calcium carbonate whiskers to 9, then adding 0.3 g of calcium chloroacetate, reacting at 60° C. for 2 to 3 hours, rotary evaporating to remove the solvent, then washing with water until the pH of the washing solution is neutral, and drying to obtain modified calcium carbonate;

[0060] (3) Mix 3g of calcium sulfate and 0.2g of ammonium carbonate, place them in water and fully disperse them, then add 1g of β-cyclodextrin, stir and evaporate the solvent at 40°C until the solid content is 50%, raise the temperature to 60-75°C, and continue to evaporate until the weight no longer changes, thus completing the surface coating;

[0061] (4) 4 g of ammonium carbonate was dispersed in ethanol to obtain a 7 g / L ammonium carbonate ethanol dispersion; 2 g of the coated calcium sulfate was mixed with 2.5 g of modified calcium carbonate, and the mixture was placed in the ethanol dispersion containing ammonium carbonate and fully dispersed to obtain a road epoxy asphalt toughening additive.

[0062] Example 10: (1) 2 g of calcium 2-methoxyethanolate was placed in ethanol and fully dispersed to obtain a calcium 2-methoxyethanolate dispersion; 0.25 g of β-cyclodextrin was dissolved in the calcium 2-methoxyethanolate dispersion to obtain a precursor liquid; 5 g of ammonium bicarbonate was taken to prepare an ammonium bicarbonate solution, and the ammonium bicarbonate solution was slowly added to the precursor liquid at a rate of 0.1 mL / s. After the addition was completed, the container was sealed, the temperature was raised to 35°C, and the reaction was stirred at a low speed of 100 rpm for 0.5 h. After the temperature was naturally lowered and the reaction mixture was allowed to stand for 10 h, a reaction liquid containing calcium carbonate whiskers was obtained;

[0063] (2) Using calcium hydroxide to adjust the pH value of the reaction solution containing calcium carbonate whiskers to 9, then adding 0.3 g of calcium chloroacetate, reacting at 60° C. for 2 to 3 hours, rotary evaporating to remove the solvent, then washing with water until the pH of the washing solution is neutral, and drying to obtain modified calcium carbonate;

[0064] (3) Mix 3g of calcium sulfate and 0.2g of ammonium carbonate, place them in water and fully disperse them, then add 1g of β-cyclodextrin, stir and evaporate the solvent at 25°C until the solid content is 75%, raise the temperature to 60-75°C, and continue to evaporate until the weight no longer changes, thus completing the surface coating;

[0065] (4) 4 g of ammonium carbonate was dispersed in ethanol to obtain a 7 g / L ammonium carbonate ethanol dispersion; 2 g of the coated calcium sulfate was mixed with 2.5 g of modified calcium carbonate, and the mixture was placed in the ethanol dispersion containing ammonium carbonate and fully dispersed to obtain a road epoxy asphalt toughening additive.

[0066] Example 11: (1) 2 g of calcium 2-methoxyethanolate was placed in ethanol and fully dispersed to obtain a calcium 2-methoxyethanolate dispersion; 0.25 g of β-cyclodextrin was dissolved in the calcium 2-methoxyethanolate dispersion to obtain a precursor liquid; 5 g of ammonium bicarbonate was taken to prepare an ammonium bicarbonate solution, and the ammonium bicarbonate solution was slowly added to the precursor liquid at a rate of 0.1 mL / s. After the addition was completed, the container was sealed, the temperature was raised to 35°C, and the reaction was stirred at a low speed of 100 rpm for 0.5 h. After the temperature was naturally lowered and the reaction mixture was allowed to stand for 10 h, a reaction liquid containing calcium carbonate whiskers was obtained;

[0067] (2) Using calcium hydroxide to adjust the pH value of the reaction solution containing calcium carbonate whiskers to 9, then adding 0.3 g of calcium chloroacetate, reacting at 60° C. for 2 to 3 hours, rotary evaporating to remove the solvent, then washing with water until the pH of the washing solution is neutral, and drying to obtain modified calcium carbonate;

[0068] (3) Mix 3g of calcium sulfate and 0.2g of ammonium carbonate, place them in water and fully disperse them, then add 1g of β-cyclodextrin, stir and evaporate the solvent at 25°C until the solid content is 50%, raise the temperature to 60-75°C, and continue to evaporate until the weight no longer changes, thus completing the surface coating;

[0069] (4) 8 g of ammonium carbonate is dispersed in ethanol to obtain a 7 g / L ammonium carbonate ethanol dispersion; 2 g of the coated calcium sulfate is mixed with 2.5 g of modified calcium carbonate, and the mixture is placed in the ethanol dispersion containing ammonium carbonate and fully dispersed to obtain a road epoxy asphalt toughening additive.

[0070] Example 12: (1) 2 g of calcium 2-methoxyethanolate was placed in ethanol and fully dispersed to obtain a calcium 2-methoxyethanolate dispersion; 0.25 g of β-cyclodextrin was dissolved in the calcium 2-methoxyethanolate dispersion to obtain a precursor liquid; 5 g of ammonium bicarbonate was taken to prepare an ammonium bicarbonate solution, and the ammonium bicarbonate solution was slowly added to the precursor liquid at a rate of 0.1 mL / s. After the addition was completed, the container was closed, the temperature was raised to 35°C, and the reaction was stirred at a low speed of 100 rpm for 0.5 h. After the temperature was naturally lowered and the reaction mixture was allowed to stand for 10 h, a reaction liquid containing calcium carbonate whiskers was obtained;

[0071] (2) Using calcium hydroxide to adjust the pH value of the reaction solution containing calcium carbonate whiskers to 9, then adding 0.3 g of calcium chloroacetate, reacting at 60° C. for 2 to 3 hours, rotary evaporating to remove the solvent, then washing with water until the pH of the washing solution is neutral, and drying to obtain modified calcium carbonate;

[0072] (3) Mix 3g of calcium sulfate and 0.2g of ammonium carbonate, place them in water and fully disperse them, then add 1g of β-cyclodextrin, stir and evaporate the solvent at 25°C until the solid content is 50%, raise the temperature to 60-75°C, and continue to evaporate until the weight no longer changes, thus completing the surface coating;

[0073] (4) 4 g of ammonium carbonate was dispersed in ethanol to obtain a 7 g / L ammonium carbonate ethanol dispersion; 2 g of the coated calcium sulfate was mixed with 10 g of modified calcium carbonate, and the mixture was placed in the ethanol dispersion containing ammonium carbonate and fully dispersed to obtain a road epoxy asphalt toughening additive.

[0074] Preparation and testing of samples in the embodiment: basalt, limestone and limestone powder mineral materials are dried, weighed and mixed, the matrix asphalt is preheated at 120°C, the epoxy asphalt XB is preheated at 60°C, and then the epoxy asphalt XB and the matrix asphalt are mixed at a mass ratio of 60:40 to obtain epoxy asphalt; the epoxy asphalt is mixed with the preheated mineral material and stirred for 30 minutes to obtain a matrix to be cast, and the toughening additives of each embodiment are added to the matrix to be cast at an amount of 1% of the mass of the mineral material, after mixing for 5 minutes, poured into a polytetrafluoroethylene mold, and cured at 60°C for 4 days to obtain an initial epoxy asphalt sample, the cured sample is frozen at -18±2°C for 20 hours, and then naturally heated to room temperature, after repeating the freezing and heating operations 3 times, it is left to stand at room temperature at 70% humidity for 60 days, and samples are taken at 0d, 8d, 20d, and 60d, and the specimens are subjected to tensile tests using a universal testing machine, and 3 parallel experiments are performed for each experiment. The ratio of the difference between the elongation at break of the sample at 0d and 60d to the elongation at break at 0d was calculated as the growth rate to evaluate the continuous toughening effect.

[0075] The results are as follows:

[0076]

[0077] As can be seen from the above table, the tensile strength and elongation at break of the epoxy asphalt sample using the additive of the present invention are far beyond the standard of GB / T 16777-2008, indicating that the additive of the present invention can significantly increase the strength and toughness of road epoxy asphalt. It can be seen from Example 2 in which more cyclodextrin is involved in the preparation and modification of calcium carbonate whiskers and Example 7 in which the calcium chloroacetate content is higher that the inclusion modification of cyclodextrin on the surface of calcium carbonate whiskers is beneficial to improving the tensile strength of the sample, which may be related to the stronger affinity of the modified calcium carbonate whiskers with the matrix. The elongation at break of Example 3 with a higher reaction temperature and Example 4 with a faster stirring speed in step (1) is significantly reduced, indicating that a higher reaction temperature and stirring speed are not conducive to the formation of calcium carbonate whiskers, and a higher temperature may be not conducive to the control of the release rate of calcium ions and carbonate ions. The elongation at break of Example 6 and Example 6 is significantly increased, indicating that a longer reaction time and standing time are conducive to the growth of calcium carbonate whiskers.

[0078] When calcium sulfate is coated, the relative content of calcium sulfate in Example 8 is more than that in Example 1, so the relative content of ammonium carbonate is reduced, the initial elongation at break of the sample increases slowly, and the final 60d difference is also significantly reduced. It may be that the significantly reduced ammonium carbonate is not enough to produce enough holes in the coating layer for the outflow of calcium ions. The content of ammonium carbonate can be controlled in combination with the raw material selection of epoxy asphalt and the degree of environmental influence on the road to adjust the release rate of calcium ions. A higher temperature was used when the solvent was evaporated in Example 9. The solvent evaporation degree of Example 10 was higher, the growth rate of elongation at break was reduced, and the 60d difference was also reduced. Since it takes a long time to evaporate the solvent at low temperature, the higher the temperature of this step and the higher the evaporation degree, the more likely it is that the loss of ammonium carbonate will occur. The elongation at break of Example 11 increases rapidly, but the strength and initial elongation at break decrease; while the initial elongation at break of Example 12 is high, and although the growth rate is fast, it is far less than the increase in calcium carbonate. This shows that in step (4), more ammonium carbonate and more calcium sulfate are conducive to the growth of calcium carbonate whiskers and to the continuous increase in the toughness of the material, but too much ammonium carbonate is likely to affect the strength of the epoxy asphalt pavement structure. In addition, only increasing calcium carbonate whiskers without simultaneously increasing the raw materials for their growth is not enough to increase the toughening performance of the additive.

[0079] For those skilled in the art, various other corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all of these changes and deformations should fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a road epoxy asphalt toughening additive, characterized in that: Calcium carbonate whiskers are prepared by using calcium 2-methoxyethoxide and ammonium bicarbonate, and the calcium carbonate whiskers are hydrophobically modified to obtain modified calcium carbonate; calcium sulfate is surface coated, and then the coated calcium sulfate and the modified calcium carbonate are mixed and placed together in an ethanol dispersion of ammonium carbonate, and fully dispersed to obtain a road epoxy asphalt toughening additive; The preparation of the modified calcium carbonate comprises the following steps: a. Place calcium 2-methoxyethoxide in ethanol and fully disperse it to obtain a calcium 2-methoxyethoxide dispersion; dissolve cyclodextrin in the calcium 2-methoxyethoxide dispersion to obtain a precursor liquid; prepare an ammonium bicarbonate solution by taking ammonium bicarbonate, and slowly drop the ammonium bicarbonate solution into the precursor liquid. After the dropwise addition is completed, seal the container, heat it to 35-50°C, stir it at a low speed to react for 0.5-2h, cool it naturally and let it stand for 10-20h to obtain a reaction liquid containing calcium carbonate whiskers; b. Use calcium hydroxide to adjust the pH value of the reaction solution containing calcium carbonate whiskers to 8-10, then add calcium chloroacetate, react at 60-70°C for 2-3 hours, remove the solvent by rotary evaporation, then rinse with water until the pH of the washing solution is neutral, and dry to obtain modified calcium carbonate; The surface coating of calcium sulfate comprises the following steps: Mix calcium sulfate with a small amount of ammonium carbonate, place in water and fully disperse, then add cyclodextrin, stir and evaporate the solvent at 25-40°C until the solid content is 50-75%, raise the temperature to 60-75°C, and continue to evaporate until the weight no longer changes, thus completing the surface coating; The molar ratio of the calcium 2-methoxyethanolate to ammonium bicarbonate is 1:1.5-5; the mass ratio of the cyclodextrin to the calcium 2-methoxyethanolate is 1:5-8; and the mass ratio of the calcium chloroacetate to the cyclodextrin is 1.2-2.8:

1.

2. The method for preparing the road epoxy asphalt toughening additive according to claim 1, characterized in that: The mass ratio of the modified calcium carbonate to the coated calcium sulfate is 1:0.2-0.8; the mass ratio of the coated calcium sulfate to ammonium carbonate is 1:2-4; and the concentration of ammonium carbonate in the ethanol dispersion of ammonium carbonate is 4-10 g / L.

3. The method for preparing the road epoxy asphalt toughening additive according to claim 1, characterized in that: The speed of the slow dripping is 0.05-0.2 mL / s; the speed of the low-speed stirring is 100-250 rpm.

4. The method for preparing the road epoxy asphalt toughening additive according to claim 1, characterized in that: The cyclodextrin is β-cyclodextrin.

5. The method for preparing the road epoxy asphalt toughening additive according to claim 1, characterized in that: The mass ratio of the calcium sulfate to a small amount of ammonium carbonate is 15-25:1; the mass ratio of the calcium sulfate to cyclodextrin is 2.5-4:

1.

6. A road epoxy asphalt toughening additive prepared by the method according to any one of claims 1 to 5, characterized in that: The dosage in road mineral materials is 0.2~2%.

7. Use of the road epoxy asphalt toughening additive according to claim 6 in road construction, characterized in that: The mineral materials and additives used for paving are mixed with epoxy asphalt to obtain the base to be poured; before paving, the road epoxy asphalt toughening additive is added to the base to be poured, and the mixture is fully stirred to obtain the casting material, and the casting material is poured to the target position and then paving construction is carried out.

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