Waterproof dense type accelerator, preparation method and application thereof

Abstract

The application relates to the technical field of concrete admixtures, and particularly discloses a waterproof dense type accelerating agent as well as a preparation method and application thereof, which comprises the following components in parts by weight: 5-10 parts of a suspending agent, 50-250 parts of modified silica sol, 100-250 parts of an organic complex waterproof agent, 400-600 parts of an accelerating agent and water; wherein the modified silica sol is obtained by modifying acidic silica sol by a modifier, and the modifier is a silane coupling agent; and wherein the organic complex waterproof agent is an aluminum complex of a higher fatty acid. The waterproof dense type accelerating agent of the application can not cause a large amount of air entrainment of concrete after being mixed into the concrete, can fill microcracks of the sprayed concrete, and can improve the compactness of the concrete; meanwhile, the waterproof effect is formed on the inside and the surface of the sprayed concrete; and the addition of the organic complex waterproof agent can promote the coagulation of the concrete, and the accelerating agent can realize the rapid coagulation of the concrete.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of concrete admixtures, in particular to a waterproof dense type accelerator and a preparation method and application thereof. BACKGROUND

[0002] Sprayed concrete is a kind of concrete that is sprayed at high speed to the sprayed surface by spraying equipment and quickly hardens after spraying, which is widely used in tunnel engineering, water conservancy engineering, coal mine construction, mine repair and slope protection. Since the sprayed concrete uses high-pressure air to blow the concrete at high speed to the inner wall of the tunnel, there is no conventional concrete vibrating process, so that the sprayed concrete has poor compactness and more cavities after solidification. The environment in the tunnel is harsh, and water, inorganic salts and other substances in the mountain continuously erode the sprayed concrete structure. In addition, the sprayed concrete itself has more cavities and insufficient compactness, which causes serious corrosion of the steel bars and arches in the sprayed concrete. This situation seriously weakens the supporting effect of the sprayed concrete and shortens the service life of the tunnel.

[0003] CN201910533370.4 provides a waterproof type alkali-free liquid accelerator with water reducing function. The waterproof accelerator uses lithium stearate obtained by the reaction of stearic acid and lithium hydroxide as a raw material. This substance has strong surface activity and can introduce a large amount of air in the sprayed concrete, which reduces the compactness and strength of the concrete.

[0004] CN202410130511.9 also provides a waterproof type powder accelerator. The waterproof type powder accelerator uses hydroxyethyl cellulose modified stearic acid, which also introduces a large amount of air in the concrete, reduces the compactness and strength of the concrete. SUMMARY

[0005] The purpose of the present application is to provide a waterproof dense type accelerator which does not cause a large amount of air entrainment in concrete after being mixed into the concrete, to solve the problem of poor compactness caused by the existing accelerator mixed into the concrete, and to achieve rapid solidification of the concrete, so that the internal and surface of the sprayed concrete form a hydrophobic effect.

[0006] In addition, the present application also provides a preparation method and application of the above-mentioned waterproof dense type accelerator.

[0007] The present application is realized by the following technical scheme:

[0008] A waterproof dense type accelerator comprises the following components by weight:

[0009] 5-10 parts of a suspending agent, 50-250 parts of modified silica sol, 100-250 parts of an organic complex waterproof agent, 400-600 parts of a coagulant, and water.

[0010] The modified silica sol is obtained by modifying an acidic silica sol with a modifier, and the modifier is a silane coupling agent.

[0011] The organic complex waterproofing agent is an aluminum complex of a higher fatty acid.

[0012] The present application obtains modified silica sol by modifying the acid silica sol with a silane coupling agent. The silicon hydroxyl groups in the coupling agent condense with the hydroxyl groups on the surface of the acid silica sol, which seals part of the hydroxyl groups in the acid silica sol, prevents the acid silica sol from self-polymerization, and improves the stability of the acid silica sol. In addition, the lipophilic component in the coupling agent also gives the acid silica sol certain water-repellent properties. Therefore, the introduction of the modified silica sol can not only fill the micro-cracks of the sprayed concrete, but also react with the calcium hydroxide generated by the hydration of cement to generate calcium silicate hydrate, thereby improving the strength of the sprayed concrete.

[0013] The organic complex waterproofing agent of the present application is an aluminum complex of a higher fatty acid. The paraffin group has excellent hydrophobic effect. In the sprayed concrete system, the component can complex with the calcium ions generated by the hydration of cement to form a higher fatty acid calcium waterproofing material, and the released aluminum ions can participate in the setting of the sprayed concrete.

[0014] In summary, the waterproof and dense type of accelerator of the present application, when mixed into concrete, will not cause the concrete to have a large amount of air entrainment, and can fill the micro-cracks of the sprayed concrete, thereby improving the density of the concrete. At the same time, the organic complex waterproofing agent and the modified silica sol can achieve the waterproof and water-repellent properties of the concrete, realizing the formation of a hydrophobic effect inside and on the surface of the sprayed concrete. The addition of the organic complex waterproofing agent can promote the setting of the concrete, and the combination of the accelerator and the setting accelerator can achieve rapid setting of the concrete.

[0015] Specifically, the preparation process of the modified silica sol is as follows:

[0016] After 500-600 parts of acid silica sol with a content of 30% is heated to 40-45℃ in a water bath, 200-250 parts of a modifier and 150-200 parts of ethanol are added, and the reaction is carried out for 1-1.5h to obtain the modified silica sol. The silane coupling agent used for modification at least includes one of tridecafluorooctyltriethoxysilane and n-octyltriethoxysilane.

[0017] Specifically, the preparation process of the organic complex waterproofing agent is as follows:

[0018] 20-30 parts of amorphous aluminum hydroxide is slowly added to 80-100 parts of an organic acid complexing agent, and slowly stirred for 3-4h to obtain the organic complex waterproofing agent. The organic acid complexing agent at least includes one of oleic acid and erucic acid.

[0019] In a preferred mode, the preparation process of the setting accelerator is as follows:

[0020] Mix 180-250 parts of water, 100-130 parts of aluminum hydroxide, 200-280 parts of 40% mass fraction of fluosilicic acid, 300-400 parts of aluminum sulfate, and then heat to 80-85 DEG C in water bath, stir for 2-3 hours, then put in 50-80 parts of sodium metaaluminate solution, continue to stir for 1-1.5 hours, and then cool down to obtain the coagulant accelerator.

[0021] The coagulant accelerator prepared by the method can well realize the coagulation of concrete.

[0022] In a preferred mode, the preparation process of the sodium metaaluminate solution is as follows:

[0023] Mix 250 parts of sodium hydroxide, 400 parts of aluminum hydroxide and 350 parts of water, heat to 110-115 DEG C in oil bath, and react for 1.5-2 hours to obtain the sodium metaaluminate solution.

[0024] In a preferred mode, the suspending agent is a modified suspending agent, the modified suspending agent is obtained by silane coupling modification, and the suspending agent is magnesium silicate hydrate.

[0025] Specifically, the preparation process of the modified suspending agent is as follows:

[0026] Dissolve the silane coupling agent KH-550 in the ethanol aqueous solution, put into the suspending agent, and then perform surface modification on the suspending agent at room temperature, stir for 1-1.5 hours, and then obtain the modified suspending agent.

[0027] The present application modifies the surface of the suspending agent by silane coupling, so that the surface of the suspending agent has a slight lipophilic effect, the affinity with the modified silica sol and the organic complex waterproof agent is enhanced, and the stratification of the suspension is prevented.

[0028] The preparation method of the waterproof dense type accelerating agent includes the following steps:

[0029] Add water in a container, start high-speed dispersion, add the suspending agent, stir for 0.5-1 hour, then add the organic complex waterproof agent, continue to disperse for 1-1.5 hours, put in the modified silica sol and the coagulant accelerator, and then continue to disperse for 2-3 hours to obtain the waterproof dense type accelerating agent.

[0030] The waterproof dense type accelerating agent is applied to the preparation of the sprayed concrete.

[0031] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0032] The waterproof compact type accelerator of the present application, with the waterproof component, can react with calcium ions in the concrete to form calcium complex after being mixed into the sprayed concrete, so as to change the hydrophilic property of the concrete into hydrophobic property; in addition to making the sprayed concrete solidify rapidly, the waterproof compact type accelerator can increase the compactness of the sprayed concrete, reduce the tiny pores of the sprayed concrete, and form the hydrophobic effect on the inside and surface of the sprayed concrete, so that water is difficult to penetrate into the inside of the concrete, and the corrosion of water and inorganic salts in water to the concrete and steel bars is avoided. The waterproof type accelerator can obviously solve the durability problem of the sprayed concrete, and has a wide application prospect in this field. BRIEF DESCRIPTION OF DRAWINGS

[0033] The accompanying drawings, which are included to provide a further understanding of the embodiments of the present application and are incorporated in and constitute a part of this application, illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application. In the drawings:

[0034] Figure 1 Picture of mortar test block after water dripping for the sprayed concrete prepared by mixing the accelerator prepared in Example 1 of the present application;

[0035] Figure 2 Picture of mortar test block after water dripping for the sprayed concrete prepared by mixing the accelerator prepared in Example 2 of the present application;

[0036] Figure 3 Picture of mortar test block after water dripping for the sprayed concrete prepared by mixing the accelerator prepared in Example 3 of the present application;

[0037] Figure 4 Picture of mortar test block after water dripping for the sprayed concrete prepared by mixing the accelerator prepared in Example 4 of the present application;

[0038] Figure 5 Picture of mortar test block after water dripping for the sprayed concrete prepared by mixing the accelerator prepared in Example 5 of the present application;

[0039] Figure 6 Picture of mortar test block after water dripping for the sprayed concrete prepared by mixing the accelerator prepared in Comparative Example 1 of the present application;

[0040] Figure 7 Picture of mortar test block after water dripping for the sprayed concrete prepared by mixing the accelerator prepared in Comparative Example 2 of the present application;

[0041] Figure 8 Picture of mortar test block after water dripping for the sprayed concrete prepared by mixing the accelerator prepared in Comparative Example 3 of the present application. DETAILED DESCRIPTION

[0042] In order to make the objects, technical solutions and advantages of the present application clearer, further detailed description will be made to the present application in combination with embodiments, the illustrative embodiments and the description thereof are only used to explain the present application, and do not limit the present application. The embodiments described below are part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of protection of the present application.

[0043] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without these specific details. In other instances, well-known structures, materials or methods have not been described in detail in order to avoid obscuring the present application. The materials, instruments and reagents used in the following embodiments, unless otherwise specified, can be obtained commercially. The technical means used in the embodiments, unless otherwise specified, are conventional means known to those skilled in the art.

[0044] In addition, the terms "first", "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified.

[0045] Embodiment:

[0046] In order to solve the problem that the existing accelerator makes the compactness of concrete worse and the strength of concrete decreases after being incorporated into the concrete, the present embodiment provides a waterproof compact accelerator, which comprises the following components by weight:

[0047] 5-10 parts of suspending agent, 50-250 parts of modified silica sol, 100-250 parts of organic complex waterproof agent, 400-600 parts of accelerator, and water.

[0048] The modified silica sol is obtained by modifying the acid silica sol with a modifier, and the modifier is a silane coupling agent. The preparation process of the modified silica sol is as follows: 500-600 parts of acid silica sol with a content of 30% is heated to 40-45°C in a water bath, and then 200-250 parts of the modifier and 150-200 parts of ethanol are added and reacted for 1-1.5 hours to obtain the modified silica sol. The silane coupling agent used for modification at least includes one of tridecafluorooctyltriethoxysilane and n-octyltriethoxysilane.

[0049] The organic complex waterproofing agent is an aluminum complex of a higher fatty acid; the organic complex waterproofing agent is prepared by slowly adding 20-30 parts of amorphous aluminum hydroxide to 80-100 parts of an organic acid complexing agent, and stirring slowly for 3-4 hours to obtain the organic complex waterproofing agent; the organic acid complexing agent includes at least one of oleic acid and erucic acid.

[0050] The accelerator promotes the setting of the concrete; the accelerator is prepared by mixing 180-250 parts of water, 100-130 parts of aluminum hydroxide, 200-280 parts of fluosilicic acid with a mass fraction of 40%, and 300-400 parts of aluminum sulfate, heating in a water bath to 80-85°C, stirring and reacting for 2-3 hours, adding 50-80 parts of sodium metaaluminate solution, and continuing to stir for 1-1.5 hours to obtain the accelerator.

[0051] The accelerator promotes the setting of the concrete; the accelerator is prepared by mixing 180-250 parts of water, 100-130 parts of aluminum hydroxide, 200-280 parts of fluosilicic acid with a mass fraction of 40%, and 300-400 parts of aluminum sulfate, heating in a water bath to 80-85°C, stirring and reacting for 2-3 hours, adding 50-80 parts of sodium metaaluminate solution, and continuing to stir for 1-1.5 hours to obtain the accelerator.

[0052] The sodium metaaluminate solution is prepared by mixing 250 parts of sodium hydroxide, 400 parts of aluminum hydroxide, and 350 parts of water, heating in an oil bath to 110-115°C, and reacting for 1.5-2 hours to obtain the sodium metaaluminate solution.

[0053] The sodium metaaluminate solution is prepared by mixing 250 parts of sodium hydroxide, 400 parts of aluminum hydroxide, and 350 parts of water, heating in an oil bath to 110-115°C, and reacting for 1.5-2 hours to obtain the sodium metaaluminate solution.

[0054] The suspension agent promotes the stratification of the suspension; in one preferred case, the suspension agent is a modified suspension agent, which is obtained by modifying a suspension agent with a silane coupling agent; the suspension agent is magnesium silicate hydrate; the modified suspension agent is prepared by dissolving a silane coupling agent KH-550 in an aqueous ethanol solution, adding the suspension agent, and modifying the surface of the suspension agent at room temperature, and stirring for 1-1.5 hours to obtain the modified suspension agent.

[0055] The waterproofing and compacting type accelerator of the present embodiment is mixed into the sprayed concrete; in addition to rapidly setting the sprayed concrete, the waterproofing and compacting type accelerator can also improve the compactness of the sprayed concrete, reduce air bubbles and micro-cracks, and improve the strength of the sprayed concrete; the waterproofing component in the accelerator can react with calcium ions in the concrete to form calcium complexes, so that the concrete changes from hydrophilic to hydrophobic.

[0056] 1) The acid silicasol is modified: the acid silicasol is modified by a silane coupling agent such as tridecafluoro-octyltriethoxysilane and n-octyltriethoxysilane; the silicon hydroxyl groups in the silane coupling agent condense with the hydroxyl groups on the surface of the silicasol, so that part of the hydroxyl groups in the silicasol are blocked, preventing the silicasol from self-polymerizing, and improving the stability of the acid silicasol; in addition, the lipophilic component in the coupling agent also gives the silicasol certain water-repellent properties; the introduction of the silicasol can not only fill the micro-cracks in the sprayed concrete, but also react with calcium hydroxide produced by the hydration of cement to form calcium silicate hydrate, thereby improving the strength of the sprayed concrete.

[0057] 2) By preparing an organic complex waterproofing agent, which is dispersed into the accelerator at high speed, the organic complex waterproofing agent is an aluminum complex of higher fatty acid, and the long-chain alkyl group has excellent hydrophobic effect. This component can complex with calcium ions generated by the hydration of cement in the sprayed concrete system to form a calcium waterproofing material of higher fatty acid, and the released aluminum ions can participate in the setting of the sprayed concrete.

[0058] 3) By surface modification of the suspending agent, the surface of the suspending agent has a slight lipophilic effect, which enhances its affinity with modified silica sol and organic complex waterproofing agent, and prevents the suspension from stratifying.

[0059] In summary, the waterproof dense type accelerator can enhance the waterproof effect of the sprayed concrete, increase the density of the sprayed concrete, and improve the strength of the sprayed concrete, thereby improving the durability of the sprayed concrete. Therefore, the accelerator can fundamentally improve the current situation that the sprayed concrete can only be used for initial support and cannot be used for long-term support, and has a wide application prospect in this field.

[0060] The preparation method of the waterproof dense type accelerator comprises the following steps:

[0061] In the container, add water, start high-speed dispersion, add suspending agent, stir for 0.5-1 h, then add organic complex waterproofing agent, continue to disperse for 1-1.5 h, add modified silica sol and setting accelerator, continue to disperse for 2-3 h, and obtain the waterproof dense type accelerator.

[0062] The waterproof dense type accelerator can be used for preparing sprayed concrete.

[0063] In order to better illustrate the technical effect of the embodiment, the following technical case is used for illustration:

[0064] Example 1:

[0065] A waterproof dense type accelerator is composed of the following components by weight:

[0066] Modified suspending agent 10 parts, modified silica sol 200 parts, organic complex waterproofing agent 100 parts, setting accelerator 500 parts, and water 190 parts.

[0067] The preparation method of the waterproof dense type accelerator is as follows: in a 1L three-necked bottle, add 190 parts of deionized water, start high-speed dispersion, rotate at 1200 r / min, first add 10 parts of modified suspending agent, stir for 0.5 h, then add 100 parts of organic complex waterproofing agent, continue to disperse for 1 h, then add 200 parts of modified silica sol and 500 parts of setting accelerator, and continue to disperse for 2 h, to obtain the waterproof type accelerator.

[0068] The preparation process of the modified silica sol is as follows:

[0069] Put the 550 parts of the purchased acid silica sol (content 30%) into a 3-necked flask, heat to 40℃ in water bath, then put in 200 parts of tridecafluorooctyltriethoxysilane and 250 parts of ethanol, and react for 1h to obtain modified silica sol.

[0070] The preparation process of the organic complex waterproof agent is as follows:

[0071] A, put 250 parts of sodium hydroxide, 400 parts of aluminum hydroxide, and 350 parts of water into a 3-necked flask, heat to 110℃ in oil bath, and react for 1.5h to obtain sodium metaaluminate solution. Take 100 parts of the prepared sodium metaaluminate solution and put it into 500 parts of aluminum oxide content of 7.5% aluminum sulfate solution to produce a large amount of precipitate. The precipitate is filtered, washed, and dried at low temperature and reduced pressure to obtain amorphous aluminum hydroxide.

[0072] B, slowly put 30 parts of amorphous aluminum hydroxide into 80 parts of organic acid complexing agent (erucic acid), and slowly stir for 3h to obtain an organic complex waterproof agent.

[0073] The preparation process of the accelerator is as follows:

[0074] Put 200 parts of water, 130 parts of aluminum hydroxide, 280 parts of fluosilicic acid (mass fraction 40%), and 300 parts of aluminum sulfate into a 3-necked flask, heat to 80℃ in water bath, and stir for 2h. Then put in 80 parts of the above sodium metaaluminate solution, continue to stir for 1h, and cool to obtain the accelerator component.

[0075] The preparation process of the modified suspension agent is as follows:

[0076] Put 10 parts of silane coupling agent KH-550 into 20 parts of mixed solution of ethanol and water (ethanol and water mass ratio 1:1) in a 3-necked flask, then put in 50 parts of suspension agent magnesium silicate hydrate, and modify the surface of the suspension agent at room temperature. Stir for 1h to obtain a modified suspension agent.

[0077] Example 2:

[0078] This example is based on Example 1, and the difference between the examples is:

[0079] The modifier used in the modified acid silica sol is n-octyltriethoxysilane; the organic acid complexing agent used in the preparation process of the organic complex waterproof agent is oleic acid;

[0080] Example 3:

[0081] This example is based on Example 1, and the difference between the examples is:

[0082] The amount of each component in the waterproof dense type accelerator is different, specifically, the amount of the organic complex waterproof agent is increased and the amount of the modified silica sol is reduced, and the preparation method of each component is the same as that in Example 1. Specifically,

[0083] A waterproof dense type accelerator is composed of the following components by weight:

[0084] Modified suspending agent 10 parts, modified silica sol 100 parts, organic complex waterproof agent 200 parts, coagulant 500 parts, and water 190 parts.

[0085] The preparation method of the waterproof dense type accelerator is as follows: in a 1L three-necked flask, 190 parts of deionized water are added, high-speed dispersion is started, the speed is 1200r / min, 10 parts of modified suspending agent are first added, stirring is carried out for 0.5h, then 200 parts of organic complex waterproof agent are added, and dispersion is continued for 1h, then 100 parts of modified silica sol and 500 parts of coagulant are added, and dispersion is continued for 2h to obtain the waterproof type accelerator.

[0086] Example 4:

[0087] This example is based on Example 1, and the difference from the example is that:

[0088] The amount of each component in the waterproof dense type accelerator is different, specifically, the amount of the organic complex waterproof agent is increased, and the preparation method of each component is the same as that in Example 1. Specifically:

[0089] A waterproof dense type accelerator is composed of the following components by weight:

[0090] Modified suspending agent 10 parts, modified silica sol 200 parts, organic complex waterproof agent 200 parts, coagulant 500 parts, and water 190 parts.

[0091] The preparation method of the waterproof dense type accelerator is as follows: in a 1L three-necked flask, 190 parts of deionized water are added, high-speed dispersion is started, the speed is 1200r / min, 10 parts of modified suspending agent are first added, stirring is carried out for 0.5h, then 200 parts of organic complex waterproof agent are added, and dispersion is continued for 1h, then 200 parts of modified silica sol and 500 parts of coagulant are added, and dispersion is continued for 2h to obtain the waterproof type accelerator.

[0092] Example 5:

[0093] This example is based on Example 1, and the difference from the example is that:

[0094] The amount of each component in the waterproof dense type accelerator is different, specifically, the amount of the organic complex waterproof agent is increased and the amount of the modified silica sol is increased, and the preparation method of each component is the same as that in Example 1. Specifically:

[0095] A waterproof dense type accelerator is composed of the following components by weight:

[0096] Modified suspending agent 10 parts, modified silica sol 250 parts, organic complex waterproof agent 250 parts, coagulant 500 parts, water 190 parts.

[0097] The preparation method of the waterproof dense type accelerator is as follows: in a 1L three-necked flask, 190 parts of deionized water is added, high-speed dispersion is started, the rotating speed is 1200r / min, 10 parts of modified suspending agent is first added, stirring for 0.5h, then 250 parts of organic complex waterproof agent is added, and continues to be dispersed for 1h, then 250 parts of modified silica sol and 500 parts of coagulant are added, and continues to be dispersed for 2h, to obtain the waterproof type accelerator.

[0098] Comparative Example 1:

[0099] This comparative example is based on Example 1, and the difference from the example is that:

[0100] The waterproof dense type accelerator does not contain modified silica sol in the formula, and the amount of organic complex waterproof agent and water is increased, and the specific amount is as follows:

[0101] A waterproof dense type accelerator is composed of the following components by weight:

[0102] Modified suspending agent 10 parts, organic complex waterproof agent 200 parts, coagulant 500 parts, water 290 parts.

[0103] The preparation method of the waterproof dense type accelerator is as follows: in a 1L three-necked flask, 290 parts of deionized water is added, high-speed dispersion is started, the rotating speed is 1200r / min, 10 parts of modified suspending agent is first added, stirring for 0.5h, then 200 parts of organic complex waterproof agent is added, and continues to be dispersed for 1h, then 500 parts of coagulant is added, and continues to be dispersed for 2h, to obtain the waterproof type accelerator.

[0104] Comparative Example 2:

[0105] This comparative example is based on Example 1, and the difference from the example is that:

[0106] The waterproof dense type accelerator does not contain organic complex waterproof agent in the formula, and the specific amount is as follows:

[0107] A waterproof dense type accelerator is composed of the following components by weight:

[0108] Modified suspending agent 10 parts, modified silica sol 200 parts, coagulant 500 parts, water 290 parts.

[0109] The preparation method of the waterproof dense type accelerator is as follows: 290 parts of deionized water are added into a 1L three-necked flask, high-speed dispersion is started, the rotating speed is 1200r / min, 10 parts of modified suspending agent is first added, stirring is carried out for 0.5h, 200 parts of modified silica sol is added, and dispersion is continuously carried out for 1h, then 500 parts of coagulant is added, and dispersion is continuously carried out for 2h to obtain the waterproof type accelerator.

[0110] Comparative Example 3:

[0111] This comparative example is based on Example 1, and the difference from the example is that:

[0112] No modified silica sol and no organic complex waterproof agent.

[0113] The preparation method of the common accelerator is as follows: 490 parts of deionized water are added into a 1L three-necked flask, high-speed dispersion is started, the rotating speed is 1200r / min, 10 parts of modified suspending agent is first added, dispersion is carried out for 0.5h, and then 500 parts of coagulant is added, and dispersion is continuously carried out for 2h to obtain the blank accelerator.

[0114] Performance test:

[0115] 1. Setting time and compressive strength test

[0116] The setting time and 1-day compressive strength of the accelerator are tested according to GB / T 35159-2017 "Accelerator for Shotcrete".

[0117] The reference cement (produced in July 2024), the accelerator dosage is 6%, the setting time (00:00) test ratio is cement 400g, water 140g, the compressive strength (MPa) test ratio is cement 900g, water 450g, standard sand 1350g; the test data of setting time and compressive strength are shown in Table 1:

[0118] Table 1

[0119]

[0120] From Table 1, it can be seen that:

[0121] 1) From Comparative Example 1 and Comparative Example 3, it can be seen that the addition of organic complex waterproof agent can reduce the mortar strength;

[0122] 2) From Comparative Example 2 and Comparative Example 3, it can be seen that the addition of modified silica sol can increase the mortar strength, which shows that the improved silica sol can increase the compactness of the mortar test block;

[0123] 3) From Example 1, Example 2 and Comparative Example 3, it can be seen that the combined use of organic complex waterproof agent and modified silica sol can ensure that the mortar strength is higher than the reference;

[0124] 4) Compared with Example 4, the mechanical properties of the mortar are improved after increasing the modified silica sol.

[0125] 2, Water absorption test of mortar test block

[0126] According to GB / T 35159-2017 "Accelerating agent for shotcrete", the mortar test block is formed, and the 48-hour water absorption rate is measured. The specific operation method is as follows:

[0127] 1) The mortar test blocks doped with different waterproof and dense accelerating agents and ordinary accelerating agents are cured under standard curing conditions, and after curing for 28 days, they are dried in an oven at 40°C to constant weight, and then placed at room temperature for 24h. At this time, the mass of each mortar test block is recorded as m0,

[0128] 2) Each mortar test block is placed in a water bath, and the water surface is 3mm higher than the surface of the mortar test block. After 48 hours, the test block is taken out, the surface water is absorbed with filter paper, and then the mass is measured, recorded as m1,

[0129] 3) The 48-hour water absorption rate of the mortar test block is calculated according to the following formula:

[0130] The results are shown in Table 2:

[0131] Table 2

[0132]

[0133] From Table 2, it can be seen that:

[0134] 1) From Example 1, Example 2 and Comparative Example 3, the waterproof effect of the system of tridecafluorooctyltriethoxysilane combined with erucic acid is better than that of n-octyltriethoxysilane;

[0135] 2) From Example 1 and Example 3, increasing the amount of organic complex waterproofing agent component can further improve the waterproof effect of the mortar test block, but the improvement is limited;

[0136] 3) From Comparative Example 1, Comparative Example 2 and Comparative Example 3, the use of modified silica sol and organic complex waterproofing agent alone has certain waterproof effect, but the effect of organic complex waterproofing agent is more obvious;

[0137] 4) From Example 4, Example 5 and Example 3, increasing the amount of organic complex waterproofing component and tridecafluorooctyltriethoxysilane can reduce the water absorption rate and improve the waterproof effect.

[0138] 3, Internal waterproof effect observation of mortar test block

[0139] After testing the compressive strength of the mortar test block, distilled water is gently dropped on the fracture section of the mortar test block, and the waterproof effect inside the mortar is observed. The test pictures of the mortar test blocks prepared by incorporating the accelerating agents of Example 1-Example 5, Comparative Example 1-Comparative Example 3 are shown in Figures 1-8

[0140] It can be seen that: Figures 1-8

[0141] 1) Compared with Comparative Example 1, Comparative Example 2 and Comparative Example 3, the water droplets in Comparative Example 1 cannot spread, indicating that the organic complex waterproof agent forms a good waterproof structure inside the mortar. The water droplets in Comparative Example 2 spread to a certain extent, which is slightly better than Comparative Example 3 (blank), indicating that the modified silica sol only has a certain waterproof effect.

[0142] 2) As can be seen from Example 1-5, the combination of modified silica sol and organic complex waterproof material still has good internal waterproofing of the mortar test block.

[0143] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.​​

Claims

1. A waterproofing compact type accelerator, characterized by, Comprising the following parts by weight: 5~10 parts of suspending agent, 200~250 parts of modified silica sol, 200~250 parts of organic complex waterproof agent, 400~600 parts of coagulant, water; The modified silica sol is obtained by modifying acidic silica sol with a modifying agent, and the modifying agent is tridecafluorooctyltriethoxysilane; the preparation process of the modified silica sol is as follows: After 500~600 parts of acidic silica sol with a content of 30% is heated to 40-45℃ in a water bath, 200~250 parts of the modifying agent and 150~200 parts of ethanol are added, and the reaction is carried out for 1-1.5h to obtain the modified silica sol; The organic complex waterproof agent is an aluminum complex of a higher fatty acid; the preparation process of the organic complex waterproof agent is as follows: 20~30 parts of amorphous aluminum hydroxide is slowly added to 80~100 parts of an organic acid complexing agent, and slowly stirred for 3-4h to obtain the organic complex waterproof agent, and the organic acid complexing agent is erucic acid.

2. A waterproofing densifying type accelerator according to claim 1, characterized in that, The preparation process of the coagulant is as follows: After 180~250 parts of water, 100~130 parts of aluminum hydroxide, 200~280 parts of fluorosilicic acid with a mass fraction of 40%, and 300~400 parts of aluminum sulfate are mixed, water bath heating is carried out to 80-85℃, and stirring is carried out for 2-3h, then 50~80 parts of sodium metaaluminate solution is added, and stirring is continued for 1-1.5h, and then cooling is carried out to obtain the coagulant.

3. A waterproofing densifying type accelerator according to claim 2, characterized in that, The preparation process of the sodium metaaluminate solution is as follows: After 250 parts of sodium hydroxide, 400 parts of aluminum hydroxide, and 350 parts of water are mixed, oil bath heating is carried out to 110-115℃, and the reaction is carried out for 1.5-2h to obtain the sodium metaaluminate solution.

4. A waterproofing densifying type accelerator according to claim 1, wherein The suspending agent is a modified suspending agent, and the modified suspending agent is obtained by silane coupling modification of the suspending agent, and the suspending agent is hydrated magnesium silicate.

5. A waterproofing densifying type accelerator according to claim 4, wherein The preparation process of the modified suspending agent is as follows: The silane coupling agent KH-550 is dissolved in an ethanol aqueous solution, and then added to the suspending agent, and the surface of the suspending agent is modified at room temperature, and stirring is carried out for 1-1.5h to obtain the modified suspending agent.

6. A method for preparing a water-repelling dense type accelerator according to any one of claims 1 to 5, characterized in that, Comprising the following steps: Water is added to a container, high-speed dispersion is started, the suspending agent is added, the organic complex waterproof agent is added after stirring for 0.5-1h, and the dispersion is continued for 1-1.5h, then the modified silica sol and the coagulant are added, and the dispersion is continued for 2-3h to obtain the waterproof dense type accelerator.

7. The use of the waterproof dense type accelerator according to any one of claims 1-5 in the preparation of shotcrete.

Images