CN110218019A - Early high-strength compound alkali-free liquid accelerator, preparation method and gunite concrete - Google Patents

Abstract

The application discloses an early high-strength composite non-alkali liquid quick-setting agent, a preparation method and shotcrete. The non-alkali liquid quick-setting agent includes the following components in parts by weight: aluminum sulfate: 45% to 55%; active hydroxide Aluminum: 5% to 10%; Fluoride: 5% to 10%; Alcoholamine: 1.5% to 4%; Polyacrylamide: 0.5% to 1%; Organic water reducer: 1% to 3%; Stabilizer : 0.8% to 1%; water: 25% to 35%.

Description

Early high-strength composite non-alkali liquid quick-setting agent, preparation method and sprayed concrete

technical field

The present disclosure generally relates to the technical field of building materials, and specifically relates to an early high-strength composite alkali-free liquid accelerator, a preparation method and shotcrete, which are mainly used in shotcrete for geotechnical engineering such as tunnels, mines, and slopes.

Background technique

Accelerator is an admixture that can quickly set and harden concrete. It is an essential material in shotcrete. Its function is to accelerate the rapid setting and hardening of shotcrete, increase the thickness of a shot, reduce the rebound loss, and prevent the concrete from It falls off due to gravity, and can effectively hold and wrap steel bars and arch frames to form a reinforced concrete support structure. Accelerator is mainly used in geotechnical engineering such as anchor shotcrete support, tunnel, mine, deep foundation pit, water conservancy, slope, etc., and is widely used.

Accelerators are divided into powder accelerators and liquid accelerators. Among them, powder accelerators are mainly used in dry sprayed concrete. Due to the large amount of rebound and dust in dry sprayed concrete, the strength of concrete in the later stage Due to the problems of large losses and low construction efficiency, the use of it is gradually reduced in projects. In some tunnel specifications, it has been clearly stated that the use of dry shotcrete is prohibited. Liquid accelerators are mainly used in wet sprayed concrete, which has low dust, high construction efficiency, and high concrete strength, and is being popularized and applied in a large area. The development of wet spray must also be accompanied by the development of liquid accelerators.

At present, liquid accelerators are mainly divided into two types: alkaline and non-alkali. Alkaline liquid accelerators are mainly sodium aluminate type and sodium silicate type. Due to strong alkalinity, alkali-aggregate reaction is prone to occur. The strength loss is serious, and the alkalinity is harmful to the human body. Alkali-free liquid accelerators are gradually replacing alkaline liquid accelerators and becoming the development trend of liquid accelerators due to their high long-term strength retention rate, alkali-free and chlorine-free, safety and environmental protection, and high durability.

The existing non-alkali liquid quick-setting agent has a large dosage (7% to 12% of the cement mass), single material performance, poor adaptability to different cements, low setting acceleration effect, less active active ingredients and poor stability, and the early strength of concrete Problems such as low price and high price make the promotion of non-alkali liquid accelerator very difficult. Therefore, it is necessary to further research and develop the non-alkali liquid accelerator.

Contents of the invention

In view of the above-mentioned defects or deficiencies in the prior art, it is desired to provide an early high-strength composite alkali-free liquid accelerator and a preparation method thereof. The quick-setting agent can effectively increase the concentration of the solution, greatly reduce the dosage of the quick-setting agent, shorten the initial and final setting time, improve construction efficiency, improve the early strength and later strength of shotcrete, and have good adaptability to different cements. During on-site construction, it can effectively reduce rebound and dust, and improve the effect of shotcrete support.

In order to achieve the above purpose and other related purposes, the present invention is achieved through the following technical solutions.

One aspect of the present invention provides an early high-strength composite non-alkali liquid quick-setting agent, and the non-alkali liquid quick-setting agent comprises the following components by weight:

Aluminum sulfate 45% to 55%;

Activated aluminum hydroxide 5% to 10%;

Fluoride salt 5% to 10%;

Alcoholamine 1.5%~4%;

Polyacrylamide 0.5% ~ 1%;

Organic water reducer 1% to 3%;

Stabilizer 0.8% ~ 1%;

Water 25%～35%.

In some embodiments of the embodiments of the present application, the fluoride salt is selected from one or more of sodium fluoride, potassium fluoride, and magnesium fluoride.

In some embodiments of the embodiments of the present application, the alcohol amine is selected from one of diethanolamine, triethanolamine, monoethanolamine, dimethylethanolamine, diethylethanolamine, methyldiethanolamine, ethyldiethanolamine or Various combinations.

Further, the alcohol amine includes triethanolamine, and the weight portion of the triethanolamine is 0.5%-1%.

Further, the alcohol amine includes diethanolamine, and the weight portion of the diethanolamine is 1%-3%.

In some embodiments of the embodiments of the present application, the organic water reducer is polyethylene glycol polycondensate.

In some embodiments of the embodiments of the present application, the stabilizer is hydrated magnesium silicate.

On the other hand the present invention provides a kind of preparation method of early high-strength composite alkali-free liquid accelerator, comprising the following steps:

Step 1: mixing fluoride salt, diethanolamine and water to obtain a fluoride salt solution;

Step 2: heating the fluoride salt solution to 60-70° C., adding aluminum sulfate, activated aluminum hydroxide and a stabilizer, and stirring at a high speed to obtain a mother liquor of an alkali-free accelerator;

Step 3: Add alcohol amine, polyacrylamide and organic water reducer to the mother liquor of the alkali-free quick-setting agent, control the temperature at 40-60°C, and obtain the early-high-strength composite alkali-free liquid accelerator after filtration .

In some embodiments of the present invention, one or more of the following technical features are also included:

A1) In step 1, add sodium fluoride into water at room temperature, stir rapidly for 10-30 minutes, then add diethanolamine, and continue stirring for 10-20 minutes to obtain a sodium fluoride solution;

A2) In step 2, when the sodium fluoride solution is heated to 60-70°C, aluminum sulfate and activated aluminum hydroxide are added several times, and high-speed shear stirring is performed at 500-800 rpm/min, and then a stabilizer is added. The temperature is controlled at about 70°C, the stirring time is 90-150min, and the mother liquor of alkali-free accelerator is initially obtained;

A3) In step 3, compound the mother liquor of alkali-free quick-setting agent, add triethanolamine, polyacrylamide and organic water reducer, control the temperature at 40-60°C, and stir at a speed of 300-500rpm/min. The time is 60-90 minutes, and the said early-high-strength composite alkali-free liquid quick-setting agent can be obtained after filtering.

In a third aspect, the present invention provides a kind of shotcrete, which includes the above-mentioned early high-strength composite alkali-free liquid quick-setting agent, and the dosage of the alkali-free liquid quick-setting agent is 3% of the cement quality in the shotcrete ~5%;

The cement variety adaptation coefficient _ca of the alkali-free liquid quick-setting agent is less than 0.8,

Wherein, the test method of described cement variety adaptation coefficient is:

The non-alkali liquid quick-setting agent is applied to five test cement varieties at a dosage of 4%, and the dispersion coefficients of various sub-indexes are obtained for different cement types, and the sub-items include initial setting time index and final setting time index , 1d intensity index and 28d intensity ratio index, the adaptation coefficient ca is the _sum of the dispersion coefficients of each of the sub-items.

The specific method is:

The non-alkali liquid quick-setting agent was applied to five kinds of test cement varieties with a dosage of 4% to carry out the setting time test of cement slurry, and the setting time index of each group of cement slurry was obtained, and the time index included initial setting time index and final The index of setting time, in which the dispersion coefficient of setting time is c _νt (the ratio of the standard deviation σ of the setting time of cement slurry to the average value u), which is divided into the dispersion coefficient of initial setting time (the ratio of the standard deviation of the initial setting time of the cement paste to the average value of the initial setting time) and the dispersion coefficient of the final setting time (the ratio of the standard deviation of final setting time of cement paste to the average value of final setting time);

The non-alkali liquid quick-setting agent is applied to five kinds of test cement varieties with the dosage of 4% to carry out the cement mortar strength test, and the strength index of each group of cement mortar is obtained, and the strength index includes 1d (one day) strength index and 28d ( 28 days) intensity ratio indicator. The dispersion coefficient c _νs of the 1d strength index is the ratio of the standard deviation of the 1d strength of the mortar to the average u of the 1d strength of the mortar, and the dispersion coefficient of the 28d strength ratio index It is the ratio of the standard deviation of the mortar 28d strength ratio to the average value of the mortar 28d strength ratio.

Then the cement variety adaptability coefficient is The coefficient is a dimensionless index, and the standard value of the adaptability coefficient is 0.8 after a large amount of test data under the condition of meeting the requirements of the specification. When it is less than this value, it means that the liquid quick-setting agent has good adaptability to different cements and can meet the adaptability to different cement varieties; The adaptability of a certain brand of cement varieties cannot meet the relevant requirements when it is applied to other brands of cement varieties.

The test cement varieties are commercially available benchmark cement, Shanshui cement, conch cement, lion head cement and Three Gorges cement. in,

Benchmark cement: produced by China Academy of Building Materials Science;

Shanshui cement: produced by Shandong Shanshui Cement Group Co., Ltd.;

Conch Cement: produced by Anhui Conch Cement Co., Ltd.;

Lion Head Cement: produced by Taiyuan Lion Head Cement Co., Ltd.;

Three Gorges Cement: Produced by Gezhouba Group Cement Co., Ltd.

The early high-strength composite alkali-free liquid accelerator provided in the examples of this application can improve the coagulation accelerator effect of the accelerator to a certain extent by adding activated aluminum hydroxide, and the activated aluminum hydroxide is in the solution, which can easily release aluminum ions . And activated aluminum hydroxide is non-toxic and harmless, relatively stable, not easy to deliquescence, and has no corrosive effect on steel bars.

Detailed ways

The early high-strength composite alkali-free liquid quick-setting agent of the embodiment of the present application, the preparation method and the application in shotcrete construction are described in detail below.

As mentioned in the background art, in the prior art, aluminum hydroxide is used as a common liquid quick-setting agent. The aluminum sulfate-type liquid quick-setting agent is added with aluminum hydroxide component. Since aluminum hydroxide is an amphoteric compound, its solubility in the solution is very small. ion). Therefore, the addition of aluminum hydroxide has little or no improvement in the accelerating effect of the accelerator. And when a certain amount of aluminum hydroxide is added, when the saturation solubility is reached, no matter how much aluminum hydroxide is added, the coagulation-accelerating effect cannot be improved, resulting in too long initial setting time, which is not conducive to the construction of shotcrete, and it is easy to slump, reducing the cost of a shotcrete. Layer thickness affects construction efficiency.

In view of the above-mentioned defects of the prior art, the first aspect of the embodiment of the present application provides an early high-strength composite alkali-free liquid accelerator.

The non-alkali liquid quick-setting agent comprises the following components by weight:

Aluminum sulfate 45% to 55%;

Activated aluminum hydroxide 5% to 10%;

Fluoride salt 5% to 10%;

Alcoholamine 1.5%~4%;

Polyacrylamide 0.5% ~ 1%;

Organic water reducer 1% to 3%;

Stabilizer 0.8% ~ 1%;

Water 25%～35%.

In the non-alkali liquid quick-setting agent provided in the embodiment of the present application, the fluoride salt is selected from one or more of sodium fluoride, potassium fluoride, and magnesium fluoride. Fluoride ions and sulfate ions in fluoride salts react with calcium ions, consume a large amount of calcium ions, and the silicon-rich layer formed by the surface hydrolysis of C ₃ S (tricalcium silicate) is difficult to form a double electron layer, and the generated CSH (water Calcium silicate) has a small C/S (calcium-silicon ratio Ca/Si) value, and water can continuously diffuse through CSH to C ₃ S, so that the induction period of C ₃ S disappears, thereby promoting the hydration of C ₃ S . At the same time, due to the large amount of heat of hydration released by the above reaction, the hydration reaction of each component in the cement is promoted to form a large amount of calcium silicate gel, thereby improving the setting accelerator effect of the accelerator.

In addition, the non-alkali liquid quick-setting agent provided by the embodiment of the present application is mixed with activated aluminum hydroxide, which can improve the setting accelerator effect of the quick-setting agent to a certain extent, and the activated aluminum hydroxide is in the solution, which can easily release aluminum ions come out. However, when the dosage of activated aluminum hydroxide exceeds a certain dosage, the effect of accelerating the setting is not significantly improved, and the effect of accelerating the setting of the accelerator is weakened.

If it is simply replaced with activated aluminum hydroxide, the effect of accelerating the setting agent on the accelerator will be weakened after the dosage reaches a certain amount. Therefore, adding fluoride salt components, the fluoride ions in the solution can further promote the dissolution of active aluminum hydroxide and aluminum sulfate, and through the synergistic effect with aluminum sulfate and active aluminum hydroxide, the synergistic effect can effectively improve the quick-setting agent. Accelerated setting effect, reducing the amount of accelerator (3-5%), shortening the setting time (the initial setting time can be controlled at about 2 minutes, and the final setting time is within 6 minutes), which is beneficial to the construction of shotcrete, and it is not easy to slump. Increase the thickness of the first spray layer, improve the construction efficiency, and significantly enhance the effect of the accelerator.

In the non-alkali liquid quick-setting agent provided in the embodiment of the present application, the alcohol amine includes triethanolamine, and the weight portion of the triethanolamine is 0.5% to 1%, and the alcohol amine includes diethanolamine. The weight of the diethanolamine The portion is 1% to 3%. Among them, the early strength effect of triethanolamine is to promote the hydration of C ₃ A (3CaO·Al ₂ O ₃ ), and accelerate the formation of ettringite. There is a pair of unshared electrons in the triethanolamine molecule, which is easy to form covalent bonds with metal ions to form a stable complex. The complex forms many soluble regions in the solution, which improves the diffusion rate of hydration products and shortens the cement Incubation period in the hydration process, thus improving early strength.

In the non-alkali liquid quick-setting agent provided in the examples of the present application, the organic water reducer is polyethylene glycol polycondensate. Polyethylene glycol polycondensate is an organic water-reducing component, which can exist stably. The addition of activated aluminum hydroxide and polyethylene glycol polycondensate can increase the content of aluminum ions in the accelerator, and can effectively improve the concrete Early strength and late strength, the latter strength is almost not lost, and even increased to a certain extent, thus significantly improving the strength performance of the liquid accelerator for shotcrete. Several other water-reducers were tested, such as melamine-type water-reducers, polycarboxylate-type water-reducers, naphthalene-based high-efficiency water-reducers, etc., but they did not have corresponding effects after being mixed in, or could not exist stably in the solution. .

In the non-alkali liquid quick-setting agent provided in the embodiment of the present application, the stabilizer is hydrated magnesium silicate. For the liquid water reducing agent added with active aluminum hydroxide and polyethylene glycol polycondensate, if other stabilizers are used instead of hydrated magnesium silicate, the liquid accelerator cannot achieve a more ideal effect.

The second aspect of the embodiment of the present application provides a method for preparing an early high-strength composite alkali-free liquid accelerator, comprising the following steps:

① First weigh a certain amount of water, add sodium fluoride into the water at room temperature, stir rapidly for 10-30 minutes, then add diethanolamine, and continue stirring for 10-20 minutes to obtain sodium fluoride solution;

②When the sodium fluoride solution is heated to 60-70°C, add aluminum sulfate and activated aluminum hydroxide several times, perform high-speed shear stirring at 500-800rpm/min, then add stabilizer, and control the temperature at about 70°C. The stirring time is 90-150 minutes, and the mother liquor of the non-alkali quick-setting agent is initially obtained;

③Compound the mother liquor of alkali-free quick-setting agent, add triethanolamine, polyacrylamide and organic water reducer, control the temperature at 40-60°C, stir at 300-500rpm/min, and react at 60-90min. After filtering, the described early-high-strength composite non-alkali liquid quick-setting agent can be obtained.

The early high-strength composite non-alkali liquid quick-setting agent of the embodiment of the application has the following positive effects:

1. Good coagulation promoting effect. In accordance with the requirements of GB/T35159-2017 "Accelerator for Shotcrete" standard, the cement paste test was carried out. The alkali-free liquid accelerator has an initial setting effect at a relatively low dosage (3% to 5% of the cement mass). The time is about 2 minutes, and the final setting time is within 6 minutes.

2. High early strength and late strength. According to the requirements of GB/T35159-2017 "Accelerators for Shotcrete", the cement mortar test was carried out, and the strength was determined to be about 15MPa in 1 day, and the compressive strength ratio reached or exceeded 100% in 28 days.

3. Good stability. The non-alkali liquid quick-setting agent can keep the high concentration of the solution above 65%, without precipitation and crystallization.

4. Good adaptability. The alkali-free liquid accelerator has good adaptability to cements of different origins and brands.

5. During the construction process, it can effectively reduce the amount of rebound and dust of shotcrete, effectively improve the support effect and control the deformation of surrounding rock.

Embodiments of the present invention are described below through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various modifications or changes can be made to the details in this specification based on different viewpoints and applications without departing from the spirit of the present invention.

In the following examples, the reagents, materials and instruments used are commercially available unless otherwise specified.

Example 1

The components of the early high-strength composite alkali-free liquid quick-setting agent are based on mass percentage: 50% aluminum sulfate, 10% active aluminum hydroxide, 8% sodium fluoride, 2% diethanolamine, 1% triethanolamine, 0.5% polyacrylamide, Organic water reducer 2%, stabilizer 0.8%, water 25.7%.

The specific preparation method of early high-strength compound alkali-free liquid accelerator is as follows:

① First weigh 25.7% of water, add sodium fluoride to water at room temperature, stir rapidly for 20 minutes, then add diethanolamine, and continue stirring for 10 minutes to obtain sodium fluoride solution;

②When the sodium fluoride solution is heated to 60°C, add aluminum sulfate and activated aluminum hydroxide several times, perform high-speed shear stirring at 600rpm/min, then add stabilizer, control the temperature at 70°C, and stir for 120min. Initially obtain the mother liquor of alkali-free accelerator;

③Compound the mother liquor of alkali-free quick-setting agent, add triethanolamine, polyacrylamide and organic water reducer, control the temperature at 40°C, stir at 500rpm/min, and react for 60min. After filtration, the described Early high-strength composite non-alkali liquid accelerator.

Example 2

The components of Zaogao-strength composite alkali-free liquid accelerator are by mass percentage: 45% aluminum sulfate, 10% active aluminum hydroxide, 10% sodium fluoride, 1% diethanolamine, 1% triethanolamine, 1% polyacrylamide, Organic water reducer 2%, stabilizer 1%, water 29%.

The specific preparation method of early high-strength compound alkali-free liquid accelerator is as follows:

① First weigh 29% of water, add sodium fluoride into water at room temperature, stir rapidly for 30 minutes, then add diethanolamine, and continue stirring for 10 minutes to obtain sodium fluoride solution;

②When the sodium fluoride solution is heated to 60°C, add aluminum sulfate and activated aluminum hydroxide several times, perform high-speed shear stirring at 800rpm/min, then add stabilizer, control the temperature at 75°C, and stir for 150min. Initially obtain the mother liquor of alkali-free accelerator;

③Compound the mother liquor of alkali-free quick-setting agent, add triethanolamine, polyacrylamide and organic water reducer, control the temperature at 50°C, stir at 400rpm/min, and react for 75min. After filtration, the described Early high-strength composite non-alkali liquid accelerator.

Example 3

The components of the early high-strength composite alkali-free liquid quick-setting agent are based on mass percentage: 55% aluminum sulfate, 5% active aluminum hydroxide, 5% sodium fluoride, 2% diethanolamine, 1% triethanolamine, 0.5% polyacrylamide, Organic water reducer 1.5%, stabilizer 0.8%, water 29.2%.

The specific preparation method of early high-strength compound alkali-free liquid accelerator is as follows:

① First weigh 29.2% water, add sodium fluoride to the water at room temperature, stir rapidly for 15 minutes, then add diethanolamine, and continue stirring for 15 minutes to obtain sodium fluoride solution;

②When the sodium fluoride solution is heated to 65°C, add aluminum sulfate and activated aluminum hydroxide several times, perform high-speed shear stirring at 600rpm/min, then add stabilizer, control the temperature at 70°C, and stir for 120min. Initially obtain the mother liquor of alkali-free accelerator;

③Compound the mother liquor of alkali-free quick-setting agent, add triethanolamine, polyacrylamide and organic water reducer, control the temperature at 45°C, stir at 400rpm/min, and react for 80min. After filtering, the described Early high-strength composite non-alkali liquid accelerator.

Example 4

The components of Zaogao-strength composite alkali-free liquid quick-setting agent are by mass percentage: 45% aluminum sulfate, 8% active aluminum hydroxide, 7% sodium fluoride, 1.5% diethanolamine, 1% triethanolamine, 1% polyacrylamide, Organic water reducer 3%, stabilizer 0.8%, water 32.7%.

The specific preparation method of early high-strength compound alkali-free liquid accelerator is as follows:

① First weigh 32.7% of water, add sodium fluoride into water at room temperature, stir rapidly for 15 minutes, then add diethanolamine, and continue stirring for 15 minutes to obtain sodium fluoride solution;

②When the sodium fluoride solution is heated to 65°C, add aluminum sulfate and activated aluminum hydroxide several times, perform high-speed shear stirring at 600rpm/min, then add stabilizer, control the temperature at 70°C, and stir for 120min. Initially obtain the mother liquor of alkali-free accelerator;

③Compound the mother liquor of alkali-free quick-setting agent, add triethanolamine, polyacrylamide and organic water reducer, control the temperature at 45°C, stir at 400rpm/min, and react for 80min. After filtering, the described Early high-strength composite non-alkali liquid accelerator.

Example 5

The components of the early high-strength composite alkali-free liquid quick-setting agent are based on mass percentage: 50% aluminum sulfate, 5% active aluminum hydroxide, 7% sodium fluoride, 2% diethanolamine, 0.5% triethanolamine, 0.5% polyacrylamide, Organic water reducer 2.5%, stabilizer 1%, water 31.5%.

The specific preparation method of early high-strength compound alkali-free liquid accelerator is as follows:

① First weigh 31.5% of water, add sodium fluoride into the water at room temperature, stir rapidly for 15 minutes, then add diethanolamine, and continue stirring for 10 minutes to obtain sodium fluoride solution;

②When the sodium fluoride solution is heated to 60°C, add aluminum sulfate and activated aluminum hydroxide several times, perform high-speed shear stirring at 500rpm/min, then add stabilizer, control the temperature at 70°C, and stir for 150min. Initially obtain the mother liquor of alkali-free accelerator;

③Compound the mother liquor of alkali-free quick-setting agent, add triethanolamine, polyacrylamide and organic water reducer, control the temperature at 45°C, stir at 300rpm/min, and react for 90min. After filtration, the described Early high-strength composite non-alkali liquid accelerator.

Comparative example 6

The proportion of accelerator is: 55% of aluminum sulfate, 5% of aluminum hydroxide, 2% of diethanolamine, 0.5% of triethanolamine, 0.5% of polyacrylamide, 1% of stabilizer, and 36% of water.

Comparative example 7

The proportion of accelerator is: 55% of aluminum sulfate, 8% of sodium fluoride, 1% of diethanolamine, 0.5% of triethanolamine, 0.5% of polyacrylamide, 1% of stabilizer, and 34% of water.

Comparative example 8

Commercially available non-alkali liquid accelerator: BASF Haoke Mining Chemical (China) Co., Ltd., non-alkali liquid accelerator, Meigu SA160, obtained through experiments, the dosage is 6% to 10%, the initial setting time is 3 minutes, the final setting time is about 10 minutes, and the 28-day strength retention rate is 87%.

The present invention has all obtained satisfactory technical effect through test and probation, and effective test data is as follows:

According to the requirements of GB/T35159-2017 "Accelerators for Shotcrete", the test of the setting time of the cement paste and the compressive strength of the cement mortar was carried out. Wherein, the dosage of the liquid quick-setting agent is calculated according to the percentage of cement weight, and the liquid quick-setting agent used is the product prepared in Examples 1 to 5, 6 to 7 are comparative quick-setting agents, and 8 is a commercially available alkali-free liquid quick-setting agent. agent.

Determination of setting time of cement slurry:

Cement 400g

140g of water (the water content in the liquid accelerator should be subtracted)

Determination of compressive strength of cement mortar:

Cement 900g

Standard sand 1350g

450g of water

The test results are shown in Table 1:

The application effect of this alkali-free liquid quick-setting agent of table 1

It can be seen from Table 1 that all the indicators of the alkali-free liquid accelerator meet the requirements of the GB/T35159-2017 "Accelerator for Shotcrete" specification, the setting time is fast, and it can effectively improve the early strength of mortar, and the later strength is basically no loss.

In order to verify the adaptability of the alkali-free liquid accelerator to different cements, five kinds of cements commonly used in engineering were selected, and the setting time and mortar strength were measured respectively. The test results are shown in Table 2. Sample 1 is selected as the accelerator, and the cements are benchmark cement, Shanshui cement, conch cement, lion head cement and Three Gorges cement.

Table 2 The application effect of the quick-setting agent on different cements

It can be seen from Table 2 that, for these five types of cement, the quick-setting agent meets the requirements in the specification. After calculation, the adaptability coefficient of the alkali-free liquid accelerator to different cements is 0.3, which is less than the standard value of 0.8, indicating that the adaptability to the five kinds of cement is better. Since these cements are representative to a certain extent and are widely used in field engineering, it can be seen that the quick-setting agent has good adaptability to different cements.

Table 3 Comparative Examples 6, 7, 8 Accelerated Effects of Application Effects on Different Cement

The liquid quick-setting agents of Comparative Examples 6, 7, and 8 are selected in Table 3, and are all mixed into these 5 different cements according to their respective optimal dosages, which can be obtained from the data in the table. On the one hand, adopt the Liquid quick-setting agent, its dosage will be greater than the liquid quick-setting agent dosage of the embodiment of the application, and its setting time is longer than the setting time of the embodiment of the application, and its mortar strength is lower than the mortar strength of the embodiment of the application; On the one hand, the adaptability coefficient of contrast 6 accelerator to different cements is 1.3, the adaptability coefficient of contrast 7 accelerator to different cements is 1.45, and the adaptability coefficient of contrast 8 accelerator to different cements is 1.31, all of which are greater than the standard value of 0.8 . It shows that these accelerators have poor adaptability to different types of cement.

The above description is only a preferred embodiment of the present application and an illustration of the applied technical principle. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solution formed by the specific combination of the above-mentioned technical features, but should also cover the technical solution formed by the above-mentioned technical features without departing from the inventive concept. Other technical solutions formed by any combination of or equivalent features thereof. For example, a technical solution formed by replacing the above-mentioned features with technical features with similar functions disclosed in this application (but not limited to).

Claims (10)

1. An early high-strength composite alkali-free liquid accelerator is characterized in that: the alkali-free liquid accelerator comprises the following components in parts by weight:

45 to 55 percent of aluminum sulfate;

5 to 10 percent of active aluminum hydroxide;

5 to 10 percent of fluoride salt;

1.5 to 4 percent of alcohol amine;

0.5 to 1 percent of polyacrylamide;

1-3% of organic water reducing agent;

0.8 to 1 percent of stabilizer;

25 to 35 percent of water.

2. The early high strength composite alkali-free liquid accelerator as claimed in claim 1, wherein: the fluoride salt is selected from one or more of sodium fluoride, potassium fluoride and magnesium fluoride.

3. The early high strength composite alkali-free liquid accelerator as claimed in claim 1, wherein: the alcohol amine is selected from one or more of diethanolamine, triethanolamine, monoethanolamine, dimethylethanolamine, diethylethanolamine, methyldiethanolamine and ethyldiethanolamine.

4. The early high strength composite alkali-free liquid accelerator as claimed in claim 3, wherein: the triethanolamine comprises 0.5 to 1 weight percent of triethanolamine.

5. The early high-strength composite alkali-free liquid accelerator as claimed in claim 3 or 4, wherein: the alcohol amine comprises 1-3% of diethanolamine by weight.

6. The early high strength composite alkali-free liquid accelerator as claimed in claim 1, wherein: the organic water reducing agent is polyethylene glycol polycondensate.

7. The early high strength composite alkali-free liquid accelerator as claimed in claim 1, wherein: the stabilizing agent is hydrous magnesium silicate.

8. A method for preparing the early high strength composite alkali-free liquid accelerator according to any one of claims 1 to 7, comprising the steps of:

step 1: mixing fluoride salt, diethanolamine and water to obtain fluoride salt solution;

step 2: heating the fluoride solution to 60-70 ℃, adding aluminum sulfate, active aluminum hydroxide and a stabilizer, and stirring at a high speed to obtain an alkali-free accelerator mother liquor;

and step 3: and adding alcohol amine, polyacrylamide and an organic water reducing agent into the alkali-free accelerator mother liquor, controlling the temperature to be 40-60 ℃, and filtering to obtain the early high-strength composite alkali-free liquid accelerator.

9. The method for preparing the early high-strength composite alkali-free liquid accelerator as claimed in claim 8, further comprising one or more of the following technical characteristics:

A1) in the step 1, sodium fluoride is added into water at normal temperature, the mixture is rapidly stirred for 10-30 min, then diethanolamine is added, and the stirring is continued for 10-20 min, so that a sodium fluoride solution is obtained;

A2) in the step 2, when the sodium fluoride solution is heated to 60-70 ℃, aluminum sulfate and active aluminum hydroxide are added for multiple times, high-speed shearing stirring is carried out at 500-800 rpm/min, then a stabilizer is added, the temperature is controlled to be about 70 ℃, the stirring time is 90-150 min, and an alkali-free accelerator mother liquor is obtained preliminarily;

A3) and 3, compounding the alkali-free accelerator mother liquor, adding triethanolamine, polyacrylamide and an organic water reducing agent, controlling the temperature at 40-60 ℃, stirring at 300-500 rpm/min, and reacting for 60-90 min, and filtering to obtain the early high-strength composite alkali-free liquid accelerator.

10. A shotcrete, comprising: the sprayed concrete comprises the early high-strength composite alkali-free liquid accelerator as defined in any one of claims 1-7, wherein the mixing amount of the alkali-free liquid accelerator is 3-5% of the mass of cement in the sprayed concrete;

cement variety adaptation coefficient c of alkali-free liquid accelerator_aLess than 0.8 of the total weight of the composition,

the method for testing the cement variety adaptive coefficient comprises the following steps:

applying the alkali-free liquid accelerator to five test cement varieties in a mixing amount of 4%, and acquiring the dispersion coefficient of each subentry index aiming at different cement varieties, wherein the subentry indexes comprise an initial setting time index, a final setting time index, a 1d strength index and a 28d strength ratio index, and the adaptive coefficient c_aIs the sum of the discrete coefficients of each of the fractional indicators.