CN113511860B - A kind of emulsified asphalt modified low-resilience shotcrete and preparation method thereof - Google Patents

Abstract

The invention discloses emulsified asphalt modified low-resilience shotcrete which comprises the following raw material components in parts by weight: 435 parts of cement, 70-100 parts of emulsified asphalt, 175-215 parts of water, 787.5-1050 parts of river sand, 700-962.5 parts of limestone, 35 parts of an accelerator and 24-40 parts of a mineral admixture. The preparation method of the low-resilience shotcrete comprises the steps of mixing and sieving river sand and limestone, adding cement, mixing, adding water, stirring and mixing uniformly, adding emulsified asphalt, quickly stirring and reacting at the stirring speed of 120-150 r/min, adding a mineral admixture and/or high-strength high-modulus fiber and an accelerating agent, and mixing for use. The shotcrete prepared by the method has the characteristic of low rebound rate, and can reduce material waste and improve construction efficiency when being used for supporting construction of tunnels and underground projects.

Description

A kind of emulsified asphalt modified low-resilience shotcrete and preparation method thereof

technical field

The invention belongs to the technical field of concrete materials, in particular to a low-resilience shotcrete modified by emulsified asphalt and a preparation method thereof.

Background technique

Shotcrete is one of the main forms of tunnel and underground engineering support. With the further development of infrastructure, the amount of shotcrete increases sharply with the increase of engineering projects. At the same time, in the existing shotcrete construction in my country, due to the The ratio is unreasonable, the control parameters of the sprayer are not clear, the rebound rate is too large during the spraying process, resulting in a lot of waste of materials, affecting the quality of shotcrete, and causing certain safety hazards to the sprayer, and also causing unnecessary material circulation transportation. , which not only affects the construction efficiency, but also causes great pressure on the environment due to material waste. With the continuous expansion of the use of shotcrete in support and reinforcement projects, the quality of shotcrete will be further improved and the rebound rate during shotcrete construction will be reduced. Especially under the existing technical equipment and management level of highway tunnels in my country, The research on low-rebound shotcrete technology has practical significance.

There are three factors that affect the rebound rate of shotcrete: (1) From the perspective of raw materials, measures such as adding admixtures, adding fibers, increasing the fineness of admixtures, and reducing the maximum particle size of aggregates can reduce the amount of concrete in the concrete. Dispersion during jet transmission, reducing rebound rate. (2) From the perspective of mixing ratio, measures such as increasing the amount of cementitious materials, improving the consistency of concrete, and adjusting the appropriate slump and setting time can improve the adhesion efficiency of shotcrete and reduce the rebound rate. (3) From the perspective of construction technology, measures such as appropriately increasing the thickness of the primary injection, taking the right angle as the injection angle, and controlling the working wind pressure reasonably can significantly reduce the rebound rate.

At present, researchers at home and abroad have done a lot of research on reducing the rebound rate of shotcrete, but less research from the perspective of material modification. Therefore, it is urgent to modify ordinary shotcrete materials to solve the problems of high rebound rate of shotcrete and poor impermeability of concrete, improve the performance of tunnel lining concrete, reduce the waste of raw materials, ensure the health of construction workers, and improve the social economy. effect.

SUMMARY OF THE INVENTION

In view of the above deficiencies, the present invention discloses a low-resilience shotcrete modified by emulsified asphalt and a preparation method thereof.

The present invention adopts following technical scheme to realize:

A low-resilience shotcrete modified by emulsified asphalt, comprising the following raw material components in parts by weight: 435 parts of cement, 70 to 100 parts of emulsified asphalt, 175 to 215 parts of water, 787.5 to 1050 parts of river sand, and 700 parts of limestone. ~962.5 parts, 35 parts of accelerator, 24-40 parts of mineral admixture; the cement is Portland cement of P.O42.5, the emulsified asphalt is anionic emulsified asphalt, and the accelerator is One or two combinations of aluminum sulfate and sodium fluoride, and the mineral admixture is one or more combinations of first-grade fly ash, micro-silica fume and ultra-fine limestone powder.

Further, the raw materials of the emulsified asphalt modified low-resilience shotcrete also include 2-6 parts by weight of high-strength and high-modulus fibers, and the high-strength and high-modulus fibers are polyvinyl alcohol fibers, One or more combinations of polypropylene fibers and PE fibers.

Further, the length of the polyvinyl alcohol fibers is 3-5 μm.

Further, the anionic emulsified asphalt is one or more combinations of sulfonate emulsified asphalt, carboxylate emulsified asphalt and sulfate emulsified asphalt.

Further, the mineral admixture is a combination of micro-silica fume and ultra-fine limestone powder, the mass ratio of the micro-silica fume and the ultra-fine limestone powder is 2:1, and the particle size of the micro-silica fume is 0.1～ 0.2 μm, and the particle size of the ultrafine limestone powder is 30-35 μm.

Further, the accelerator is a combination of aluminum sulfate and sodium fluoride, and the mass ratio of the aluminum sulfate and sodium fluoride is 5:1.

The preparation method of the above-mentioned emulsified asphalt modified low-resilience shotcrete, it comprises the following steps:

(1) Weigh each raw material component in proportion, mix river sand and limestone and sieve, the aperture of the sieve is 4.75~9.5mm, and place it in a stirring pot, then add cement and mix evenly, add water at the stirring speed. Stir for 2 minutes at a temperature of 60-80 r/min, then add emulsified asphalt and rapidly stir for 3 minutes at a stirring speed of 120-150 r/min, and finally add mineral admixtures and/or high-strength and high-modulus fibers. Under the condition of 120～150r/min, stir rapidly for 1.5min to obtain mixture A;

(2) Pour out the mixture A obtained in step (1) from the stirring pot, and pour it into the hopper of the wet spraying machine, and then pour the accelerator into the accelerator tube, then start the machine, and the mixture A passes through the pressure. The slurry is pumped to the nozzle of the jet machine and fused with the accelerator, and then sprayed with compressed air.

The present invention uses emulsified asphalt to modify the shotcrete. At the initial stage of the reaction, due to the electrostatic attraction and van der Waals force between the cement particles and the asphalt particles, the asphalt particles will aggregate on the surface of the cement particles, and most of these asphalt particles are on the cement particles. A flocculent structure is formed nearby; with the progress of cement hydration and emulsified asphalt demulsification, the asphalt particles will gradually adsorb to the surface of the cement particles; after the emulsified asphalt is completely demulsified, the asphalt-water interfacial tension in the system gradually increases to the asphalt- The interfacial tension of the cement transitions, and the asphalt particles recover their cohesive force, so that they can adhere to the surrounding cement particles, thereby increasing the cohesive force and reducing the rebound rate of shotcrete.

At the same time, because concrete belongs to a continuous particle accumulation system, the strength is exerted by cementing materials to bond aggregates of various particle sizes together. During the hardening process of concrete, voids will inevitably occur, which will affect the compressive strength of concrete. Therefore, in the present invention, secondary particles such as micro-silica fume and ultra-fine limestone powder are added, thereby reducing the void ratio in the concrete, making the concrete structure more compact, and improving the strength of the concrete to a certain extent, and the micro-silica fume has a high Strong pozzolanic effect, it can undergo secondary hydration reaction with cement hydration product calcium hydroxide to form a gel product, fill the cement stone structure, and improve the mechanical properties of concrete; while ultra-fine limestone powder can promote the hydration reaction of cement, and it can interact with cement. The aluminum-containing minerals react to form calcium carbonate aluminate, which has a certain contribution to the development of concrete strength.

In the present invention, high-strength and high-modulus fibers are added, because in the initial stage of the shotcrete under load, the cement base and the fibers bear the external force together, and the former is the main bearer of the external force; when the base material cracks, the fibers across the crack become the external force the main recipient. In the process of concrete hardening, fibers can change the internal structure of concrete, reduce the number and size of plastic cracks and internal micro-cracks in concrete, and improve the continuity of the concrete material medium, thereby improving the comprehensive performance of concrete. During the force process, the fibers change the stress field of the concrete matrix, thereby improving the mechanical properties of the concrete.

Compared with the prior art, this technical solution has the following beneficial effects:

The invention adopts emulsified asphalt as the modified material, and prepares a shotcrete material with low rebound rate through physical blending. In the lining support project of the present invention, it can be effectively bonded to the tunnel wall, reducing the rebound rate of the shotcrete and increasing the impermeability, thereby effectively improving its protection ability to the structure. The method is simple, the operation is convenient, and it is suitable for the construction of supporting projects such as various tunnels and underground works.

Detailed ways

The following examples further illustrate the present invention, but are not intended to limit the present invention. The unremarked specific experimental conditions and methods in the following examples, the adopted technical means are usually conventional means well known to those skilled in the art.

Example 1:

A low-resilience shotcrete modified by emulsified asphalt, comprising the following raw material components in parts by weight: 435 parts of cement, 100 parts of emulsified asphalt, 175 parts of water, 787.5 parts of river sand, 962.5 parts of limestone, and 35 parts of accelerators. parts, 30 parts of mineral admixtures, and 5 parts of high-strength and high-modulus fibers; the cement is Portland cement of P.O42.5, the emulsified asphalt is sodium lauryl sulfate emulsified asphalt, and the speed The coagulant is sodium fluoride, the mineral admixture is micro-silica fume, and the particle size of the micro-silica fume is 0.1-0.2 μm; the high-strength and high-modulus fibers are polyvinyl alcohol fibers, and polyvinyl alcohol The fiber length is 3 μm-5 μm.

The preparation method of the emulsified asphalt modified low-resilience shotcrete described in the present embodiment comprises the following steps:

(1) Weigh each raw material component in proportion, mix river sand and limestone through a sieve, the aperture of the sieve is 4.75mm, and place it in a stirring pot, then add cement and mix evenly, add water at a stirring speed of 60r Stir for 2 minutes under the condition of /min, then add the emulsified asphalt, and then stir quickly for 3 minutes at a stirring speed of 120r/min. Finally, add mineral admixtures and high-strength and high-modulus fibers and stir at a speed of 120r/min. 1.5min to obtain mixture A;

(2) Pour out the mixture A obtained in step (1) from the stirring pot, and pour it into the hopper of the wet spraying machine, and then pour the accelerator into the accelerator tube, then start the machine, and the mixture A passes through the pressure. The slurry is pumped to the nozzle of the jet machine and fused with the accelerator, and then sprayed with compressed air.

Example 2:

A low-resilience shotcrete modified by emulsified asphalt, comprising the following raw material components in parts by weight: 435 parts of cement, 75 parts of emulsified asphalt, 215 parts of water, 787.5 parts of river sand, 962.5 parts of limestone, and 35 parts of accelerator. 30 parts of mineral admixtures; the cement is Portland cement of P.O42.5, the accelerator is aluminum sulfate, the emulsified asphalt is sodium lauryl sulfate emulsified asphalt, and the mineral The admixture is first-grade fly ash.

The preparation method of the emulsified asphalt modified low-resilience shotcrete described in the present embodiment comprises the following steps:

(1) Weigh each raw material component in proportion, mix river sand and limestone through a sieve, the aperture of the sieve is 5.5mm, and place it in a stirring pot, then add cement and mix evenly, add water at a stirring speed of 70r Stir for 2 min under the condition of /min, then add the emulsified asphalt and rapidly stir for 3 min under the condition of a stirring speed of 130 r/min, finally add mineral admixtures and stir rapidly for 1.5 min under the condition of 120 r/min to obtain mixture A;

(2) Pour out the mixture A obtained in step (1) from the stirring pot, and pour it into the hopper of the wet spraying machine, and then pour the accelerator into the accelerator tube, then start the machine, and the mixture A passes through the pressure. The slurry is pumped to the nozzle of the jet machine and fused with the accelerator, and then sprayed with compressed air.

Example 3:

A low-resilience shotcrete modified by emulsified asphalt, comprising the following raw material components in parts by weight: 435 parts of cement, 100 parts of emulsified asphalt, 175 parts of water, 787.5 parts of river sand, 962.5 parts of limestone, and 35 parts of accelerators. parts, 30 parts of mineral admixtures, and 3 parts of high-strength and high-modulus fibers; the cement is Portland cement of P.O42.5, the emulsified asphalt is sodium lauryl sulfate emulsified asphalt, and the speed The coagulant is aluminum sulfate, and the mineral admixture is a combination of first-grade fly ash and ultra-fine limestone powder, and the mass ratio of the first-grade fly ash and ultra-fine limestone powder is 2:1, and the ultra-fine limestone powder is in a mass ratio of 2:1. The particle size of the fine limestone powder is 30-35 μm; the high-strength and high-modulus fibers are polypropylene fibers.

The preparation method of the emulsified asphalt modified low-resilience shotcrete described in the present embodiment comprises the following steps:

(1) Weigh each raw material component in proportion, mix the river sand and limestone through a sieve, the aperture of the sieve is 7.5mm, and place it in a stirring pot, then add cement and mix evenly, add water at a stirring speed of 80r Stir for 2 minutes under the condition of /min, then add the emulsified asphalt, and then quickly stir for 3 minutes at a stirring speed of 140 r/min. Finally, add mineral admixtures and high-strength and high-modulus fibers and stir rapidly under the condition of 130 r/min. 1.5min to obtain mixture A;

(2) Pour out the mixture A obtained in step (1) from the stirring pot, and pour it into the hopper of the wet spraying machine, and then pour the accelerator into the accelerator tube, then start the machine, and the mixture A passes through the pressure. The slurry is pumped to the nozzle of the jet machine and fused with the accelerator, and then sprayed with compressed air.

Example 4:

A low-resilience shotcrete modified by emulsified asphalt, comprising the following raw material components in parts by weight: 435 parts of cement, 75 parts of emulsified asphalt, 215 parts of water, 787.5 parts of river sand, 962.5 parts of limestone, and 35 parts of accelerator. 30 parts of mineral admixtures; the cement is Portland cement of P.O42.5, the emulsified asphalt is sodium lauryl sulfate emulsified asphalt, and the accelerator is aluminum sulfate and sodium fluoride The mass ratio of the aluminum sulfate and the sodium fluoride is 5:1, the mineral admixture is ultra-fine limestone powder, and the particle size of the ultra-fine limestone powder is 30-35 μm.

The preparation method of the emulsified asphalt modified low-resilience shotcrete described in the present embodiment comprises the following steps:

(1) Weigh each raw material component in proportion, mix river sand and limestone through a sieve, the aperture of the sieve is 9.5mm, and place it in a stirring pot, then add cement and mix evenly, add water at a stirring speed of 80r Stir for 2 minutes under the condition of /min, then add emulsified asphalt, and then stir quickly for 3 minutes at a stirring speed of 150 r/min, and finally add mineral admixtures and/or high-strength and high-modulus fibers under the condition of 150 r/min Rapid stirring for 1.5min to obtain mixture A;

(2) Pour out the mixture A obtained in step (1) from the stirring pot, and pour it into the hopper of the wet spraying machine, and then pour the accelerator into the accelerator tube, then start the machine, and the mixture A passes through the pressure. The slurry is pumped to the nozzle of the jet machine and fused with the accelerator, and then sprayed with compressed air.

Example 5:

A low-resilience shotcrete modified by emulsified asphalt, comprising the following raw material components in parts by weight: 435 parts of cement, 100 parts of emulsified asphalt, 175 parts of water, 787.5 parts of river sand, 962.5 parts of limestone, and 35 parts of accelerators. parts, 30 parts of mineral admixtures, and 2 to 6 parts of high-strength and high-modulus fibers; the cement is Portland cement of P.O42.5, and the emulsified asphalt is sodium lauryl sulfate emulsified asphalt. Described quick-setting agent is the combination of aluminum sulfate and sodium fluoride, the mass ratio of described aluminum sulfate and sodium fluoride is 5: 1, described mineral admixture is the combination of micro-silica fume and ultrafine limestone powder, described The mass ratio of micro-silica fume and ultra-fine limestone powder is 2:1, the particle size of the micro-silica fume is 0.1-0.2 μm, the particle size of the ultra-fine limestone powder is 30-35 μm, the high-strength and high-modulus The fibers are polyvinyl alcohol fibers, and the polyvinyl alcohol fibers have a length of 3 μm to 5 μm.

The preparation method of the emulsified asphalt modified low-resilience shotcrete described in the present embodiment comprises the following steps:

(1) Weigh each raw material component in proportion, mix river sand and limestone through a sieve, the aperture of the sieve is 5mm, and place it in a stirring pot, then add cement and mix evenly, add water at a stirring speed of 60r/ Stir for 2 min under the condition of min, then add the emulsified asphalt, stir quickly for 3 min under the condition of stirring speed of 130 r/min, finally add mineral admixture and high-strength and high-modulus fiber, and stir rapidly for 1.5 min under the condition of 120 r/min min to obtain mixture A;

(2) Pour out the mixture A obtained in step (1) from the stirring pot, and pour it into the hopper of the wet spraying machine, and then pour the accelerator into the accelerator tube, then start the machine, and the mixture A passes through the pressure. The slurry is pumped to the nozzle of the jet machine and fused with the accelerator, and then sprayed with compressed air.

Example 6:

A low-resilience shotcrete modified by emulsified asphalt, comprising the following raw material components in parts by weight: 435 parts of cement, 75 parts of emulsified asphalt, 215 parts of water, 787.5 parts of river sand, 962.5 parts of limestone, and 35 parts of accelerator. parts, 35 parts of mineral admixtures, and 3 parts of high-strength and high-modulus fibers; the cement is Portland cement of P.O42.5, the emulsified asphalt is sodium dodecyl sulfonate emulsified asphalt, and the The accelerator is a combination of aluminum sulfate and sodium fluoride, and the mass ratio of the aluminum sulfate and sodium fluoride is 5:1. The mineral admixture is a combination of microsilica fume and ultrafine limestone powder. The mass ratio of silica fume and ultra-fine limestone powder is 2:1, the particle size of the micro silica fume is 0.1-0.2 μm, the particle size of the ultra-fine limestone powder is 30-35 μm, and the high-strength and high-modulus fibers It is a polyvinyl alcohol fiber, and the length of the polyvinyl alcohol fiber is 3 μm-5 μm.

The preparation method of the emulsified asphalt modified low-resilience shotcrete described in the present embodiment comprises the following steps:

(1) Weigh each raw material component in proportion, mix river sand and limestone through a sieve, the aperture of the sieve is 8.0mm, and place it in a stirring pot, then add cement and mix evenly, add water at a stirring speed of 70r Stir for 2 minutes under the condition of /min, then add the emulsified asphalt, and then quickly stir for 3 minutes at a stirring speed of 140 r/min. Finally, add mineral admixtures and high-strength and high-modulus fibers and stir rapidly under the condition of 130 r/min. 1.5min to obtain mixture A;

(2) Pour out the mixture A obtained in step (1) from the stirring pot, and pour it into the hopper of the wet spraying machine, and then pour the accelerator into the accelerator tube, then start the machine, and the mixture A passes through the pressure. The slurry is pumped to the nozzle of the jet machine and fused with the accelerator, and then sprayed with compressed air.

Example 7:

A low-resilience shotcrete modified by emulsified asphalt, comprising the following raw material components in parts by weight: 435 parts of cement, 70 parts of emulsified asphalt, 190 parts of water, 950 parts of river sand, 825 parts of limestone, and 35 parts of accelerator. parts, 24 parts of mineral admixtures, and 6 parts of high-strength and high-modulus fibers; the cement is Portland cement of P.O42.5, and the emulsified asphalt is sodium lauryl sulfate emulsified asphalt and dodecane An equal-quality mixed combination of sodium sulfonate emulsified asphalt, the accelerator is aluminum sulfate, the mineral admixture is an equal-quality mixed combination of first-grade fly ash and ultra-fine limestone powder, and the ultra-fine limestone The particle size of the powder is 30-35 μm; the high-strength and high-modulus fibers are polypropylene fibers.

The preparation method of the emulsified asphalt modified low-resilience shotcrete described in the present embodiment comprises the following steps:

(1) Weigh each raw material component in proportion, mix river sand and limestone and sieve, the aperture of the sieve is 6.0mm, and place it in a stirring pot, then add cement and mix evenly, add water at a stirring speed of 70r Stir for 2 minutes under the condition of /min, then add the emulsified asphalt, and then quickly stir for 3 minutes at a stirring speed of 150 r/min. Finally, add mineral admixtures and high-strength and high-modulus fibers and stir rapidly at 140 r/min. 1.5min to obtain mixture A;

(2) Pour out the mixture A obtained in step (1) from the stirring pot, and pour it into the hopper of the wet spraying machine, and then pour the accelerator into the accelerator tube, then start the machine, and the mixture A passes through the pressure. The slurry is pumped to the nozzle of the jet machine and fused with the accelerator, and then sprayed with compressed air.

Example 8:

A low-resilience shotcrete modified by emulsified asphalt, comprising the following raw material components in parts by weight: 435 parts of cement, 70 parts of emulsified asphalt, 200 parts of water, 1050 parts of river sand, 700 parts of limestone, and 35 parts of accelerator. parts, 40 parts of mineral admixtures, and 2 parts of high-strength and high-modulus fibers; the cement is Portland cement of P.O42.5, the emulsified asphalt is sodium dodecyl sulfonate emulsified asphalt, and the The accelerator is a combination of aluminum sulfate and sodium fluoride, and the mass ratio of the aluminum sulfate and sodium fluoride is 5:1. The mineral admixture is a combination of microsilica fume and ultrafine limestone powder. The mass ratio of silica fume and ultra-fine limestone powder is 2:1, the particle size of the micro-silica fume is 0.1-0.2 μm, the particle size of the ultra-fine limestone powder is 30-35 μm, and the high-strength and high-modulus fibers It is an equal quality combination of polyvinyl alcohol fibers and polypropylene fibers, and the length of the polyvinyl alcohol fibers is 3-5 μm.

The preparation method of the emulsified asphalt modified low-resilience shotcrete described in the present embodiment comprises the following steps:

(1) Weigh each raw material component in proportion, mix river sand and limestone through a sieve, the aperture of the sieve is 6.5mm, and place it in a stirring pot, then add cement and mix evenly, add water at a stirring speed of 80r Stir for 2 minutes under the condition of /min, then add the emulsified asphalt, and then stir quickly for 3 minutes at a stirring speed of 120r/min. Finally, add mineral admixtures and high-strength and high-modulus fibers and stir at a speed of 120r/min. 1.5min to obtain mixture A;

(2) Pour out the mixture A obtained in step (1) from the stirring pot, and pour it into the hopper of the wet spraying machine, and then pour the accelerator into the accelerator tube, then start the machine, and the mixture A passes through the pressure. The slurry is pumped to the nozzle of the jet machine and fused with the accelerator, and then sprayed with compressed air.

Example 9:

A low-resilience shotcrete modified by emulsified asphalt, comprising the following raw material components in parts by weight: 435 parts of cement, 85 parts of emulsified asphalt, 195 parts of water, 850 parts of river sand, 880 parts of limestone, and 35 parts of accelerator. parts, 35 parts of mineral admixtures, and 4 parts of high-strength and high-modulus fibers; the cement is Portland cement of P.O42.5, the emulsified asphalt is sodium lauryl sulfate emulsified asphalt, and the speed The coagulant is a combination of aluminum sulfate and sodium fluoride, and the mass ratio of the aluminum sulfate and sodium fluoride is 5:1, and the mineral admixture is a combination of microsilica fume and ultrafine limestone powder. The mass ratio of ash and ultra-fine limestone powder is 2:1, the particle size of the micro silica fume is 0.1-0.2 μm, the particle size of the ultra-fine limestone powder is 30-35 μm, and the high-strength and high-modulus fibers are Polyvinyl alcohol fiber, the length of the polyvinyl alcohol fiber is 3 μm-5 μm.

The preparation method of the emulsified asphalt modified low-resilience shotcrete described in the present embodiment comprises the following steps:

(1) Weigh each raw material component in proportion, mix river sand and limestone through a sieve, the aperture of the sieve is 5.5mm, and place it in a stirring pot, then add cement and mix evenly, add water at a stirring speed of 60r Stir for 2 minutes under the condition of /min, then add the emulsified asphalt, and then quickly stir for 3 minutes at a stirring speed of 130r/min. Finally, add mineral admixtures and high-strength and high-modulus fibers and stir at a speed of 130r/min. 1.5min to obtain mixture A;

(2) Pour out the mixture A obtained in step (1) from the stirring pot, and pour it into the hopper of the wet spraying machine, and then pour the accelerator into the accelerator tube, then start the machine, and the mixture A passes through the pressure. The slurry is pumped to the nozzle of the jet machine and fused with the accelerator, and then sprayed with compressed air.

Comparative Example 1:

A shotcrete, comprising the following raw material components in parts by weight: 435 parts of cement, 200 parts of water, 850 parts of river sand, 820 parts of limestone, 35 parts of accelerators, and 4 parts of high-strength and high-modulus fibers; The cement is Portland cement of P.O42.5, the quick-setting agent is an equal-quality mixed combination of aluminum sulfate and sodium fluoride, and the high-strength and high-modulus fibers are polypropylene fibers.

The preparation method of the shotcrete described in this comparative example is the same as the preparation method of the emulsified asphalt modified low-resilience shotcrete described in Example 1.

Experimental example:

The shotcrete prepared by the methods described in Examples 1 to 9 and Comparative Example 1 was tested for 28d compressive strength and rebound rate. The test results are shown in Table 1.

Table 1 Test results of 28d compressive strength and rebound rate of shotcrete

It can be seen from Table 1 that adding mineral admixtures and emulsified asphalt according to the method of the present invention can improve the compressive strength of shotcrete and reduce the rebound rate. When the mineral admixture is mixed with micro-silica fume and ultra-fine limestone powder, the compressive strength and resilience of the resulting shotcrete are obviously better than those of first-grade fly ash, micro-silica fume or ultra-fine limestone powder and a The mixed combination of high-grade fly ash and ultra-fine limestone powder; and the addition of high-strength and high-modulus fibers can effectively improve the compressive strength of shotcrete.

In addition, it should be understood that although this specification is described in terms of embodiments, not each embodiment only includes an independent technical solution, and this description in the specification is only for the sake of clarity, and those skilled in the art should take the specification as a whole , the technical solutions in each embodiment can also be appropriately combined to form other implementations that can be understood by those skilled in the art.

Claims (7)

1. a low-resilience shotcrete modified by emulsified asphalt, is characterized in that: comprise the raw material components of following parts by weight: 435 parts of cement, 70～100 parts of emulsified asphalt, 175～215 parts of water, 787.5～100 parts of river sand 1050 parts, 700-962.5 parts of limestone, 35 parts of accelerators, and 24-40 parts of mineral admixtures; the cement is Portland cement of P.O42.5, and the emulsified asphalt is anionic emulsified asphalt. The quick-setting agent is one or a combination of aluminum sulfate and sodium fluoride, and the mineral admixture is one or more combinations of first-grade fly ash, microsilica fume and ultra-fine limestone powder. 2. The low-resilience shotcrete modified by emulsified asphalt according to claim 1 is characterized in that: the raw material of the low-resilience shotcrete modified by emulsified asphalt further comprises 2-6 parts by weight of high-strength shotcrete. The high-strength and high-modulus fibers are one or more combinations of polyvinyl alcohol fibers, polypropylene fibers, and PE fibers. 3 . The low-resilience shotcrete modified by emulsified asphalt according to claim 2 , wherein the polyvinyl alcohol fibers have a length of 3-5 μm. 4 . 4. The low-resilience shotcrete modified by emulsified asphalt according to claim 1 is characterized in that: said anionic emulsified asphalt is one of sulfonate emulsified asphalt, carboxylate emulsified asphalt and sulfate emulsified asphalt. one or more combinations. 5. the modified low-resilience shotcrete of emulsified asphalt according to claim 1, is characterized in that: described mineral admixture is the combination of micro-silica fume and ultra-fine limestone powder, and described micro-silica fume and ultra-fine limestone The mass ratio of the powder is 2:1, the particle size of the micro silica fume is 0.1-0.2 μm, and the particle size of the ultra-fine limestone powder is 30-35 μm. 6. the modified low-resilience shotcrete of emulsified asphalt according to claim 1, is characterized in that: described quick-setting agent is the combination of aluminum sulfate and sodium fluoride, and the mass ratio of described aluminum sulfate and sodium fluoride is 5 :1. 7. A preparation method for the modified low-resilience shotcrete of emulsified asphalt according to any one of claims 1 to 6, characterized in that: comprising the following steps: (1) Weigh each raw material component in proportion, mix river sand and limestone and sieve, the aperture of the sieve is 4.75~9.5mm, and place it in a stirring pot, then add cement and mix evenly, add water at the stirring speed. Stir for 2 minutes under the condition of 60-80 r/min, then add emulsified asphalt and quickly stir for 3 minutes under the condition of stirring speed of 120-150 r/min, and finally add mineral admixture or add mineral admixture and high strength and high modulus The amount of fiber is rapidly stirred for 1.5 min under the condition of 120-150 r/min to obtain mixture A; (2) Pour out the mixture A obtained in step (1) from the stirring pot, and pour it into the hopper of the wet spray machine, then pour the accelerator into the accelerator tube, and then start the machine, and the mixture A passes through the pressure. The slurry is pumped to the nozzle of the jet machine and fused with the accelerator, and then sprayed with compressed air.