CN114105508A

CN114105508A - Method for modifying basalt fibers in basalt fiber shotcrete for tunnel

Info

Publication number: CN114105508A
Application number: CN202111621699.XA
Authority: CN
Inventors: 刘丽丽; 郭林健; 张梓业; 郑彪
Original assignee: Beijing Xuanze New Material Technology Co ltd
Current assignee: Beijing Xuanze New Material Technology Co ltd
Priority date: 2021-12-28
Filing date: 2021-12-28
Publication date: 2022-03-01
Anticipated expiration: 2041-12-28
Also published as: CN114105508B

Abstract

The invention discloses a method for modifying basalt fibers in basalt fiber shotcrete for a tunnel, which comprises the following steps: firstly, soaking basalt fibers in an acetone solution for 2 hours, completely washing the basalt fibers with tap water, soaking the basalt fibers in a silane coupling agent-absolute ethyl alcohol solution for 1 hour after drying the basalt fibers, taking the basalt fibers out, then heating the basalt fibers in a 120-DEG C drying oven for 1 hour to completely react the basalt fibers with the silane coupling agent, cooling the basalt fibers for use, and performing thermal improvement treatment on the basalt fibers before soaking the basalt fibers in the silane coupling agent-absolute ethyl alcohol solution, and then placing the basalt fibers in a surface modification solution for treatment. Active groups of the KH560 type silane coupling agent can form hydrogen bonds or covalent bonds with the surface of basalt, and each unit group is dehydrated and condensed by a Si-O main chain, so that a continuous new surface layer is formed on the surface of the fiber, the defects on the surface of the fiber are repaired, filled and wrapped, and the weak links of the fiber are reduced.

Description

Method for modifying basalt fibers in basalt fiber shotcrete for tunnel

Technical Field

The invention relates to the technical field of basalt fibers, in particular to a method for modifying basalt fibers in basalt fiber shotcrete for a tunnel.

Background

The sprayed concrete is a kind of concrete which is formed by spraying concrete with a certain mixing ratio onto the sprayed surface at a high speed by means of a spraying machine and utilizing compressed air or other power to solidify and harden. The sprayed concrete construction is simple and rapid, the procedures of formwork erecting, pouring, formwork removing and the like are omitted, the concrete is conveyed, poured and vibrated into one procedure, manpower and material resources are saved, the construction period is shortened, the flexibility of the sprayed concrete construction is high, and the sprayed concrete construction is widely applied to the environment of narrow space operation such as tunnel supporting, tunnel reinforcing and the like.

However, shotcrete has problems such as poor economical efficiency due to a high rebound ratio (i.e., unadhered (detached) concrete when sprayed on a structure), and a decrease in concrete compactness due to a decrease in the rebound ratio by a reduction in wind pressure.

After the basalt fibers are doped, the rebound rate of the sprayed concrete can be effectively reduced, the wind pressure of a spraying machine can be improved, the spraying speed and the construction quality are improved, but the flowability of the concrete is reduced due to the characteristics of the fibers, and the construction speed is reduced.

Based on the method, the invention provides a method for modifying basalt fibers in basalt fiber shotcrete for a tunnel.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a method for modifying basalt fibers in basalt fiber shotcrete for a tunnel, so as to solve the problems in the background art.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the invention provides a method for modifying basalt fibers in basalt fiber shotcrete for a tunnel, which comprises the following steps:

step one, heating basalt fibers in an oven at 250 ℃ for 2 hours, cooling, placing the basalt fibers in an acetone solution, soaking for 2 hours, taking out the basalt fibers, washing the basalt fibers with tap water for multiple times until the basalt fibers are clean, and then drying the basalt fibers in the natural environment;

and step two, after the basalt fiber is dried, soaking the basalt fiber in a silane coupling agent-absolute ethyl alcohol solution for 1 hour, taking out the basalt fiber, then placing the basalt fiber in a drying oven at the temperature of 120 ℃ for heating for 1 hour to enable the basalt fiber and the silane coupling agent to completely react, and cooling the basalt fiber and the silane coupling agent for use.

Preferably, in the second step, before the silane coupling agent-absolute ethyl alcohol solution is soaked, basalt fibers are further adopted for thermal improvement treatment, and then the basalt fibers are placed in the surface modification liquid for treatment.

Preferably, the specific operation method of the thermal improvement treatment is as follows:

s1: reacting basalt fiber at 45-55 ℃ for 15-25 min;

s2: then placing the mixture into a sodium phosphite solution for reaction for 10-20min, wherein the reaction temperature is 65-75 ℃, the reaction rotating speed is 100-;

s3: and then preserving heat at 75-95 ℃ for 5-10min, then raising the temperature to 120 ℃ at the speed of 1-3 ℃/min, continuing preserving heat for 1-5min, and naturally cooling to room temperature after finishing preserving heat.

Preferably, the mass fraction of the sodium phosphite solution is 10-20%.

Preferably, the treatment method of the surface modification liquid comprises the steps of placing the basalt fibers in the surface modification liquid for proton irradiation treatment, then adopting plasma treatment, and finishing the treatment.

Preferably, the power of the proton irradiation treatment is 100-300W, and the treatment time is 5-10 min; the processing power of the plasma processing is 50-100W, and the processing time is 10-20 min.

Preferably, the power of the proton irradiation treatment is 300W, and the treatment time is 7.5 min; the processing power of the plasma treatment was 75W, and the processing time was 15 min.

Preferably, the surface modification liquid is 10-20% of sodium citrate by mass fraction.

Preferably, the mass fraction of the sodium citrate is 15%.

Preferably, the preparation method of the silane coupling agent-absolute ethyl alcohol solution is as follows:

dissolving 0.6-0.8% of KH560, 0.2-0.4% of A172 and 0.1-0.2% of KH902 in absolute ethanol to obtain a solution of silane coupling agent and absolute ethanol.

Compared with the prior art, the invention has the following beneficial effects:

active groups of the KH560 type silane coupling agent can form hydrogen bonds or covalent bonds with the surface of basalt, and each unit group is dehydrated and condensed by a Si-O main chain, so that a continuous new surface layer is formed on the surface of the fiber, the defects on the surface of the fiber are repaired, filled and wrapped, and the weak links of the fiber are reduced; the A172 type silane coupling agent can react on the surface of the fiber to hydrophobize the surface of the fiber, so that the self-dispersing performance of the fiber is better, the dispersibility of the basalt fiber in a concrete system is fundamentally improved, and the probability of agglomeration is reduced; the KH902 type silane coupling agent treatment can enhance the antistatic capacity among fibers and also can play a role in enhancing the dispersibility of the fibers in concrete; in addition, the KH902 can soften the basalt fibers to a certain extent, and after the fibers are softened, the loss of the basalt fibers (for example, the basalt fibers are broken due to being too hard) in the concrete stirring process (generally, the mixture of sand, pebbles and fibers is stirred firstly) can be reduced, so that the KH902 also has a certain help for improving the spraying efficiency in the future concrete spraying;

meanwhile, the active energy of the fiber surface is increased through the treatment of the sodium phosphite solution, the active energy of the product is further improved through the further treatment of thermal improvement, and the active energy of the product can be obviously enhanced through the activation of the sodium citrate and the matching of proton irradiation treatment and plasma treatment, so that the subsequent bonding capability of the silane coupling agent and the fiber surface is facilitated, and the overall improvement effect of the product is improved.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below with reference to specific embodiments, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Dissolving 0.6-0.8% of KH560+ 0.2-0.4% of A172+ 0.1-0.2% of KH902 silane coupling agent in absolute ethyl alcohol, and uniformly stirring for later use.

Before the surface modification of the basalt fiber, pretreatment is carried out in advance: heating the basalt fiber in an oven at 250 ℃ for 2 hours, cooling, soaking in an acetone solution for 2 hours, taking out, washing with tap water for multiple times until the basalt fiber is clean, and then drying in the natural environment.

After being dried, the basalt fiber is soaked in the silane coupling agent-absolute ethyl alcohol solution prepared in the first step for 1 hour and then taken out, and then the soaked basalt fiber and the silane coupling agent are heated in a drying oven at the temperature of 120 ℃ for 1 hour to enable the basalt fiber and the silane coupling agent to be completely reacted, and the basalt fiber and the silane coupling agent can be used after being cooled.

Property change of modified basalt fiber

(Change in Property represented by KH 560-0.7%; A172-0.3%; KH 902-0.1%):

	tensile Strength (MPa)	Elongation at Break (%)
			Fibrils	2332	2.51
Modified fiber	2454	2.72

The tensile strength of the treated basalt fiber is improved by 5.2%, the elongation at break is increased by 8.4%, and the appearance is not obviously changed.

Aspect of concrete Properties

Fluidity of the product itself

The slump and the expansion are reduced less, and the V leakage time is greatly reduced compared with that of unmodified fibers and is close to that of concrete not doped with basalt fibers;

strength of concrete

The compressive strength of the concrete is not obviously influenced (all belong to normal test errors), the flexural strength of the concrete can be effectively improved, and the surface modified basalt fiber has no obvious difference from the unmodified basalt fiber;

the construction performance of the sprayed concrete doped with basalt fibers.

Example 1:

the method for modifying the basalt fibers in the basalt fiber shotcrete for the tunnel comprises the following steps:

In the second step of this embodiment, before the silane coupling agent-absolute ethanol solution is soaked, basalt fibers are further used for thermal modification treatment, and then the basalt fibers are placed in the surface modification solution for treatment.

The specific operation method of the thermal improvement treatment of the embodiment is as follows:

s1: reacting basalt fibers at 45 ℃ for 15 min;

s2: then placing the mixture into a sodium phosphite solution for reaction for 10min, wherein the reaction temperature is 65 ℃, the reaction speed is 100r/min, and the reaction is finished;

s3: and then preserving heat at 75 ℃ for 5min, then heating to 120 ℃ at the speed of 1 ℃/min, continuing preserving heat for 1min, finishing heat preservation, and naturally cooling to room temperature.

The mass fraction of the sodium phosphite solution in this example was 10%.

The treatment method of the surface modification liquid of the embodiment is to place the basalt fiber in the surface modification liquid to perform proton irradiation treatment, then adopt plasma treatment, and finish the treatment.

The power of the proton irradiation treatment in this embodiment is 100W, and the treatment time is 5 min; the processing power of the plasma processing was 50W, and the processing time was 10 min.

The surface modification liquid in this example was sodium citrate with a mass fraction of 10%.

The preparation method of the silane coupling agent-absolute ethyl alcohol solution of the embodiment is as follows:

silane coupling agents in the amount fractions of 0.6% KH560, 0.2% A172 and 0.1% KH902 were dissolved in absolute ethanol to obtain a silane coupling agent-absolute ethanol solution.

Example 2:

s1: reacting basalt fibers at 55 ℃ for 25 min;

s2: then placing the mixture into a sodium phosphite solution for reaction for 20min, wherein the reaction temperature is 75 ℃, the reaction speed is 200r/min, and the reaction is finished;

s3: and then keeping the temperature at 95 ℃ for 10min, then heating to 120 ℃ at the speed of 3 ℃/min, continuing keeping the temperature for 5min, and naturally cooling to room temperature after the temperature is kept.

The mass fraction of the sodium phosphite solution of this example was 20%.

The power of the proton irradiation treatment in this example is 300W, and the treatment time is 10 min; the processing power of the plasma processing was 100W, and the processing time was 20 min.

The surface modification liquid in this example was sodium citrate with a mass fraction of 20%.

silane coupling agents in the amount fractions of 0.8% KH560, 0.4% A172 and 0.2% KH902 were dissolved in absolute ethanol to obtain a silane coupling agent-absolute ethanol solution.

Example 3:

s1: reacting basalt fibers at 50 ℃ for 20 min;

s2: then placing the mixture into a sodium phosphite solution for reaction for 15min, wherein the reaction temperature is 70 ℃, the reaction speed is 150r/min, and the reaction is finished;

s3: and then keeping the temperature at 80 ℃ for 7.5min, then heating to 120 ℃ at the speed of 2 ℃/min, continuing keeping the temperature for 3min, and naturally cooling to room temperature after the heat preservation is finished.

The mass fraction of the sodium phosphite solution of this example was 15%.

The power of the proton irradiation treatment in this example is 300W, and the treatment time is 7.5 min; the processing power of the plasma treatment was 75W, and the processing time was 15 min.

The surface modification liquid in this example was sodium citrate with a mass fraction of 15%.

silane coupling agents in the amount fractions of 0.7% KH560, 0.3% A172 and 0.15% KH902 were dissolved in absolute ethanol to obtain a silane coupling agent-absolute ethanol solution.

Example 4:

s1: reacting basalt fibers at 47 ℃ for 20 min;

s2: then placing the mixture into a sodium phosphite solution for reaction for 12min, wherein the reaction temperature is 67 ℃, the reaction speed is 120r/min, and the reaction is finished;

s3: and then keeping the temperature at 80 ℃ for 6min, then heating to 120 ℃ at the speed of 1.5 ℃/min, continuing keeping the temperature for 2min, and naturally cooling to room temperature after the heat preservation is finished.

The mass fraction of the sodium phosphite solution in this example was 12%.

The power of the proton irradiation treatment in this embodiment is 120W, and the treatment time is 6 min; the processing power of the plasma processing was 60W, and the processing time was 12 min.

The surface modification liquid in this example was sodium citrate with a mass fraction of 12%.

silane coupling agents in the amount fractions of 0.65% KH560, 0.25% A172 and 0.12KH902 were dissolved in absolute ethanol to obtain a silane coupling agent-absolute ethanol solution.

Example 5:

s1: reacting basalt fibers at 52 ℃ for 22 min;

s2: then placing the mixture into a sodium phosphite solution for reaction for 18min, wherein the reaction temperature is 72 ℃, the reaction rotating speed is 180r/min, and the reaction is finished;

s3: and then keeping the temperature at 90 ℃ for 8min, then heating to 120 ℃ at the speed of 2 ℃/min, continuing keeping the temperature for 4min, and naturally cooling to room temperature after the temperature is kept.

The mass fraction of the sodium phosphite solution of this example was 18%.

The power of the proton irradiation treatment in this embodiment is 260W, and the treatment time is 8 min; the processing power of the plasma treatment was 80W, and the processing time was 18 min.

The surface modification liquid in this example was sodium citrate with a mass fraction of 18%.

silane coupling agents in the amount fractions of 0.7% KH560, 0.35% A172 and 0.18% KH902 were dissolved in absolute ethanol to obtain a silane coupling agent-absolute ethanol solution.

The product is subjected to thermal improvement treatment, and then the product is placed in surface modification liquid for treating the workability of the sprayed concrete of the basalt fiber.

As can be seen from examples 1-5, the basalt fiber treated by thermal modification and then placed in the surface modification liquid of the invention has further improved product performance in concrete.

MPa	7d resistance to compression	28d resistance to compression	7d bending resistance	28d bending resistance
					Example 1	26.3	33.2	5.8	8.9
Example 2	26.4	33.4	5.9	9.1
					Example 3	26.5	33.8	5.9	9.3
Example 4	26.2	33.1	5.8	9.0
					Example 5	26.1	33.3	5.8	9.1

Strength of concrete

The modified product has improved compressive strength to concrete and can effectively improve the strength performance of concrete.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. The method for modifying the basalt fiber in the basalt fiber shotcrete for the tunnel is characterized by comprising the following steps of:

2. The method for modifying basalt fibers in basalt fiber shotcrete for tunnels according to claim 1, wherein in the second step, before the soaking in the silane coupling agent-absolute ethyl alcohol solution, the basalt fibers are further subjected to thermal modification treatment, and then are placed in the surface modification solution for treatment.

3. The method for modifying basalt fibers in basalt fiber shotcrete for tunnels according to claim 2, wherein the specific operation method of the thermal modification treatment is:

s1: reacting basalt fiber at 45-55 ℃ for 15-25 min;

4. The method for modifying basalt fibers in basalt fiber shotcrete for tunnels according to claim 3, wherein the mass fraction of the sodium phosphite solution is 10 to 20%.

5. The method for modifying basalt fibers in basalt fiber shotcrete for tunnels according to claim 2, wherein the surface modification solution is prepared by placing basalt fibers in the surface modification solution to perform proton irradiation treatment, then performing plasma treatment, and finishing the treatment.

6. The method for modifying the basalt fiber in the basalt fiber shotcrete for the tunnel according to claim 5, wherein the power of the proton irradiation treatment is 100-300W, and the treatment time is 5-10 min; the processing power of the plasma processing is 50-100W, and the processing time is 10-20 min.

7. The method for modifying basalt fibers in basalt fiber shotcrete for tunnels according to claim 6, wherein the power of the proton irradiation treatment is 300W, and the treatment time is 7.5 min; the processing power of the plasma treatment was 75W, and the processing time was 15 min.

8. The method for modifying basalt fibers in basalt fiber shotcrete for tunnels according to claim 5, wherein the surface modification liquid is sodium citrate with a mass fraction of 10 to 20%.

9. The method for modifying basalt fibers in basalt fiber shotcrete for tunnels according to claim 8, wherein the mass fraction of the sodium citrate is 15%.

10. The method for modifying basalt fibers in basalt fiber shotcrete for tunnels according to claim 1, wherein the method for preparing the silane coupling agent-absolute ethyl alcohol solution comprises: