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CN-121974642-A - Basalt fiber composite modified sprayed concrete and preparation method thereof

CN121974642ACN 121974642 ACN121974642 ACN 121974642ACN-121974642-A

Abstract

The invention belongs to the technical field of concrete, and particularly relates to basalt fiber composite modified shotcrete and a preparation method thereof. The basalt fiber composite modified sprayed concrete comprises, by weight, 420-470 parts of cement, 200-220 parts of water, 830-860 parts of sand, 840-880 parts of crushed stone, 40-60 parts of an admixture, 15-30 parts of modified basalt fibers, 2-6 parts of a polycarboxylate water reducer and 5-12 parts of an alkali-free accelerator. The modified basalt fiber is added into the sprayed concrete as a reinforcing phase, so that the strength and impact toughness of the concrete can be improved, and the later strength of the concrete can be ensured. The cerium trifluoride modified fly ash is added into the admixture, so that the rebound rate can be reduced, and the early strength of concrete can be improved.

Inventors

  • ZHANG ZHIGANG
  • SHAO YANG
  • WANG JIBO
  • LI SHUNHONG
  • FENG JIONG
  • WANG FEIFEI
  • LI FENGWEI
  • YAN ZIHAN
  • WANG ZHAOFENG
  • LI JING

Assignees

  • 河南省栾卢高速公路建设有限公司
  • 河南交院工程技术集团有限公司

Dates

Publication Date
20260505
Application Date
20260211

Claims (10)

  1. 1. The basalt fiber composite modified sprayed concrete is characterized by comprising, by weight, 420-470 parts of cement, 200-220 parts of water, 830-860 parts of sand, 840-880 parts of crushed stone, 40-60 parts of an admixture, 15-30 parts of modified basalt fibers, 2-6 parts of a polycarboxylate superplasticizer and 5-12 parts of an alkali-free accelerator; The modified basalt fiber is prepared by the following preparation process: (1) Dissolving calcium nitrate, ferric nitrate, magnesium nitrate, chromium nitrate, manganese nitrate and ammonium carbonate in water, adding pretreated basalt fiber, stirring, heating, filtering, washing and drying to obtain high-entropy carbonate coated basalt fiber; (2) Dissolving a silane coupling agent in water, adding the basalt fiber coated with the high-entropy carbonate, stirring for 10-30min, filtering, washing and drying to obtain the basalt fiber coated with the modified high-entropy carbonate; (3) Mixing the basalt fiber coated by the modified high-entropy carbonate, benzaldehyde, acetone and n-butanol, regulating the pH value to 4-6, heating for reaction, filtering, washing and drying to obtain the modified basalt fiber.
  2. 2. The basalt fiber composite modified sprayed concrete of claim 1, wherein the dosage ratio of calcium nitrate, ferric nitrate, magnesium nitrate, chromium nitrate, manganese nitrate, ammonium carbonate and modified basalt fiber in the step (1) is 1mmol (0.5-2) mmol (4-12) mmol (4-5) g.
  3. 3. The basalt fiber composite modified sprayed concrete of claim 1, wherein the temperature of the stirring and heating in the step (1) is 160-180 ℃ for 10-15 hours.
  4. 4. The basalt fiber composite modified shotcrete according to claim 1, wherein the pretreated basalt fiber in the step (1) is prepared by the following preparation process that the basalt fiber is soaked in acetone for 2-3h, then is soaked in hydrochloric acid for 0.5-1h, and the pretreated basalt fiber is obtained after filtration and drying.
  5. 5. The basalt fiber composite modified shotcrete according to claim 1, wherein the silane coupling agent in the step (2) is 3-aminopropyl triethoxysilane, and the mass ratio of the silane coupling agent to the basalt fiber coated with the high entropy carbonate is (0.04-0.1): 1.
  6. 6. The basalt fiber composite modified shotcrete according to claim 1, wherein the mass ratio of the basalt fiber coated with the modified high entropy carbonate to the benzaldehyde to the acetone in the step (3) is 100 (1.5-2): 3-4), the temperature of the heating reaction is 50-80 ℃ and the time is 3-7h.
  7. 7. The basalt fiber composite modified shotcrete according to claim 1, wherein the admixture is composed of, by weight, 45-55 parts of micro silica fume, 30-35 parts of fly ash, 10-15 parts of sodium sulfate, 1-3 parts of sodium gluconate and 0.5-1 part of cerium trifluoride.
  8. 8. The basalt fiber composite modified sprayed concrete of claim 7, wherein the admixture is prepared by the following preparation process: Mixing the fly ash and cerium trifluoride in a ball mill, calcining, cooling, and then mixing with micro silica fume, sodium sulfate and sodium gluconate to obtain the admixture.
  9. 9. The basalt fiber composite modified sprayed concrete of claim 8, wherein the calcination temperature is 700 to 750 ℃ for 3 to 5 hours.
  10. 10. A method for preparing basalt fiber composite modified shotcrete according to any one of claims 1 to 9, comprising the steps of: According to the weight portions, cement, sand, broken stone, admixture and modified basalt fiber are poured into a stirrer to be dry-mixed for 1-3min, then the polycarboxylate water reducer and water are added to be wet-mixed for 2-4min, and the mixture is uniformly mixed with alkali-free accelerator before construction, so that the basalt fiber composite modified shotcrete is obtained.

Description

Basalt fiber composite modified sprayed concrete and preparation method thereof Technical Field The invention belongs to the technical field of concrete, and particularly relates to basalt fiber composite modified shotcrete and a preparation method thereof. Background The sprayed concrete is a special concrete material formed by spraying the ready-mixed concrete mixture to a sprayed surface at a high speed through a spraying machine by means of compressed air power and rapidly solidifying. Compared with the traditional cast-in-situ concrete, the sprayed concrete has the advantages of high early strength, good impermeability, strong flexibility, low manufacturing cost and the like, and is widely applied to the fields of hydraulic and hydroelectric engineering, mine roadway support, tunnel lining, underground structure reinforcement and the like. However, the sprayed concrete has the defects of easy shrinkage crack, low later strength and the like, and the phenomena of cracking, peeling, even damage and the like often occur under a complex environment, so that the safety and stability of the structure are seriously endangered. In order to ensure the safe construction and long-term use of engineering, the concrete needs to be modified and reinforced. Basalt fiber is a green high-performance fiber developed in recent years, and is parallel to carbon fiber, aramid fiber and ultra-high molecular weight polyethylene, which are four high-tech fibers developed in China. The basalt fiber has excellent performances of high temperature resistance, low temperature resistance, high breaking strength, low elongation, high elastic modulus and the like, and researches show that the strength and toughness of the concrete can be obviously improved by doping a certain content of basalt fiber in sprayed concrete, the brittle failure characteristic of the concrete is improved, and the durability is improved. However, the application environment of the sprayed concrete is more and more complex, the basalt fiber has smooth surface, is chemically inert, has weak interaction with a matrix and low interface bonding strength, has limited reinforcing effect on the sprayed concrete, and needs to be compounded with a reinforcing phase in the concrete or to be compounded and modified to complement the basalt fiber in different performances so as to achieve better improving effect. Disclosure of Invention The first aim of the invention is to provide basalt fiber composite modified shotcrete, which has excellent early compressive strength, excellent later compressive strength and good rebound performance. The second aim of the invention is to provide a preparation method of the basalt fiber composite modified shotcrete. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: The basalt fiber composite modified sprayed concrete comprises, by weight, 420-470 parts of cement, 200-220 parts of water, 830-860 parts of sand, 840-880 parts of crushed stone, 40-60 parts of an admixture, 15-30 parts of modified basalt fibers, 2-6 parts of a polycarboxylate superplasticizer and 5-12 parts of an alkali-free accelerator; The modified basalt fiber is prepared by the following preparation process: (1) Dissolving calcium nitrate, ferric nitrate, magnesium nitrate, chromium nitrate, manganese nitrate and ammonium carbonate in water, adding pretreated basalt fiber, stirring, heating, filtering, washing and drying to obtain high-entropy carbonate coated basalt fiber; (2) Dissolving a silane coupling agent in water, adding the basalt fiber coated with the high-entropy carbonate, stirring for 10-30min, filtering, washing and drying to obtain the basalt fiber coated with the modified high-entropy carbonate; (3) Mixing the basalt fiber coated by the modified high-entropy carbonate, benzaldehyde, acetone and n-butanol, regulating the pH value to 4-6, heating for reaction, filtering, washing and drying to obtain the modified basalt fiber. Further, the dosage ratio of the calcium nitrate, the ferric nitrate, the magnesium nitrate, the chromium nitrate, the manganese nitrate, the ammonium carbonate and the modified basalt fiber in the step (1) is 1mmol (0.5-2) mmol (4-12) mmol (4-5) g. Further, the temperature of stirring and heating in the step (1) is 160-180 ℃ and the time is 10-15h. Further, the pretreated basalt fiber in the step (1) is prepared by the following preparation process that the basalt fiber is soaked in acetone for 2-3 hours, then is soaked in hydrochloric acid for 0.5-1 hour, and is obtained after filtration and drying. Further, the silane coupling agent in the step (2) is 3-aminopropyl triethoxysilane, and the mass ratio of the silane coupling agent to the basalt fiber coated by the high-entropy carbonate is (0.04-0.1): 1. Further, in the step (3), the mass ratio of the basalt fiber coated by the modified high-entropy carbonate to the benzaldehyde to the acetone is 100 (1.5-2) (3-4), the temperature of t