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CN-116675464-B - Basalt fiber magnesium anticracking agent and preparation method thereof

CN116675464BCN 116675464 BCN116675464 BCN 116675464BCN-116675464-B

Abstract

The invention discloses a basalt fiber magnesium anticracking agent and a preparation method thereof, belonging to the technical field of building material additives. The basalt fiber magnesium anticracking agent comprises, by weight, 5-15 parts of a basalt fiber composite material, 80-94 parts of a magnesium expanding agent and 1-5 parts of alpha-sepiolite, wherein the basalt fiber content in the basalt fiber composite material is 70-90%, and the basalt fiber magnesium anticracking agent is used in concrete in an amount of 4-6 kg/m 3 . The basalt fiber magnesium anticracking agent of the invention aims at remarkably enhancing the tensile strength, compressive strength, impermeability, frost resistance and shock resistance of concrete by adding a proper amount of anticracking agent with micro-expansion characteristic into the concrete, thereby achieving the purpose of simultaneously improving the anticracking performance and durability of the concrete.

Inventors

  • XIAO JUXIANG
  • XIAO GUOPING

Assignees

  • 贵州蜀鑫玄武岩纤维建材有限公司
  • 达州磊金镁纤新材料科技有限公司

Dates

Publication Date
20260505
Application Date
20230607

Claims (8)

  1. 1. The basalt fiber magnesium anticracking agent is characterized by comprising, by weight, 5-15 parts of basalt fiber composite material, 80-94 parts of magnesium expanding agent and 1-5 parts of alpha-sepiolite; the content of basalt fiber in the basalt fiber composite material is 70-90%; the magnesium expanding agent is light burned magnesium oxide; the dosage of the basalt fiber magnesium anticracking agent in concrete is 4-6 kg/m 3 ; The basalt fiber composite material is prepared by the following method: activating basalt fibers and carbon nanotubes, and carrying out composite modification on the activated basalt fibers and the carbon nanotubes according to a mass ratio of 70-90:10-30 to obtain a basalt fiber composite material; the composite modification comprises the following steps: co-dissolving the activated basalt fiber and the activated carbon nano tube in an acetone solution for ultrasonic dispersion; Adding a small amount of asphalt into the dispersed solution, kneading at 160-200 ℃, and stamping, forming and roasting after kneading; the activation comprises the following steps: after sintering basalt fiber, soaking in mixed acid solution, and etching the surface to obtain activated basalt fiber; immersing the carbon nano tube in a mixed acid solution for ultrasonic dispersion to carboxylate the carbon nano tube, then washing the carbon nano tube with absolute ethyl alcohol, and drying to obtain the activated carbon nano tube.
  2. 2. The basalt fiber magnesium anticracking agent according to claim 1, wherein the basalt fiber magnesium anticracking agent comprises, by weight, 8-12 parts of basalt fiber composite material, 85-90 parts of magnesium expanding agent and 2-3 parts of alpha-sepiolite.
  3. 3. The basalt fiber magnesium anticracking agent according to claim 1 or 2, wherein the basalt fiber magnesium anticracking agent comprises the following raw materials, by weight, 10 parts of basalt fiber composite material, 87 parts of magnesium expanding agent and 3 parts of alpha-sepiolite.
  4. 4. The basalt fiber magnesia crack-resistant agent according to claim 1, wherein the content of magnesia in the light burned magnesia is more than 85%, the loss on ignition is less than 4%, the water content is less than 1%, the f-CaO content is less than 2%, and the active reaction time is 50 s-300 s.
  5. 5. The basalt fiber magnesia crack-resist of claim 1, wherein the mixed acid solution comprises 98% concentrated sulfuric acid solution and 67% concentrated nitric acid solution in a volume ratio of 3:1.
  6. 6. The basalt fiber magnesium crack inhibitor according to claim 1, wherein the basalt fiber is chopped fiber, and the fiber specification is 15-22 μm in diameter and 15-30 mm in length.
  7. 7. A method for preparing the basalt fiber magnesium crack resistance agent according to any one of claims 1 to 6, comprising the following steps: Weighing raw materials according to parts by weight, mixing the raw materials, adding absolute ethyl alcohol with the mass of 50-75% of the raw materials, and mixing by adopting a three-stage stirring method to prepare the basalt fiber magnesium anticracking agent; the three-section stirring method comprises the steps of stirring at the first section at normal temperature, heating and stirring at the second section and cooling and stirring at the third section.
  8. 8. The method for preparing the basalt fiber magnesium anticracking agent according to claim 7, wherein the stirring speed at the first section at normal temperature is 300-1000 rpm, and the stirring time is 15-30 min; The temperature of the second section of heating and stirring is 150-180 ℃, the time is 1-6 h, and the rotating speed is 4500-6000 rpm; the third section of cooling and stirring mode is natural cooling, the rotation speed of cooling and stirring is 300-1000 rpm, and the stirring time is 30-60 min.

Description

Basalt fiber magnesium anticracking agent and preparation method thereof Technical Field The invention belongs to the technical field of building material concrete additives, and particularly relates to a basalt fiber magnesium anticracking agent and a preparation method thereof. Background The concrete structure may be affected by foundation constraint, the stress concentration may be generated differently, the temperature stress may be greater than the current tensile strength of the concrete in the temperature reduction process of the concrete under the influence of the temperature difference between the inside and outside and the age, and the concrete surface may shrink in a drying way when the curing is not in time, and the conditions may cause large-scale cracks of the concrete. Along with the rapid development of society, large-volume and ultra-long structure concrete buildings are more and more, high-strength and high-performance concrete is widely used, concrete cracking causes are more complex, cracking risks are more and more serious, and concrete cracking caused by temperature stress caused by concrete hydration heat in a large-volume and ultra-long structure is particularly caused. In the construction of water conservancy and hydropower engineering, concrete temperature control measures are diversified, namely a self-built concrete mixing system of the engineering is adopted, mass concrete is usually reduced in heat insulation temperature rise value through the measures of optimizing mixing proportion, selecting high-quality raw materials, reducing concrete marks and the like, raw material temperature control mixing building outlet temperature is reduced by combining aggregate precooling, ice water mixing and the like, sunshade protection is carried out in the transportation process, microclimate is formed by spraying on a bin surface in the casting process, and cooling water is introduced in the maintenance period. Such strict temperature control still makes it difficult to avoid cracking in engineering construction, so-called "no dam and no crack". In municipal administration and traffic engineering, most of concrete is commercial concrete provided by mixing stations, the supply amount is large, raw materials, equipment and facilities and the like are relatively fixed, and concrete with ideal temperature, physical mechanics and thermodynamic indexes is difficult to provide for a single engineering. On the other hand, municipal and traffic buildings mainly adopt ' slender ' -sheet type ' structures, concrete is high in label and small in section, cooling water pipes can not be buried in the concrete basically, and the concrete can be cooled basically only naturally after being poured. Therefore, improvement of concrete performance has become an important research direction in concrete temperature control, and the most ideal concrete should have characteristics such as low heat, low elastic modulus, high tensile-compression ratio, gao Zi bulk deformation (ultimate tensile value), and the like. Several ideas have been proposed by researchers in the prior art: The first method is to regulate the hydration heat release process of the concrete by adding additives according to the concrete temperature process line, and reduce the concrete temperature peak value, which is represented by a hydration heat inhibitor. The research shows that the hydration heat inhibitor can delay the temperature peak of the concrete for about 24 hours, but can not reduce the total heat of the concrete, and the addition of the hydration heat inhibitor can obviously reduce the working performance of the mixture, reduce the early strength of the concrete and increase the later shrinkage deformation of the concrete. The second is to incorporate an additive with expansion properties to compensate for surface dry shrinkage deformation by changing autogenous volumetric deformation. Most of the common expanding agents are early expanding agents, which are represented by calcium sulfoaluminate and calcium oxide. The calcium sulfoaluminate expanding agent is mixed into concrete to generate calcium sulfoaluminate hydrate, namely ettringite, to generate volume expansion to compensate the shrinkage of the surface of the concrete, and ettringite (C 3A·3CaSO4·32H2 O) is formed in the hydration process. The expansion effect of the calcium oxide expanding agent mainly comprises the hydration of calcium oxide crystals to form calcium hydroxide crystals, so that the volume is increased. The expansion agent has the advantages of high hydration speed, rapid early expansion, large plastic deformation of concrete at the early stage, and partial expansion capacity absorption, and the expansion agent has the advantages of weak shrinkage compensation capability, large doping amount, large control difficulty of total alkali content of concrete and the like at the middle and later stages, so that the application range of the expansion agent is limi