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CN-122010511-A - Silicate modified fly ash-based low-temperature grouting material and preparation method thereof

CN122010511ACN 122010511 ACN122010511 ACN 122010511ACN-122010511-A

Abstract

The invention discloses a silicate modified fly ash-based low-temperature grouting material and a preparation method thereof, and belongs to the technical field of grouting materials. The grouting material is formed by mixing dry-mixed powder and water, wherein the dry-mixed powder comprises silicate modified fly ash, a basic gelatinization component, a low-temperature nucleation component, a water phase regulation component and a rheology regulation component, and the silicate modified fly ash is core-shell structure particles with a silicate coating layer on the surface. The invention also discloses a preparation method of the fly ash pretreatment, surface composite modification, temperature control drying film forming, step-by-step dry mixing and on-site water addition pulping. The material is suitable for grouting construction under the low-temperature condition.

Inventors

  • JIA ZHAO
  • SHI XIAOLIANG
  • GUO JIWEI

Assignees

  • 山西浩博瑞新材料有限公司

Dates

Publication Date
20260512
Application Date
20260410

Claims (10)

  1. 1. A silicate modified fly ash-based low-temperature grouting material is characterized in that the grouting material is formed by mixing dry-mixed powder and water; The dry mixed powder comprises, by mass, 20-60 parts of silicate modified fly ash, 20-50 parts of basic gelling components, 2-10 parts of low-temperature nucleation components, 2-7 parts of water phase regulation components and 0.2-1.5 parts of rheology regulation components; the addition amount of the water is 40% -60% of the total mass of the dry-mixed powder; the silicate modified fly ash is a core-shell structure particle, and the core-shell structure particle comprises a fly ash core and a silicate coating layer coated on the surface of the fly ash core.
  2. 2. The silicate modified fly ash based low temperature grouting material of claim 1, wherein the silicate coating layer is formed by in situ deposition of silicate modifier on the surface of the fly ash core; The silicate modifier comprises one or at least two of water glass, sodium metasilicate, potassium metasilicate, lithium silicate and silicic acid sol.
  3. 3. The silicate-modified fly ash-based low-temperature grouting material of claim 2, wherein the basic gelling component comprises at least one of silicate cement, sulphoaluminate cement and slag micropowder.
  4. 4. The silicate-modified fly ash-based low temperature grouting material as claimed in claim 3, wherein the low temperature nucleation component comprises soluble calcium salt and nano seed crystal; wherein the soluble calcium salt is selected from at least one of calcium formate, calcium nitrate or calcium nitrite; The nano seed crystal is selected from nano C-S-H seed crystal or nano silicon dioxide, the average grain diameter of the nano seed crystal is 10 nm-100 nm, and the nano seed crystal is dispersed in dry powder in dry mixed powder of the grouting material.
  5. 5. The silicate-modified fly ash-based low-temperature grouting material of claim 4, wherein the water phase regulating component comprises inorganic antifreezing salt and polyalcohol; Wherein the inorganic antifreezing salt is selected from at least one of sodium formate or sodium nitrate, and the polyalcohol is selected from at least one of ethylene glycol, propylene glycol or glycerol.
  6. 6. The silicate-modified fly ash-based low temperature grouting material of claim 5, wherein the rheology-adjusting component comprises a water reducing agent and a thickener; The water reducer is a polycarboxylic acid water reducer with a main chain and polyether side chain comb-shaped structure, and the thickener is at least one of xanthan gum or modified cellulose ether.
  7. 7. The silicate-modified fly ash-based low temperature grouting material as claimed in claim 6, wherein the silicate coating layer is an amorphous silicate pre-gel layer with low polymerization degree; And the silicate modifier forming the silicate coating layer accounts for 0.5-8.0% of the mass of the fly ash core according to the dry matrix amount.
  8. 8. A method for preparing a silicate modified fly ash-based low-temperature grouting material, which is used for preparing the grouting material of any one of claims 1 to 7, and is characterized by comprising the following steps: S1, pre-treating the fly ash, wherein the pre-treating comprises the steps of sequentially drying, dehydrating, screening and removing impurities from raw fly ash to obtain fly ash with the water content lower than 1.0%, and then grinding and mechanically activating the fly ash to obtain the fly ash inner core with the specific surface area of 400m 2 /kg～700m 2 /kg; S2, carrying out surface composite modification on the fly ash core by adopting a liquid silicate modifier, enabling the silicate modifier to be deposited on the surface of the fly ash core in situ, and drying at a controlled temperature to form the silicate coating layer, so as to obtain the silicate modified fly ash with a core-shell structure; S3, mixing the silicate modified fly ash with a basic gelling component, a low-temperature nucleation component, a water phase regulating component and a rheology regulating component to obtain premixed grouting dry-mixed powder; S4, adding water into the ready-mixed grouting dry-mixed powder obtained in the step S3 according to the proportion of 40% -60% of the total mass of the dry-mixed powder, and uniformly stirring to obtain the low-temperature grouting material.
  9. 9. The method for preparing the silicate-modified fly ash-based low-temperature grouting material according to claim 8, wherein in the step S2, the silicate modifier acts on the surface of the fly ash by at least one of dipping, atomizing spraying or high-speed stirring cladding; The temperature of the temperature-controlled drying is controlled to be 50-120 ℃ and the time is controlled to be 1-4.5 hours.
  10. 10. The method for preparing the silicate modified fly ash-based low-temperature grouting material according to claim 9, wherein the specific mixing process in the step S3 is that the silicate modified fly ash, a basic gel component and a rheology regulating component are firstly dry-mixed and premixed, and then the low-temperature nucleation component and the water phase regulating component are added and mixed uniformly.

Description

Silicate modified fly ash-based low-temperature grouting material and preparation method thereof Technical Field The invention belongs to the technical field of grouting materials, and particularly relates to a silicate modified fly ash-based low-temperature grouting material and a preparation method thereof. Background The fly ash is used as a large amount of pozzolanic material, so that the cost of the material of the grouting material can be effectively reduced by adding the fly ash into the grouting material, the effective utilization of solid waste can be improved, the improvement of green of the building material is improved, and the rheological property of the slurry can be effectively improved when the fly ash is added into the grouting material through morphological effect and micro-aggregate effect. However, fly ash has a defect of insufficient early activity at normal temperature, and the defect is greatly amplified in a low-temperature environment. The low temperature not only inhibits the gelation reaction and the elongation induction period, but also can be accompanied by free water freezing and ion migration blocking. The fly ash is easy to be degraded from a functional component to an inert dilution component in a low-temperature system, so that early hydration of the slurry is delayed, the setting time is greatly prolonged, the calculus rate is reduced and the early bearing capacity is insufficient. Aiming at the problem of insufficient activity of a fly ash system under low temperature, the prior art adopts two compensation ideas, namely, the reaction condition is maintained through an external heat source, for example, CN102976699B clearly records the traditional methods of preheating, hot water stirring, heat preservation after grouting and the like, and the early reaction is enhanced through quick hardening cement, instant sodium silicate, antifreezing agent, strong salt or low-temperature coagulant, for example, CN102173662A adopts quick hardening cement, double quick hardening cement, instant sodium silicate, early-strength agent and antifreezing agent to construct a low-temperature super-early-strength support grouting material, and CN110218055B adopts a nucleation-shell structure through preparing the coagulant, so that quick coagulation is realized at low temperature. However, the core of the core-shell structure is a low temperature setting accelerator (e.g., aluminate, carbonate, etc.), and the shell is a slow release coating that is designed to control the rate of release of the setting accelerator rather than to alter the location where the reaction occurs. The former type of scheme has complex construction and high energy consumption, while the latter type of scheme can promote the low-temperature reaction rate, the latter type of scheme also easily brings the problems of indiscriminate acceleration in liquid phase, narrow construction window, even increased durability and corrosion risk, and the like. Therefore, the prior art still lacks a fly ash-based grouting material capable of self-starting a low-temperature curing mechanism under the heating-free and heat-preservation-free conditions and converting the fly ash from a traditional dilution filling component into a low-temperature functional reaction component. Disclosure of Invention In order to make up the defects of the prior art, the invention provides a silicate modified fly ash-based low-temperature grouting material and a preparation method thereof. The invention is mainly used for solving the problems that the activity release of the existing grouting material doped with the fly ash is blocked at low temperature, the coagulation is delayed and the external thermal process is seriously depended. According to one aspect of the invention, a silicate modified fly ash-based low-temperature grouting material is provided, and the low-temperature grouting material is formed by mixing dry-mixed powder and water; The dry-mixed powder comprises, by mass, 20-60 parts of silicate modified fly ash, 20-50 parts of basic gelling components, 2-10 parts of low-temperature nucleation components, 2-7 parts of water phase regulation components and 0.2-1.5 parts of rheology regulation components; the addition amount of water is 40% -60% of the total mass of the dry-mixed powder; The silicate modified fly ash is a core-shell structure particle, and the core-shell structure particle comprises a fly ash core and a silicate coating layer coated on the surface of the fly ash core. When the low-temperature activity of the fly ash-based low-temperature grouting material is insufficient in the prior art, a mode of directly adding a strong excitant, an antifreezing agent or a coagulant into mixing water or a liquid phase component is generally adopted, so that the active component is quickly dissolved in the liquid phase and participates in the reaction. Although the reaction rate of the solution under the low-temperature condition can be improv