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CN-122010502-A - Concrete composite material for roads and bridges and preparation method thereof

CN122010502ACN 122010502 ACN122010502 ACN 122010502ACN-122010502-A

Abstract

The invention belongs to the technical field of concrete, and particularly relates to a concrete composite material for roads and bridges and a preparation method thereof. The invention constructs a cementing material system by cement, fly ash and silica fume, and makes the high-strength lightweight aggregate inhale the composite internal curing liquid and then perform surface layer liquid stabilizing treatment to obtain the liquid stabilizing type liquid storage lightweight aggregate, and through the synergistic cooperation of the components in the composite internal curing liquid, the humidity retention capacity and early-age shrinkage state of the concrete are improved, a multi-scale hybrid fiber reinforcement system is further constructed by combining steel fibers and PVA fibers, and the surface activation treatment of the PVA fibers, the staged water adding wet mixing and the low-speed adding process of the later section of the liquid stabilizing type liquid storage lightweight aggregate are adopted, so that the fiber dispersion uniformity is improved, the early liquid loss risk of the lightweight aggregate in the mixing stage is reduced, and the comprehensive improvement is realized.

Inventors

  • WANG ZHONGQUAN
  • ZHANG DEJIAN
  • YANG LIANG

Assignees

  • 内蒙古万邦环境工程有限公司

Dates

Publication Date
20260512
Application Date
20260409

Claims (10)

  1. 1. The concrete composite material for roads and bridges is characterized by comprising a cementing material system, an aggregate system, a hybrid fiber system, a liquid-stabilizing type liquid storage lightweight aggregate and an additive system; the cementing material system comprises P.O 52.5.5 cement, fly ash and silica fume; The composition of the aggregate system comprises fine aggregate and coarse aggregate; the composition of the hybrid fiber system comprises steel fibers and PVA fibers; the stable liquid type liquid storage lightweight aggregate comprises the following components of high-strength lightweight aggregate, composite internal health preserving liquid and a surface stable liquid treatment system; the preparation raw materials of the composite internal health preserving liquid comprise polyether shrinkage reducing agent, distilled water, moisture retention migration regulating component and active auxiliary component; the preparation raw materials of the surface stable liquid treatment system comprise silica sol, water glass, superfine mineral powder and distilled water; The additive system comprises the following components of a polycarboxylic acid water reducer and mixing water.
  2. 2. The concrete composite material for roads and bridges according to claim 1, wherein the composition of the cementing material system comprises, by weight, 280-320 parts P.O 52.5.5 cement, 50-80 parts fly ash and 15-25 parts silica fume.
  3. 3. The concrete composite material for roads and bridges according to claim 1 is characterized in that the aggregate system comprises 680-750 parts of fine aggregate and 1000-1100 parts of coarse aggregate by weight, wherein the fine aggregate is middle sand with a fineness modulus of 2.3-3.0, and the coarse aggregate is continuous graded broken stone with a particle size of 5-15 mm.
  4. 4. The concrete composite material for roads and bridges according to claim 1 is characterized in that the composition of the hybrid fiber system comprises, by weight, 10-18 parts of steel fibers and 1.2-2.5 parts of PVA fibers, wherein the steel fibers are any one of copper-plated steel fibers, corrugated steel fibers or end hook steel fibers, and the PVA fibers are polyvinyl alcohol fibers with the length of 6-12 mm and the diameter of 20-50 mu m.
  5. 5. The concrete composite material for roads and bridges according to claim 1 is characterized in that the composition of the liquid-stabilizing type liquid-storage lightweight aggregate comprises, by weight, 90-150 parts of high-strength lightweight aggregate, 30-60 parts of composite internal health-preserving liquid and 10-30 parts of surface layer liquid-stabilizing treatment system, wherein the high-strength lightweight aggregate is high-strength shale ceramsite with the particle size of 5-10 mm.
  6. 6. The concrete composite material for roads and bridges according to claim 1 is characterized in that the preparation raw materials of the composite internal health preserving liquid comprise, by weight, 9-15 parts of polyether shrinkage reducing agent, 80-90 parts of distilled water, 1-2.5 parts of moisture retention and migration regulating component and 1-3 parts of active auxiliary component, wherein the moisture retention and migration regulating component is any one of glycerol, polyethylene glycol or hydroxyethyl cellulose, the active auxiliary component is any one of silica sol, nano silica or sodium metasilicate, and the preparation raw materials of the surface layer stabilizing treatment system comprise, by weight, 6-9 parts of silica sol, 3-6 parts of water glass, 8-12 parts of superfine mineral powder and 80-90 parts of distilled water, and the mineral powder is any one of silica fume, superfine fly ash or superfine mineral powder.
  7. 7. The concrete composite material for roads and bridges according to claim 1, wherein the composition of the additive system comprises, by weight, 5-8 parts of a polycarboxylic acid water reducer and 100-140 parts of mixing water.
  8. 8. A method for preparing a concrete composite material for roads and bridges according to any one of claims 1 to 7, characterized by comprising the following steps: S1, preparing a composite internal health preserving liquid, namely sequentially adding a polyether shrinkage reducing agent, a moisturizing migration adjusting component and an active auxiliary component into water, mixing and stirring; S2, preparing liquid-absorbing lightweight aggregate, namely drying the high-strength lightweight aggregate, vacuumizing, introducing the composite internal health preserving liquid prepared in the step S1 for dipping, and leaching surface free liquid; S3, preparing stable liquid storage lightweight aggregate, namely mixing silica sol, water glass, superfine mineral powder and water to prepare surface stable liquid treatment liquid, immersing the liquid absorption lightweight aggregate obtained in the step S2 into the treatment liquid, and then drying at low temperature; s4, fiber pretreatment, namely performing low-temperature plasma surface activation treatment on PVA fibers; s5, dry-mixing and pre-dispersing, namely mixing and dry-mixing a cementing material system and an aggregate system; s6, preparing initial slurry, namely adding part of mixing water and part of water reducer into the product of the step S5, and stirring to form initial slurry; s7, fiber dispersion, namely sequentially adding steel fibers and PVA fibers treated in the step S4 into the product of the step S6, and stirring and dispersing; s8, optimizing the flow state, namely adding the rest mixing water and the rest water reducer, and continuously stirring; and S9, mixing the lightweight aggregate, namely adding the stable liquid type liquid storage lightweight aggregate prepared in the step S3 into the product obtained in the step S8, and stirring and mixing at a low speed to obtain the concrete composite material.
  9. 9. The preparation method of the concrete composite material for roads and bridges according to claim 8 is characterized in that in the step S2, the drying temperature of the high-strength lightweight aggregate is 80-105 ℃, the vacuum degree of vacuumizing is minus 0.06-0.095 MPa, the holding time is 10-30 min, the normal pressure dipping time after releasing the vacuumizing is 30-60 min, the stirring speed of the surface stabilizing treatment liquid is 400-700 rpm, the contact treatment time of the liquid absorbing lightweight aggregate and the surface stabilizing treatment liquid is 5-15 min, the low-temperature drying temperature is 40-60 ℃, and the drying time is 1-3 h.
  10. 10. A method for preparing a concrete composite material for roads and bridges according to claim 8, wherein in the step S4, the low-temperature plasma surface activation treatment is performed in a vacuum environment, the treatment power is 80-120W, the treatment time is 100-180S, in the step S6, the added blending water amount is 60-75% of the total blending water amount, and the added polycarboxylic acid water reducing agent amount is 60-80% of the total water reducing agent amount.

Description

Concrete composite material for roads and bridges and preparation method thereof Technical Field The invention belongs to the technical field of concrete, and particularly relates to a concrete composite material for roads and bridges and a preparation method thereof. Background The concrete for road and bridge engineering is usually subjected to the common influences of vehicle load, temperature change, dry and wet circulation, freeze thawing action and external erosion medium for a long time in the service process, so that the material is required to have high compressive strength, good cracking resistance, fracture toughness, fatigue durability and long-term service stability. Especially in bridge deck pavement, road surface layers, bridge connection parts and other low-water-gel ratio high-performance concrete structures, free water in the material is relatively insufficient, obvious self-drying phenomenon easily occurs in the continuous hydration process of cement, and larger volume shrinkage and early-age cracks are induced, so that the structural integrity and the service life are influenced. In the existing road and bridge concrete, technical means of reducing the water-cement ratio, adding fly ash and silica fume, introducing a water reducer, compounding fibers and the like are generally adopted for improving the mechanical properties and durability. The low water-gel ratio and mineral admixture system is beneficial to improving the compactness and later strength of slurry, but also aggravates the internal water loss and shrinkage sensitivity in the early stage to a certain extent, and when the concrete is simply sprayed with water or covered and maintained, the water is difficult to timely supplement into the concrete, and especially for bridge deck pavement, large-area road surface layers or construction environments with limited maintenance conditions, the internal water loss problem is more prominent, so that the problems of shrinkage cracks, interface damage, local durability reduction and the like are easy to generate. In order to overcome the defects, the prior art proposes a scheme of carrying out internal curing by pre-wetting the lightweight aggregate, wherein the lightweight aggregate is used for storing water and gradually releasing the water in the hardening process so as to relieve internal self-drying, and the method adopts steel fibers, polymer fibers or a plurality of fiber compounding modes to improve the cracking resistance and the toughening performance, and further adopts the research and the application of improving the workability and the fiber dispersion state by optimizing an additive system and a stirring process. However, the following technical limitations still exist in the prior art. Firstly, the common prewetting lightweight aggregate is easy to lose liquid in advance in the mixing process, so that the effective liquid which can be released after the actual curing stage is caused to be insufficient, the internal curing effect is unstable, secondly, the single water storage type internal curing mode mainly focuses on water supplementing, the shrinkage regulation and the local humidity in a low water-cement ratio system are kept to be improved and limited, thirdly, the crack resistance or the toughness can be improved to a certain extent by singly adopting one fiber, the whole process from micro crack initiation to macro crack expansion in road and bridge concrete is still insufficient, and fourthly, the aggregation, uneven distribution and partial wrapping of the fiber, especially the small-diameter polymer fiber, in the concrete are easy to occur, so that the fluctuation of the reinforcing effect is large. Disclosure of Invention Aiming at the defects of the prior art, the invention aims to provide a concrete composite material for roads and bridges and a preparation method thereof. In order to solve the problems that the existing low water cement for roads and bridges has high risk of early-age shrinkage cracking due to rapid internal water loss of concrete, the internal curing system of lightweight aggregate has insufficient liquid retention stability, poor fiber dispersion uniformity and difficult cooperative improvement of crack resistance and toughening performance in a mixing stage, the invention constructs a cementing material system by cement, fly ash and silica fume, and leads the high-strength lightweight aggregate to be sucked into composite internal curing liquid and then to be subjected to surface layer liquid stabilization treatment, thus obtaining liquid stabilization type liquid storage lightweight aggregate, improving the internal humidity retention capacity of the concrete and the early-age shrinkage state by cooperative matching of all components in the composite internal curing liquid, further combining steel fibers and PVA fibers to construct a multi-scale hybrid fiber reinforcing system, adopting a PVA fiber surface activation treatment, staged w