CN-122010481-A - Solid waste lightweight aggregate low-shrinkage ultra-high-performance concrete and preparation method thereof

CN122010481ACN 122010481 ACN122010481 ACN 122010481ACN-122010481-A

Abstract

The invention relates to the technical field of concrete, and in particular discloses a solid waste lightweight aggregate low-shrinkage ultra-high performance concrete and a preparation method thereof, wherein the solid waste lightweight aggregate low-shrinkage ultra-high performance concrete comprises, by weight, 300-400 parts of solid waste mixed lightweight aggregate, 900-1000 parts of lightweight cement-based cementing material, 65-75 parts of composite micro-expanding agent, 200-350 parts of high-flow-state fine aggregate, 25-35 parts of water reducer, 0.1-3 parts of retarder, 15-156 parts of anti-cracking fiber, 200-250 parts of water, 3-6 parts of shrinkage reducer and 1-5 parts of defoamer. By adopting the invention, the solid waste lightweight aggregate low-shrinkage ultra-high performance concrete has high compressive strength, low shrinkage strain, low volume weight and good working performance and cracking resistance.

Inventors

QIU WENJUN
QIU KEYI
REN YANFEI
Shu Benan
YANG TENGYU
LIN JUNHAO
LI MINGYANG
Zhu Maocong
Zeng Qianpu
LI YONGLING

Assignees

佛山市交通科技有限公司

Dates

Publication Date: 20260512
Application Date: 20251231

Claims (10)

1. The low-shrinkage ultra-high performance concrete with the solid waste lightweight aggregate is characterized by comprising, by weight, 300-400 parts of solid waste mixed lightweight aggregate, 900-1000 parts of lightweight cement-based cementing material, 65-75 parts of composite micro-expanding agent, 200-350 parts of high-fluidization fine aggregate, 25-35 parts of water reducer, 0.1-3 parts of retarder, 15-156 parts of anti-cracking fiber, 200-250 parts of water, 3-6 parts of shrinkage reducer and 1-5 parts of defoamer; wherein the light cement-based cementing material consists of 45-55 parts of cement, 2-8 parts of silica fume, 15-25 parts of fly ash microbeads, 10-25 parts of fly ash and 2-5 parts of slag powder; the composite micro-expanding agent consists of magnesium oxide, calcium oxide and gypsum powder, wherein the weight ratio of the magnesium oxide to the calcium oxide to the gypsum powder is 4 (2-3) to 2-3.
2. The solid waste lightweight aggregate low shrinkage ultra-high performance concrete according to claim 1, wherein the silica fume has a SiO 2 content of greater than 92%, a 28d activity index of 120-130% and a water demand ratio of 110-120%; The fly ash microbeads are low-density hollow floating beads, the density is 1200-1500kg/m 3 , the 28d activity index is 100-110%, and the water demand ratio is 90-100%; The 28d activity index of the fly ash is 90-100%, and the water demand ratio is 95-105%; The 28d activity index of the slag powder is 98-108%, and the water demand ratio is 105-115%; The content of magnesium oxide of the magnesium oxide is 88-92%, the water content is less than or equal to 1%, and the active reaction time is 200-300 s; The calcium oxide content of the calcium oxide is 92-97%; the calcium sulfate dihydrate content of the gypsum powder is more than or equal to 95%, and the water content is less than 5%.
3. The solid waste lightweight aggregate low-shrinkage ultra-high performance concrete according to claim 1, wherein the solid waste mixed lightweight aggregate consists of clay ceramsite and coal gangue ceramsite, and the mass ratio of the clay ceramsite to the coal gangue ceramsite is (3-4) (6-7); The grain diameter of the clay ceramsite is 1.18-2.36 mm and is more than 95%, the grain diameter of the clay ceramsite is less than 1.18mm and is less than or equal to 5%, the barrel pressure strength is more than or equal to 5MPa, the compact stacking density is 600-650kg/m 3 , and the saturated water absorption is 5-7%; The particle size of 1.18-0.075 mm of the coal gangue ceramic sand accounts for more than 95%, the particle size of less than 0.075mm accounts for less than or equal to 5%, the cylinder pressure strength is more than or equal to 20MPa, the compact stacking density is 900-950kg/m 3 , and the saturated water absorption is 8-10%.
4. The solid waste lightweight aggregate low shrinkage ultra-high performance concrete according to claim 1, wherein the high flow state fine aggregate is composed of 180-220 parts of alumina microbeads, 350-380 parts of 16-26 mesh silica sand, 180-220 parts of 40-70 mesh silica sand and 210-250 parts of 70-120 mesh silica sand, and has a close packing density of 1500-1800kg/m 3 .
5. The solid waste lightweight aggregate low shrinkage ultra-high performance concrete according to claim 1, wherein the anti-crack fiber is copper-plated microfilament steel fiber or polyvinyl alcohol fiber; the copper-plated microfilament steel fibers are straight-filament fibers, the diameter is 0.20-0.23 mm, the length is 13-16 mm, the tensile strength is 2500-2800 MPa, the density is 7500-8000 kg/m 3 , and the mixing amount of concrete per cubic meter is 117-156 kg; The diameter of the polyvinyl alcohol fiber is 30-100 mu m, the length is 9-12 mm, the density is 1200-1500 kg/m 3 , and the mixing amount of concrete per cubic meter is 15-30 kg.
6. The solid waste lightweight aggregate low shrinkage ultra-high performance concrete according to claim 1, wherein the water reducer is a polycarboxylic acid type high performance water reducer; The shrinkage reducing agent is a polyether liquid shrinkage reducing agent; The defoaming agent is a polyether and mineral oil composite powder defoaming agent; The retarder is sodium citrate retarder.
7. A method for preparing the solid waste lightweight aggregate low shrinkage ultra-high performance concrete according to any one of claims 1-6, comprising the following specific steps: (1) Weighing water, a shrinkage reducing agent and a defoaming agent according to the weight parts, heating the water, adding the shrinkage reducing agent and the defoaming agent, and uniformly stirring at a high speed to obtain a prewetted impregnating solution; (2) Weighing dry solid waste mixed lightweight aggregate according to the weight proportion, adding the solid waste mixed lightweight aggregate into the pre-wetting impregnating solution, and carrying out slow stirring and soaking to enable the solid waste mixed lightweight aggregate to fully absorb water for pre-wetting to obtain a mixed product A; (3) Weighing a light cement-based cementing material, a composite micro-expanding agent and high-flow-state fine aggregate according to the weight proportion, adding the light cement-based cementing material, the composite micro-expanding agent and the high-flow-state fine aggregate into the mixed product A, and uniformly stirring in a stirrer to obtain a mixed product B; (4) Weighing a water reducing agent and a retarder according to the weight portion ratio, adding the water reducing agent and the retarder into the mixed product B, and uniformly stirring until the mixed product B is in a fluid state to obtain a mixed product C; (5) Weighing anti-cracking fibers according to the weight portion ratio, adding the anti-cracking fibers into the mixed product C, and uniformly stirring to obtain a mixed product D; (6) And (3) pouring, vibrating, finishing and maintaining the mixed product D to obtain the low-shrinkage ultra-high performance concrete with the solid waste lightweight aggregate.
8. The method for preparing the solid waste lightweight aggregate low-shrinkage ultra-high performance concrete according to claim 7, wherein in the step (1), the heating temperature of water is 40-50 ℃, the high-speed stirring speed is 400-600 r/min, and the high-speed stirring time is 2-5 min. In the step (2), the speed of slow stirring is 20-60 r/min, the time of slow stirring is 1-5 min, and the time of soaking is 4-8 h.
9. The method for preparing the solid waste lightweight aggregate low-shrinkage ultra-high performance concrete according to claim 7, wherein in the step (3), the lightweight cement-based cementing material, the composite micro-expanding agent and the high-flow-state fine aggregate are weighed according to the weight portion ratio, added into the mixed product A, and stirred uniformly in a stirrer for t1 to obtain the mixed product B; in the step (4), the water reducer and the retarder are weighed according to the weight portion ratio, added into the mixed product B, and stirred uniformly for t2 until the flow state appears, so as to obtain the mixed product C; In the step (5), the anti-cracking fiber is weighed according to the weight portion ratio, and is added into the mixed product C, and the mixed product D is obtained after uniform stirring for t 3; t1+t2+t3≤10min。
10. The method for preparing the solid waste lightweight aggregate low shrinkage ultra-high performance concrete according to claim 7, wherein in the step (6), the pouring interval is controlled to be less than or equal to 1m, the curing mode is steam curing, and the curing condition is that the curing is carried out for 60-80h at a constant temperature of 65-75 ℃ or 40-50h at a constant temperature of 85-95 ℃.

Description

Solid waste lightweight aggregate low-shrinkage ultra-high-performance concrete and preparation method thereof Technical Field The invention relates to a lightweight ultra-high performance concrete building material and a preparation method thereof, in particular to solid waste lightweight aggregate ultra-high performance concrete and a preparation method thereof. Background Ultra-high performance concrete (UHPC) has become a core material for bridge, high-rise building and repair engineering by virtue of the compressive strength of not less than 150 MPa, extremely low permeability and century durability. However, the traditional formula is highly dependent on high-energy silicate cement (the proportion is more than 65 percent), natural quartz sand and steel fibers, so that the weight of the traditional formula is high, the shrinkage cracking risk is high, the resource consumption is high, and the large-scale application of the traditional formula is severely restricted. Disclosure of Invention The invention aims to solve the problems of providing the solid waste lightweight aggregate low-shrinkage ultra-high performance concrete and the preparation method thereof, which can reduce the dead weight and have excellent mechanical properties, and an internal curing technical environment is formed in UHPC, so that water is continuously released, the self-shrinkage caused by hydration and dehydration of cement is compensated, the volume stability is improved, and the cracking risk is reduced. In order to solve the technical problems, the invention is realized by the following technical scheme: The solid waste lightweight aggregate low-shrinkage ultra-high performance concrete comprises, by weight, 300-400 parts of solid waste mixed lightweight aggregate, 900-1000 parts of lightweight cement-based cementing material, 65-75 parts of composite micro-expanding agent, 200-350 parts of high-flow-state fine aggregate, 25-35 parts of water reducer, 0.1-3 parts of retarder, 15-156 parts of anti-cracking fiber, 200-250 parts of water, 3-6 parts of shrinkage reducer and 1-5 parts of defoamer; wherein the light cement-based cementing material consists of 45-55 parts of cement, 2-8 parts of silica fume, 15-25 parts of fly ash microbeads, 10-25 parts of fly ash and 2-5 parts of slag powder; the composite micro-expanding agent consists of magnesium oxide, calcium oxide and gypsum powder, wherein the weight ratio of the magnesium oxide to the calcium oxide to the gypsum powder is 4 (2-3) to 2-3. Preferably, the SiO 2 content of the silica fume is more than 92%, the 28d activity index is 120-130%, and the water demand ratio is 110-120%; The fly ash microbeads are low-density hollow floating beads, the density is 1200-1500kg/m 3, the 28d activity index is 100-110%, and the water demand ratio is 90-100%; The 28d activity index of the fly ash is 90-100%, and the water demand ratio is 95-105%; The 28d activity index of the slag powder is 98-108%, and the water demand ratio is 105-115%; The content of magnesium oxide of the magnesium oxide is 88-92%, the water content is less than or equal to 1%, and the active reaction time is 200-300 s; The calcium oxide content of the calcium oxide is 92-97%; The calcium sulfate dihydrate content of the gypsum powder is more than or equal to 95%, the water content is less than 5%, and the fineness (45 mu m screen residue) is less than or equal to 15%; preferably, the solid waste mixed lightweight aggregate consists of clay ceramsite and coal gangue ceramic sand, wherein the mass ratio of the clay ceramsite to the coal gangue ceramic sand is (3-4) (6-7); The grain diameter of the clay ceramsite is 1.18-2.36 mm and is more than 95%, the grain diameter of the clay ceramsite is less than 1.18mm and is less than or equal to 5%, the barrel pressure strength is more than or equal to 5MPa, the compact stacking density is 600-650kg/m 3, and the saturated water absorption is 5-7%; The particle size of 1.18-0.075 mm of the coal gangue ceramic sand accounts for more than 95%, the particle size of less than 0.075mm accounts for less than or equal to 5%, the cylinder pressure strength is more than or equal to 20MPa, the compact stacking density is 900-950kg/m 3, and the saturated water absorption is 8-10%. Preferably, the high-flow state fine aggregate is composed of 180-220 parts of alumina microbeads, 350-380 parts of 16-26 mesh quartz sand, 180-220 parts of 40-70 mesh quartz sand and 210-250 parts of 70-120 mesh quartz sand, and the compact stacking density is 1500-1800kg/m 3. Preferably, the anti-cracking fiber is copper-plated microfilament steel fiber or polyvinyl alcohol fiber; the copper-plated microfilament steel fibers are straight-filament fibers, the diameter is 0.20-0.23 mm, the length is 13-16 mm, the tensile strength is 2500-2800 MPa, the density is 7500-8000 kg/m 3, and the mixing amount of concrete per cubic meter is 117-156 kg; The diameter of the polyvinyl alcohol fiber is 30-100 mu m, the len