| In recent years, the annual emissions of various types of construction waste up to 20 million tons in Guangzhou, and there is a total of about 60 million tons of construction wastecoupled with the construction waste of nearly ten years. This leads to 6000 acres of landfill to be occupiedeach year.Therefore, a huge amount of construction waste has become a major obstacle to the process of the city.According to the research results of the experts and scholar,in recent years, crushing the construction waste and processing them into foam concrete forsoft base embankment backfill on bridge abutment is a kind of good method to solve the problems.Construction waste recycled aggregate foam concrete is a new type of lightweight fill material composed of waste recycled set material, water, foam, cement cementitious material and admixture by mixing with a certain proportion after curing and forming. Construction waste recycled aggregate foam concrete further reduces the economic cost of foamed concrete, and is an extension product of foamed concrete. In addition, recycling of construction waste has solved the problem of construction waste dumping landfill, etc. Therefore, the construction waste recycled aggregate foam concrete has good prospects for development. Through a large number of experiment,the conclusions of the studies are as follows in this paper:?1?It is found that composite foaming agent is the best choice and the best dilution is 1:40by comparing a variety of mainstream foaming agent performance.In addition,the optimum foaming multiple is 34.1, the settlement distance of 1 hour is 6mm, and bleeding of 1 houris 16mL;?2?Adding a small amount of HPMC foam stabilizer can increase the foaming multiple of the composite foaming agent, reduce the surface energy of the bubble, and the foaming multiple effect is the best when the content is 0.1%. The amount of bleeding after 1 hours reduced to 6mL, 3 hours of bleeding amount was reduced to 15mL;?3? The primary and secondary order of the influencing factors on the 28 d unconfined compressive strength of the building waste aggregate foam concrete is sand-cement ratio, cement, water cement ratio;?4? With the increasing content of polypropylene fiber, construction waste recycled aggregate foam concrete shrinkage rate gradually decreases. But the flow rate decreased with the increase of polypropylene fiber content. It is the most reasonable when the content of the polypropylene fiber is 0.2%, and the28 dshrinkage rate is 9.971 × 10-6;?5? Adding super plasticizer can reduce shrinkage of construction waste recycled aggregate foam concrete. The dry shrinkage rate is the lowest when the amount of super plasticizer is 0.2%,and the dry shrinkage rate of 28 d is 936.1 × 10-6. With the increase of the content of the high efficiency water reducing agent, the water absorption rate of the water reducing agent is decreased continuously. Among them, the water absorption is the lowest when the agent of the high efficiency water was 0.3%, and the water absorption rate of 28 d was 22%;?6? The best mix proportion of construction waste recycled aggregate foam concrete is determined through experimental study. 1 cubic meters of cement mixed with cement 405 kg, construction waste recycled aggregate 607.5kg, water 243 kg, bubble 308.97 L, HPMC foam stabilizer 3.09 L, poly carboxylic acid high efficiency water reducing agent 1.22 kg, and polypropylene fiber 2.6kg. The unconfined compressive strength of 28 d is 4.85 MPa, the flow rate is 170 mm. And the above indexesall meet the requirements of the Technical specification for filling engineering of air bubble mixed light soil,CJJ/T177-2012. |
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