The Preparation And Properties Of Early Strength Foamed Concrete For Protection

As a filling material with light weight, foamed concrete with high early strength, which can be used to do rush repairs and protect the road safety, can greatly improve the efficiency and quality of road engineering. On basis of silicon-aluminum complex blinding material, we studied the preparation and performance of early hardened foam concrete. We derived and simulated the ratio of matrix strength and foam concrete strength as well. The main contents and results include:(1) Three kinds of mixing technology were designed to prepare the early hardened foam concrete. One of them with a convenient cleaning which prepared cement paste with spiral mixing blade and mixed foam with compulsory mixer can not only avoid aggregate attached to the shadow, but also with a rapid preparation speed. Foamed concrete prepared by this technology has homogeneous slurry and superior stability properties.(2) After experiments, we may see foaming agent A cannot work with Aliphatic superplasticizer and poly carboxylic acid water. But it has good adaptability with naphthalene superplasticizer. The number of damaged foam will reduce when the cement paste has a increasing fluidity and decreasing viscosity or the content of foam is increased. When the dosage of superplasticizer increases or the content of foam decreases, the average pore size will enlarge.(3)There are some experiments to improve the importance of foam stability and foamed concrete liquidity used to be characterized as the initial setting time of foamed concrete. We characterize the final setting time of foamed concrete as the time when foamed concrete can suffer the load of repoured concrete.(4) When the content of Aluminate cement is 50%, silicon-aluminum composite cementitious materials do not only have a fastest setting time, but also have a moderate strength. Naphthalene series water reducing agent, fly ash, mineral powder, silica fume and early strength agent can be used to improve the properties of early hardened foam concrete. The best combination to initial setting time is 10%、10%、0、0、2%, the best combination to 28 d compressive strength is 10%、20%、9%、0.6%、2%. With the same content of foam,the relationship of fluidity between foamed concrete and cement paste is linear.(5) The bubbles of foamed concrete will be compressed under loading. The density is equal to the ratio of its pressure and standard atmospheric pressure multiplied by initial density.(6) Using the theoretical derivation and finite element to simulate the ratio of cement matrix with a zero porosity and foamed concrete, we came up with a similar conclusion--the ratiowas 6.5and 6.4 respectively. But the experimental results were in the range of 7 to 13. The early hardened foam concrete can reduce the ratio with optimizing its pore structure.