Optimization Design And Performance Study Of High Stable Foaming Agent And Foamed Concrete

With the growing road traffic volume and traffic loads in China, the expansion of some earlyhighways and urban roads is taking up more and more in our road construction nowadays. Thehouse demolition, the treatment of soft soil foundation, destruction of frozen soil area, and thepipe culvert construction of outside heat preservation problem in road base construction anddestruction has not been effectively resolved. As a kind of self-reliance, frostresistance, good insulation wide source and low price of new road base materials, foamconcrete, has been widely used and developed in road base construction, but it also appearedproblems, such as foam instability, low strength and excessive water absorption. According to the"Technical Specifications for Construction Pavement Base"(JTJ034-2000) in the strength of thebase material requirements, preparation and optimization design of high stable foaming agent andfoamed concrete in this article, and systematically explore the factors affecting foam concrete,foam and its internal pore structure and improvement measures. The main contents include:(1) By comparing the performance of different anionic surfactant foam, and the foamstabilizing effect of different agents on the incorporation of the expansion ratio and foam stability,prepared two excellent properties of concrete foaming agents, i.e., GL-1and GL-2.Researchshows that: GL-1foaming agent preparation showed high stability in the air, but the performanceis influenced by the outside temperature changes greatly. GL-2foaming agent at a temperature of5~45℃, still maintains its high stability, strong adaptability to the road construction conditions,and exquisite foam uniform, glossy, foaming multiple of42.2times,1h secretion of water andsedimentation distance are16.3ml and1.3mm;(2) Different effects of water-cement ratio, fly ash, sand and fiber content of the foamconcrete performance under different dry density level to compressive strength, water absorption,thermal conductivity and dry shrinkage value of performance indicators, systematic research.Research shows that: in the water binder ratio of0.44, fly ash instead of cement content of30%,the optimal600class properties of foam concrete preparation,28d compressive strength of4.14MPa. The W/C ratio of0.42, cement-sand ratio of1:1.8, water reducing agent dosage of1.2%,to prepare the1000foam concrete28d compressive strength of up to4.54MPa, the largestinfluence on the strength of the sand content. The W/C ratio0.58, fiberscontent0.10%prepared400foam concrete, compressive strength of7d and28d were0.76MPaand1.32MPa, thermal conductivity of0.072W/(m K), dry shrinkage of0.98mm/m, foamconcrete strength index prepared under different dry density can satisfy the requirements of thebase and subbase of different grade highways. (3) The different dry density, water-cement ratio and cement-sand ratio of pore foam concretestructure was observed by using the digital microscope, was obtained through formula derivationand calculation of different dry density, water-cement ratio concrete foam porosity, and usingImage J image analyzing software of its average pore size measurement, research shows that: withthe increasing of levels of dry density, pore diameter and the porosity decreases, the sand contentis greater, more obvious on the pore structure of destruction.(4) Combined with compressive strengths of foam concrete at28d, porosity and pore size ofthe data, using Griffith fracture mechanics of composite materials and theory as the foundation,carries on the analysis and the quantitative relationship between the modified foam concretestrength and pore structure, and the corresponding mathematical model is established, whichreveals the relationship between the foam concrete strength and porosity and pore size.