Study On High Density Foam Concrete

Energy conservation and emission reduction is an essential national policy ofChina, and it is clearly required in the Twelfth Five-Year plan that “paying moreattention to saving energy and reducing emission to extend its range”. At present,building energy consumption accounts for about28%of the total entire society in ourcountry, and building heating energy consumption per unit area is2~4times as high asthe developped countries. Therefore, improving the building energy efficiency and itsthermal insulation property is imperative, and it is necessary to develop new typeenergy-saving building materials.Foam concrete can satisfy the requirement of building energy saving, with lightweight and superior properties, such as, excellent thermal insulation, high soundinsulation and fire resistance, nonflammability, good earthquake resistant ability andrecycling waste. So foam concrete has been widely used in construction heatpreservation, while it is seldom used in load bearing walls because of its low strength,big natural drying shrinkage and high water sorptivity, which have seriously restrictedits development and application.After referring to a lot of literatures related to foam concrete, the author carry out aseries of experimental study about high density foam concrete based on previousresearch. Firstly, verify the feasibility of this topic and put forward the system, densityrange and benchmark mix proportion of the foam concrete planned to research throughexploratory experiments. Secondly, confirm the mineral additives and research systemby comparing the properties of high density foam concrete with different additives,belonging to different system. Then, discuss the effect of raw material proportion inbenchmark mix proportion on the properties of high density foam concrete by singlefactor analysis method. On this basis, design an orthogonal test and carry out analysis ofvariance to confirm the significant degree as well as primary and secondary order of thefactors’ influence on high density foam concrete’s properties, choose the optimal levelof the factors and get the optimized mix proportion. Finally, examine the influence ofother factors, for example, cement grade, foaming agent’s dilution multiple, dosage ofpolycarboxylate superplasticizer, polypropylene fiber’s length and dosage on theproperties of high density foam concrete, prepare fiber reinforced high density foamconcrete, and research its performance. The research results show that:①Gypsum content has very great influence on28ddrying shrinkage value;②Plastic density has great effect on28d flexural strength anddrying shrinkage;③Cement proportion greatly influences on28d flexural strength;④Adding some polypropylene fiber in foam concrete slurry can significantly improveits drying shrinkage property as well as appropriately raise its strength;⑤The fiberreinforced high density foam concrete with high strength, low moisture content andwater sorptivity,25times freeze-thaw resistance, good work performance, small dryingshrinkage value and thermal conductivity coefficient, can be prepared by graduallyoptimizing the benchmark mix proportion and selecting raw materials;⑥Increasingthedry apparent density of foam concrete and preparing high density foam concrete is oneof effective measure to improve its properties;⑦Foam concrete is not only can be usedfor building insulation, but also can be expected to be used as bear heavy wall materials.