Experimental Study On Composite Self-insulation Concrete Blocks

Along with the work of energy efficiency in buildings and innovation in wall materials carrying out in our country, concrete hollow block has been vigorously promoted in China as an alternative solid clay brick in the wall material, because of its energy-saving and land-saving features. However, in recent years, some studies have shown that the thermal insulation effect of concrete hollow blocks can't meet the national requirements related to energy efficiency standards fully, and the concrete hollow block need to be modified. The composite self-insulation block in this article was injected the low-density foaming concrete into the concrete hollow block's cavity, and makes them become a new wall self-insulation block, so that it has good insulation properties, and can meet the energy-efficient building requirements of the wall materials.Based on the investigation and analysis of related research and literature, through the research on foaming concrete composition and properties, three kinds foaming concrete of different density and strength were obtained, filled them into the concrete hollow block, constitute the composite self-insulation concrete blocks, further, through the research of its mechanical and thermal experiments, we compare and analyze it with the performance of blocks unfilled with low-density foaming concrete and obtain the following conclusions :(1)Dilution ratio of foaming agent and stirring speed of foaming machine affect the quality of foam significantly, the dosages of foaming agent, the water-cement ratio of concrete and the dosages of water-reducing agent have an important impact on compressive strength, dry density and water absorption of foaming concrete.(2)Filling with low-density foaming concrete could increase flexural strength of the composite block and shear strength of masonry significantly. The greater dry density of foam concrete filled in the composite insulation blocks is, the stronger its flexural performance and shear performance are.(3)The measured thermal performance indicators of composite self-insulation block which was developed in this experiment can meet the national requirements related to energy efficiency standards. The thermal insulation performance of double hole blocks was better than the single row of holes masonry's. The lower dry density of foam concrete filled in the composite insulation blocks was,the better thermal insulation properties of the composite self-insulation blocks were.(4)The calculation formula about compressive strength of concrete small blocks, under the existing guidelines, was suitable to calculate compressive strength of the composite block filled with low-density foaming concrete in this study, however, when its shear strength was calculated according to strength formula under the existing guidelines, measured data of double hole composite self-insulation blocks situates in the unsafe side, we suggest the coefficient k5 about block types in the calculation formula under the existing guidelines should be modified , this article suggested that the coefficient k5 equal to 0.055.