| The super-light foamed concrete with dry density less than 250kg/m3 was prepared by chemical foaming method. The effects of w/c, H2O2 dosages, mineral admixture, fibers and polymer emulsions dosages on the physical mechanical properties and pore structure were studied. It is possible to provide technical guidance and theoretical support for the production by exploring the relevance of pore structure and physical properties. The results as follows:The suitable w/c and H2O2 dosages range from 0.44 to 0.52 and 6% to 7% respectively and the physical mechanical properties of foamed concrete have strength higher than 0.2MPa, density lower than 250kg/m3 and water absorption smaller than 10%. The porosity of foamed concrete are higher than 74.05%, average pore sizes are more than 2mm, and the roundness values are close to 1.The pore structure and properties of foamed concrete were regulated by adding slag powder, fly ash and iron tailings powder. The results show that the suitable slag powder, fly ash and iron tailings dosages are respectively 15%~30%, 10%~20% and 10%~30%. Within those suitable dosages, the porosity is lower than 74.05%, average pore sizes are less than 2 mm, pore sizes more than 3 mm were few, and the roundness values are closer to 1.The pore structure and properties of foamed concrete were adjusted by adding different specifications fibers. The results show that the suitable dosages of four kinds of fibers are 0.1%~0.7%, 0.5%~1.0%, 0.5%~0.7% and 0.1%~0.5% respectively. The strength of the foamed concrete mixed with fibers is nearly three times higher than the control sample. The porosity is lower than 74.05%, the ratios of pore sizes which locate at 0 mm to 2 mm, are up to 60%, average pore sizes are less than 2 mm, and the roundness values change little.The pore structure and properties of foamed concrete were conducted by adding SWE-10, SWE-18 and 991# which making the thermal conductivity between 0.065 to 0.080 W(m·k). The results show the suitable dosages of emulsions are 0.5%, 0.3%, and 0.5%. Compared with control sample, the strength of foamed concrete added emulsions increases nearly 1 time. The porosity is less than 74.05%, the ratios of pore sizes locate between 0 to 2 mm, are up to 80%, the pore sizes more than 3 mm do not exist, average pore sizes are less than 1.8 mm, and the roundness values are closer to 1. |
