建筑渣土对泡沫混凝土孔结构与传热的影响

Effects of Construction Residue Soil on Pore Structure and Heat Transfer of Foamed Concrete

为促进建筑渣土在建筑保温领域的资源化利用,以建筑渣土料浆为成孔介质,取代预制泡沫,辅以物理发泡工艺,制备了400 kg/m^(3)和600 kg/m^(3)密度等级泡沫混凝土,研究了渣土对其孔结构及传热行为的影响。结果表明:密度400 kg/m^(3)泡沫混凝土的渣土料浆体积取代率从0%增至60%,导热系数从0.09 W/(m·K)降至0.07 W/(m·K);密度600 kg/m^(3)泡沫混凝土的渣土料浆体积取代率从0%增至100%,导热系数从0.14 W/(m·K)降至0.10 W/(m·K);渣土料浆的掺入细化了泡沫混凝土孔结构,增加了微观孔隙率。由于孔结构细化带来传热路径延长、气相导热系数与多孔基体导热系数下降,泡沫混凝土保温隔热性能提升。

To promote the resource utilization of construction residue soil in the field of building insulation,foamed concrete with density grades of 400 kg/m^(3) and 600 kg/m^(3) was prepared by using construction residue soil paste as the pore-forming medium to replace prefabricated foam and applying physical foaming process.The influence of construction residue soil on the pore structure and heat transfer behavior of foamed concrete was investigated.The results show that for foamed concrete with a density of 400 kg/m^(3),the volume replacement rate of construction residue soil paste ranges from 0%to 60%and the thermal conductivity decreases from 0.09 W/(m·K)to 0.07 W/(m·K).For foamed concrete with a 600 kg/m^(3) density,the volume replacement rate of construction residue soil paste ranges from 0%to 100%and the thermal conductivity decreases from 0.14 W/(m·K)to 0.10 W/(m·K).The addition of construction residue soil paste refines the pore structure of foamed concrete and increases the microscopic porosity.The refinement of the pore structure is attributed to the elongation of heat transfer paths and the decrease of thermal conductivity of the gas-phase and porous matrix,which improves the thermal insulation performance of foamed concrete.