掺海绵多孔水泥混凝土力学和降温性能

Mechanical and temperature reduction properties of porous concrete with addition of sponge

为研究海绵掺量对多孔混凝土性能的影响,采用水泥、硅灰、4.75~9.5mm粗集料和海绵,配制了海绵含量分别为0、0.15%、0.20%、0.25%、0.30%、0.35%、0.40%、0.45%、0.50%、0.55%的海绵水泥混凝土混合料,压实成型试件后,进行了强度、吸水能力、蒸发时间、降温性能以及抗冻性试验。试验结果表明：当海绵含量小于0.50%时,掺入海绵对试件强度无明显影响,抗压、抗折强度最大值分别可以达到20.7MPa和2.47MPa,继续增加海绵含量强度呈下降趋势;当海绵含量为0.45%时,吸水能力最强,为0.144g/cm3;在相同环境温度下,水分蒸发与吸水能力密切相关,吸水较多的试件能够在较长的时间里维持较高的蒸发量,利于降温;在最高气温为37.4℃的测试条件下,海绵含量为0.45%的海绵水泥混凝土表面最高温度分别比沥青混凝土和普通水泥混凝土降温7.6℃和4.9℃;此外由于内部存在水分,海绵水泥混凝土在冻融后强度会有所下降,但不明显。

In order to study the influence of sponge addition on the properties of porous concrete,cement,silica fume,4.75-9.5mm coarse aggregates and sponge were mixed to made specimens in the lab.The addition of sponge were 0,0.15%,0.20%,0.25%,0.30%,0.35%,0.40%,0.45%,0.50%,and 0.55%respectively.Then the compressive strength,tensile strength,water absorption capacity,evaporation time,cooling performance and frost resistance were investigated.The results indicated that when the sponge addition is less than 0.50%,the specimens strength of cement concrete with addition of sponge did not change significantly and the maximum values of compressive strength and flexural strength could achieve to 20.7MPa and 2.47 MPa respectively.When the sponge addition increased continuously,the strength of specimens tended todecrease;when the sponge addition was 0.45%,the water absorption capacity of specimens was the strongest,and the value was 0.144g/cm3;at the same ambient temperature,water evaporation performance of cement concrete with addition of sponge is closely related to its water absorption capacity,the more water specimens absorbed,the longer time specimens maintained with higher evaporation and this could help to reduce surface temperature of specimens;when the maximum air temperature was 37.4℃,the surface temperature of specimen with 0.45%sponge addition was lower than that of asphalt concrete and normal cement concrete specimens and the reductions were 7.6℃and 4.9℃respectively.Due to the effect of water inside the specimens,compressive strength of the concrete with addition of sponge decreased slightly after frost resistance freezing and thawing test.4tabs,9figs,13 refs.