为解决泡沫混凝土因收缩而开裂的问题,在水灰比为0．33和0．50的情况下,通过测定泡沫混凝土的干缩值和自收缩值,结合压汞法、氮吸附法及 XRD等测试手段,研究了减缩剂(S1与 S2)对 A08级泡沫混凝土孔结构、干缩及自收缩的影响.结果表明,泡沫混凝土失水和干缩主要集中在7d 以内；当水灰比为0．33时,减缩剂可使泡沫混凝土28 d干缩值和自收缩值降低55．3％和48．9％；当水灰比为0．50时,减缩剂可降低泡沫混凝土28 d干缩59．1％,与环境隔离的条件下,泡沫混凝土存在微膨胀现象；水灰比为0．33和0．50,掺入 S1使泡沫混凝土毛细孔数量减少；水灰比为0．33时,S2掺入使30 nm 左右的大的毛细孔数量增多,小的毛细孔数量减少,而水灰比为0．50时,利于小于4 nm的小的毛细孔形成.
To prevent cracking caused by shrinkage,pore structure,drying shrinkage and autogenous shrinkage of foamed concrete with SRA (S1 and S2),were studied by testing drying shrinkage and autogenous shrinkage and analyzed by MIP,BET,XRD,when W/C were 0.33 and 0.50.The result showed that water loss and drying shrinkage of foamed concrete appeared mostly in the early 7 d.The decreased values of drying shrinkage and au-togenous shrinkage of 28 d on foamed concrete were up to 55.3% and 48.9%,when W/C was 0.33.With W/C 0.50,drying shrinkage of 28 d on foamed concrete decreased by 59.1% to the most.And tiny expansion of foamed concrete happened when it was isolated from outside.The number of capillary pores in foamed concrete was decreased by adding S1 with W/C 0.33 and 0.50.When W/C was 0.33,the number of small capillary pores reduced by adding S2,but the big ones with the pore size of about 30 nm increased.When W/C was 0.50,S2 benefited to increasing the number of small capillary pores less than 4 nm.
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