减缩剂对泡沫混凝土收缩的影响研究

发布时间：2019-05-12 04:37

【摘要】：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7 d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。
[Abstract]:In order to solve the problem of cracking of foam concrete due to shrinkage, when the ratio of water to cement is 0.33 and 0.50, the dry shrinkage value and self-shrinkage value of foam concrete are measured, combined with mercury injection method, nitrogen adsorption method and XRD. The effects of shrinkage reducing agents (S1 and S2) on pore structure, dry shrinkage and autoshrinkage of A08 foam concrete were studied. The results show that the water loss and dry shrinkage of foam concrete are mainly concentrated within 7 days, and when the ratio of water to cement is 0.33, the dry shrinkage value and self-shrinkage value of foam concrete can be reduced by 55.3% and 48.9% respectively. When the ratio of water to cement is 0.50, the shrinkage reducing agent can reduce the dry shrinkage of foamed concrete by 59.1% for 28 days. Under the condition of isolation from the environment, the foam concrete has the phenomenon of slight expansion. When the ratio of water to cement is 0.33 and 0.50, the number of pores in foam concrete is reduced by adding S1. When the water-cement ratio is 0.33, the addition of S _ 2 increases the number of large pores about 30 nm and decreases the number of small pores, while when the ratio of water to cement is 0.50, it is beneficial to the formation of small pores less than 4 nm.
【作者单位】：四川省非金属复合与功能材料重点实验室-省部共建国家重点实验室培育基地;西南科技大学;
【基金】：国家科技支撑计划资助项目(2011BAE14B05,2012BAJ20B04)
【分类号】：TU528.2

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