SiO2气凝胶/发泡水泥基复合材料的微观结构及性能

Microstructure and Properties of SiO2 Aerogel/Foam Cement-based Composites

采用外掺法制备了SiO2气凝胶/发泡水泥基复合材料,并系统研究了复合材料的微观结构、导热系数以及稳泡剂、水胶比、H2O2添量、温度、SiO2气凝胶添量对复合材料密度和抗压强度的影响。研究结果表明,疏水性气凝胶颗粒均匀分散在发泡水泥孔壁上且使得水泥水化产物中针状物质增多,片状生成物之间连接紧密性降低。SiO2气凝胶添量为1.5wt%时,稳泡剂添量为0.4wt%,水胶比为0.60,H2O2添量为4.0wt%,温度区间为35~45℃,按此配比所得复合材料密度较低,抗压强度较高。固定发泡水泥料浆用量,随着气凝胶添量的增加,复合材料发泡高度、导热系数降低,密度、抗压强度增加。

SiO2 aerogel/foam cement-based composites had been prepared by the external additive method.Subsequently,not only the microstructure and thermal conductivity of the composites but also the effect of foam stabilizer,water-binder ratio,H2O2 content,temperature and SiO2 aerogel content on the density and compressive strength of composites were systematically studied.The results show that the hydrophobic aerogel particles are uniformly distributed on the pore walls of the foam cement,which make the content of needle-like substances in the cement hydration products increase and then make the connection tightness between the sheet-like products reduce.When the content of SiO2 aerogels is 1.5wt%,the resultant composite with foam stabilizer content of 0.4wt%,water-binder ratio of 0.60,H2O2 content of 4.0wt%and the temperature range of 35-45℃,the foam cement composite has a lower density and a higher compressive strength.When the content of foam cement slurry is fixed,the foaming height and thermal conductivity of the composites decrease with the increase of aerogel content;conversely,the density and compressive strength of the composites increase with the increase of aerogel content.