混凝土气密剂的制备与应用性能及其微观结构分

（中建西部建设新疆有限公司，新疆 乌鲁木齐  830000）

    摘要：采用预乳化种子乳液聚合法制备了混凝土新型气密剂。研究确定了气密剂的最优合成工艺为：乳化剂用量4.0%、单体滴加时间15 min、预乳化温度35 ℃、反应时间60 min。通过红外光谱、扫描电镜分析和水泥胶砂强度、压汞、混凝土力学性能、气泡间距系数测试结果表明：所合成的气密剂使水泥水化结晶由针尖状变为棒状，且使裂缝处生成贯穿结晶，增大胶砂试块密实度，延缓应力集中；当气密剂掺量为0.02%时，水泥胶砂试件的抗压强度提升1.5~3.0 MPa，混凝土气泡间距系数减小0.462 mm、气泡平均直径减小79 μm，有效提升了水泥基材料的力学性能和耐久性。

    关键词：气密剂；密实度；气泡间距；气泡直径

    中图分类号：TU528.042+.2        文献标识码：A        文章编号：1001-702X（2018）09-00

 

The preparation and properties of airtight agent for concrete and its microstructure analysis

BAI Guoqiang，LI Xiaowen，LU Xiao，CHEN Xu，LIU Yang

（China West Construction Xinjiang Group Co. Ltd.，Urumqi 830000，China）

  Abstract：In this work，the new-type airtight agent was prepared by pre-emulsified seed emulsion polymerization. The optimum conditions of polymerization are as follow：the dosage of emulsification agent was 4.0%，the drop time of monomer was 10 min，the polymerization was carried out at 40 ℃，the reaction time was controlled in 60 min. The results of infrared spectroscopy，scanning electron microscopy（SEM） analysis and cement mortar strength，mercury intrusion，concrete mechanical properties and bubble spacing coefficient test show that the synthesized air-tight agent makes the cement hydration crystal change from acicular crystal to rhabdolith，and penetration crystal is generated at the crack, increase the compactness of the mortar test block and delay the stress concentration. When the amount of airtight agent was 0.02%，the compressive strength of cement mortar specimen were enhanced 1.5~3.0 MPa，the bubble spacing factor of concrete were decreased 0.462 mm，and the average diameter of bubble were decreased 79 μm，which effectively improves the mechanical properties and durability of the cement-based material.

    Key words：airtight agent，compactness，bubble spacing factor，the average diameter of bubbles