高性能混凝土早期抗裂研究

为减小高性能混凝土早期开裂,利用非接触测量技术,测量了高性能混凝土早期自生及单面干燥条件下的收缩,研究了减缩剂、聚丙烯纤维等几种作用机理不同的物质对高性能混凝土早期自生及干燥收缩的影响．在此基础上,利用板式混凝土早期收缩开裂试验架,对高性能混凝土进行了约束试验,研究了减缩剂、减缩剂+聚丙烯纤维等对高性能混凝土早期抗裂的作用．结果表明:减缩剂、聚丙烯纤维、减缩剂+聚丙烯纤维及渗透结晶防水涂料均有减缩抗裂效果,其作用大小为渗透结晶防水涂料>减缩剂>减缩剂+聚丙烯纤维>聚丙烯纤维．

Research on anti-cracking of high performance concrete at early age

In order to induce cracking of high performance concrete (HPC) at early age. a non-contacting measurement technology was adopted. Autogenous shrinkage and shrinkage with single side in dry environment of HPC were tested by using the measure technology. The effects of some materials of different mechanism of actions, for example shrinkage reducing agent (SRA), the polypropylene fiber(PPF), etc. on autogenous shrinkage and shrinkage of HPC with single side in dry environment were discussed. Based on the results of shrinkage tests, the slab specimens of HPC were restrained by utilizing the steel frame and the effects of SRA, SRA + PPF, etc. on anti-cracking of HPC in dry environment were discussed. The whole anti-cracking effects of these ways, which can both reduce autogenous shrinkage and cracking of HPC, are obtained from high to low: cement-base capillary crystalline waterproof (CCCW), SRA, SRA + PPF and PPF.