HCSA补偿收缩混凝土收缩裂缝自愈合性研究

对掺加高性能混凝土膨胀剂HCSA的水泥净浆水化产物进行X射线衍射、扫描电镜与差热分析,同时研究了由其制备的补偿收缩混凝土裂缝自愈性能。结果表明,与空白样相比,掺HCSA膨胀剂水泥净浆水化产物中具有更多的Ca(OH)_2。即使早期未进行水养护,遇水后掺HCSA膨胀剂的补偿混凝土也会产生较大的膨胀应力,从而具有比普通混凝土更强的裂缝自愈合能力。HCSA混凝土裂缝愈合的主要驱动力是膨胀应力,其次是结晶沉淀修复。掺HCSA膨胀剂的补偿收缩混凝土裂缝处析出物质主要是碳酸钙。此外,工程实践证明,地下工程采用掺加HCSA膨胀剂的补偿收缩混凝土具有良好的自愈合性。

Experimental Study on Thermal Stress of Concrete with Different Expansive Minerals Using a Temperature Stress Testing Machine

In order to compare the compensation effect of expansive materials with different mineral sources on the temperature stress of concrete,we investigated the temperature stress of concrete when adding calcium sulfoaluminate type expansive materials(CSA)or CaO and calcium sulfoaluminate mixed type expansive materials(HCSA)at different temperatures by temperature-stress testing machine(TSTM)considering the influence of temperature history on the expansion.The experimental results show that the expansion characteristics of the two kinds of expansive materials with different mineral sources significantly vary.When adding expansive materials,the growth rate of compressive stress during the heating stage increases obviously,the maximum compressive stress is higher,while the decline rate of tensile stress in the late cooling stage becomes slow,and finally cracking temperature decreases.It is proved that concrete with HCSA has lower cracking temperatures and better temperature shrinkage compensation effect.Therefore,it is rational to choose HCSA when preparing concrete with high expansion energy to reduce thermal cracking.

混凝土抗侵蚀防腐剂性能研究

采用工业废渣、活性激发组分及阻锈组分制备混凝土抗侵蚀防腐剂,以中、高抗硫酸盐水泥为对比样,研究了混凝土抗侵蚀防腐剂的化学组成、力学性能与耐蚀性能。结果表明,混凝土抗侵蚀防腐剂的抗蚀性能介于中、高抗硫酸盐水泥之间,可以显著提高混凝土的密实性与抗侵入性,具有良好的抗盐类侵蚀功能。氯离子含量仅为0.03%,28d抗压强度比104%,28d膨胀率0.38%,抗蚀系数1.12,膨胀系数1.10,氯离子扩散系数比0.56。