建筑垃圾复合粉体材料对混凝土抗冻性能的影响∗

摘要

Combined with concrete macro-performance tests,impacts of construction waste composite powder material on concrete strength and anti-frost performance were studied by using DSC-TG,scanning electron microscope (SEM)and mercury intrusion porosimetry (MIP).The results showed:C30 concrete had the highest strength and the best anti-frost performance when the dosage of construction waste composite powder material was 30%;the specimens were easy to failure under low-medium saline solution condition.Construction waste composite powder material can re-duce the content of Ca(OH)2 for its filling effect and pozzolanic effect,facilitating the formation of hydrated calcium silicate gel with low basicity,which has better performance and better micro-structure than Ca(OH)2 ,and resulting in proper concrete pore structure and pore gradation,which will improve concrete strength and anti-frost performance.%借助 DSC-TG、扫描电镜和压汞实验,并结合混凝土宏观性能实验,研究了建筑垃圾复合粉体材料对C30混凝土力学强度及抗冻性能的影响机理。结果表明：建筑垃圾复合粉体材料掺量为30%时,C30混凝土强度及抗冻性能最优；中低盐溶液浓度时,试件更容易发生盐冻腐蚀破坏。建筑垃圾复合粉体材料由于其填充效应及火山灰效应减少了取向性较强的 Ca(OH)2含量,生成性能较优、微观结构较为致密的低碱度水化硅酸钙凝胶,使得混凝土内部较为致密,孔结构和孔级配趋向合理,宏观上表现为混凝土强度及抗冻性能的提高。