钙质骨料混凝土抗压强度的高温损伤机理

Damage Mechanism of Compressive Strength of Calcareous Aggregate Concrete after Elevated Temperature

研究了高温后钙质骨料混凝土（C30）残余抗压强度的变化规律，同时借助热重试验、扫描电镜试验和压汞试验对与钙质骨料混凝土同水灰比和经历相同高温冷却条件处理的硬化水泥浆（HCP）进行了微观试验研究．结果表明：HCP在中低温段（100～300℃）的二次水化反应对钙质骨料混凝土在该温度区段的残余抗压强度有很大影响．钙质骨料混凝土高温后残余抗压强度和高温后HCP孔隙率之间具有良好的负相关性．

The variation of residual compressive strength of C30 calcareous aggregate concrete after elevated temperature was studied. Microscopic investigation on hardened cement paste（HCP） which had the same water to cement ratio and the same process methods of heating and cooling with the concrete, was conduc- ted by thermogravimetric（TG） analysis, scanning electron microscopy（SEM） test and mercury intrusion porosimetry（MIP） test. The results indicate that the secondary hydration effect of HCP at medium and low temperatures（100 -300 ~C） has significant influence on the residual compressive strength of calcareous aggregate concrete at correspondent temperature interval. Meanwhile, the residual compressive strength of calcareous aggregate concrete has a good inverse correlation with the porosity of HCP after elevated temperature.