混凝土早期变形与开裂敏感性评价

温度变形和自生变形是硬化混凝土在初龄期两种最主要的变形。温度变形是由水泥水化热和环境温度变化引起的变形，自生收缩变形是水泥水化导致的自干燥收缩变形，这两种变形对混凝土早期开裂敏感性的影响与混凝土的孔结构有关，而孔结构与混凝土硬化过程的温度水平及温度历程密切相关。试验表明，掺硅灰的混凝土具有较高的早期抗拉强度，而掺粉煤灰的混凝土具有更好的徐变应力松弛能力，抗裂性能较好，不同温度历程下混凝土热膨胀系数的准确测定对应力分析十分重要。

DEFORMATION AND CRACK SENSITIVITY EVALUATION OF CONCRETE IN EARLY AGE

Temperature deformation and autogenous deformation are the two major forms of deformation of hardening concrete in early age. Temperature deformation results from hydration heat of cement and variation of ambient temperature while autogenous deformation is a self-drying contraction caused by cement hydration. The impacts of the two deformations on crack sensibility of early concrete are related to concrete pore structure which is in close relation to the level and course of temperature in concrete hardening. Test demonstrates that the concrete mixed with silicon ash has higher early tensile strength while the concrete added with coal ash has better capability of creeping stress relaxation and good crack resistance. Accurate measurement of concrete expansion coefficient under different temperature courses is vital for stress analysis.