【摘要】 对经过轴向受压循环加载后的粉煤灰高性能混凝土进行了自然吸水性试验研究。试验现象验证了轴压作用下,混凝土试件内部微观结构的变化规律:裂纹稳定阶段(I阶段),裂纹汇合阶段(I阶段),裂纹成核阶段(III阶段);吸水高度h与t1/2的关系近似指数函数;在低载荷等级作用下(第I阶段),粉煤灰对降低混凝土损伤程度和吸水性能影响较大;在高等级载荷作用下(第II和III阶段),粉煤灰的影响效果减弱,载荷等级的影响占主导地位;20%的粉煤灰掺量在第I、II和III阶段内均显著改善了混凝土的力学性能,减小了混凝土在载荷作用下的损伤程度;通过数据分析及拟合得到了吸水高度h随粉煤灰掺量n,载荷等级m和时间t的变化关系式,为工程应用提供参考。更多还原

【Abstract】 The natural water absorption experimental study of high performance concrete mixed with fly ash under cyclic uniaxial compression was carried out.The experimental phenomena verifies the change law of internal microstructure of concrete specimens under axial compression,crack stability stage(stage I),crack convergence stage(stage I),crack nucleation stage(stage III).The relationship between water absorption height h and t1/2 is approximate to exponential function.Under the action of low-grade load(stage I),fly ash has great influence on reducing the damage degree and water absorption of concrete.Under the action of high-grade load(stage II and III),the effect of fly ash is weakened,and the effect of load level is dominant.The results show that 20% fly ash can significantly improve the mechanical properties of concrete and reduce the damage degree of concrete under load.The relationship between water absorption height h,fly ash content n,load grade m and time t is obtained,which provides reference for engineering application.更多还原