【摘要】 采用100 mm×100 mm×13 mm的板状试件，研究了HVFA-SHCC材料高温后的弯曲性能，探讨不同温度和不同冷却方式对其破坏模式、残余弯曲强度、弯曲应力挠度曲线和弯曲韧性的影响。采用扫描电镜观察HVFA-SHCC材料的微观结构，揭示其破坏机理。结果表明：当温度为100℃时，温度对HVFA-SHCC试件的弯曲性能及质量损失影响较小。随着温度的升高，HVFA-SHCC试件内部微结构不断劣化，质量损失率逐渐增大，破坏模式由延性破坏转变为脆性破坏，残余弯曲性能劣化严重。尤其是800℃时，试件的质量损失率达15.5%，残余弯曲强度仅为常温状态的30%，弯曲耗能为常温状态的0.74%；浸水冷却试件的残余弯曲强度和弯曲韧性有一定程度的提高。更多还原

【Abstract】 Experimental investigations on the residual flexural behavior of strain hardening cementitious composites with high volume fly ash(HVFA-SHCC) subjected to elevated temperature were carried out.Platen specimens with dimension of 100 mm ×100 mm×13 mm were exposed to different temperatures.Failure modes,residual flexural strength and flexural toughness were analyzed after two cooling methods.Scanning electron microscope(SEM)was used to observe the microstructure of the HVFA-SHCC specimens at meso-scale level and obtain the degradation mechanism.Experimental results indicate that when the temperature is equal or lower than 200 ℃,the temperature has little effect on the residual flexural behavior and mass loss of HVFA-SHCC specimens.With the increase in the temperature,the internal microstructure of HVFA-SHCC specimens becomes loose,the mass loss rate increases gradually,the failure mode changes from ductile failure to brittle failure,and the residual flexural performance deteriorates seriously.Especially at 800 ℃,the specimen shows obvious strain softening behavior.And the mass ratio,the average residual flexural strength and the flexural toughness of the specimens are 15.5%,30% and 0.74% of that at 20 ℃,respectively.Cooling method shows little effect on the failure mode,but great influence on the flexural properties of the specimens.The residual flexural strength and flexural toughness of specimens are improved when cooled in water.更多还原