Study on the flexural behavior of HVFA-SHCC after high temperatures
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.
high temperaturestrain hardening cementitious composites with high-volume fly ash(HVFA-SHCC)cooling methodmicrostructureresidual flexural strengthflexural toughness
万方数据
维普
