Dynamic compression performance of carbon fiber reinforced lightweight aggregate concrete after high temperature
There is a lack of research on the mechanical properties of carbon fiber reinforced lightweight aggregate concrete after high temperature.Considering the damage to the structure caused by the impact and explosion load accompanied by fire,the dynamic compression tests on lightweight aggreg ate concrete(LWAC)were carried out by using split Hopkinson pressure bar(SHPB)device with a diameter of 74 mm.The effects of temperature and carbon fiber content on the dynamic compression performance of LWAC were researched,and the effect of high temperature on the microstructure of LWAC was revealed by SEM.The results show that the increase of carbon fiber content improves the static compressive strength of LWAC,while high temperature has a deterioration effect on the static compressive strength of LWAC,and fiber incorporation can prevent the deterioration of high temperature strength to a certain extent.The stress-strain curve of LWAC tended to be flat with the increase of temperature,and the dynamic compressive strength decreased while the peak strain and ultimate strain increased.The dynamic compressive strength,peak strain and ultimate strain all increased first and then decreased with the increase of carbon fiber content.The DIF of LWAC specimens increased linearly with the increase of strain rate under different temperature and carbon fiber content.The rate sensitivity of ordinary LWAC samples was higher than that of carbon fiber LWAC specimens.The high temperature initially improved the internal microstructure of LWAC,but with the continuous increase of temperature,the internal microstructure of the sample seriously deteriorated.
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