Effect of silica fume and aggregate on high temperature resistance of concrete
When concrete is exposed to high temperature,cracks will occur when its constituent materials undergo different volume changes and damage,resulting in the decrease of durability and mechanical properties,in which cementitious materials and coarse aggregates play an important role.The effects and morphology changes of strength loss of concrete after high temperature by adding 10％silica fume and using crushed stone and shale ceramsite are compared here.Creep under continuous load after high temperature is very important,so the effects of different aggregate types and loads on concrete creep are compared.The results show that the strength of concrete decreases obviously after 400℃,and the strength decrease increases with the addition of silica fume.The residual compressive strength of lightweight aggregate concrete is much higher than that of conventional concrete at high temperature,and there are fewer cracks due to the relief of thermal expansion stress.When the dead load is applied,the deformation of lightweight aggregate concrete below 500℃ is large,and the deformation of ordinary concrete is higher than that of lightweight aggregate concrete above 500℃.
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