The effect of recycled concrete powder on the volume stability of concrete was studied by using slab cracking test and dry shrinkage test,and the mechanism of recycled concrete powder on the microstructure of concrete was analyzed by scanning electron microscopy.The test results show that the recycled concrete powder admixture can delay the cracking time,reduce the cracking quantity and reduce the cracking degree of concrete.The cracking mode of concrete slab shows that the closer it is to the periphery of the slab,the more densely distributed the cracks are.The farther away from the sides of the slab,the fewer but the longer they cracks are.The recycled concrete powder can effectively reduce the dry shrinkage deformation of concrete,which is mainly related to the fact that the recycled concrete powder can compact the microstructure of concrete,reduce the pores of concrete,and improve the interface bonding degree of cement mortar and aggregate.
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