多孔玄武岩粗骨料HPC的制备和收缩性能研究OACSTPCD

In order to solve the problems of high viscosity,difficult mixing and poor durability of high performance concrete(HPC)caused by large water absorption rate and fast early water absorption of porous basalt coarse aggregate,additional water consumption was introduced to prepare pre-wetted aggregate before preparation.The effects of different additional water consumption on workability,mechanical performance,shrinkage performance,pore structure and microstructure of porous basalt concrete were studied.And the performance of porous basalt concrete was compared with that of ordinary crushed stone concrete.The results show that when the additional water consumption is 4％or 6％(calculated by mass fraction of porous basalt coarse aggregate),the HPC with C60 compressive strength grade,excellent workability and low shrinkage can be obtained.Compared with ordinary gravel concrete,pre-absorbed porous basalt can significantly reduce the autogenous shrinkage of HPC,and has little effect on compressive strength.The self-shrinkage rate decreases with the increase of additional water consumption,and its development is divided into four stages of rapid growth,short-term expansion,slow growth and stabilization.The water-bearing basalt has internal curing effect,which can refine the pore structure in the later stage of hydration,improve the compactness of the interfacial transition zone and reduce the cracking risk of HPC.