Research progress on shrinkage of ultra high performance concrete
Shrinkage is the main cause of early cracking of ultra high performance concrete(UHPC).The development law,testing method,control method and shrinkage mechanism of UHPC were summarized.The results show that the shrinkage of UHPC is mainly composed of autogenous shrinkage and drying shrinkage.Autogenous shrinkage usually accounts for 78.6％～90.0％of the total shrinkage,which mainly occurs in the early stage and tends to be stable in the later stage.Thermal curing and combined curing can eliminate the shrinkage strain of UHPC in the later stage,due to promoting cement hydration and pozzolanic reaction of admixtures,and improving pore structure.The capillary tension theory can well explain the mechanism of UHPC autogenous shrinkage from the perspectives of relative humidity,pore structure,self-stress,interface structure and hydration degree.The measurement method of UHPC shrinkage is main focused on the laboratory,and it is necessary to develop a shrinkage deformation measurement technology of UHPC used in practical engineering.In this way,long-term monitoring,real-time data transmission,crack prediction and early warning can be realized,which is very important for the real-time maintenance and engineering crack prevention guidance of large-scale UHPC structures.
NETL
NSTL
万方数据
