关键词:  , 混凝土；塑性收缩；蒸发；裂缝

Abstract: The effect of varying environmental conditions in the time of casting and curing on the properties of fresh and hardened high strength concrete(HSC) was evaluated. The method of artificial imitation in the lab was adopted and the influences of air temperature（T）, wind velocity（V）, and relative humidity（RH） on plastic shrinkage, compressive strength, and pore structure of concrete were investigated. The data developed in this study are represented as follows: Exposure conditions in the time of casting significantly affect the properties of both fresh and hardened concrete. The rate of water evaporation, shrinkage strain and the area of cracks increase with increasing
exposure temperature and wind velocity, and with decreasing relative humidity.
Plastic shrinkage cracks occur earlier in the concrete specimens exposed to elevated temperature and low relative humidity than that exposed to low temperature and high humidity. Similarly, cracks happen earlier in the concrete specimens exposed to windy conditions than those exposed to no wind. Casting and curing of concrete at elevated temperature would decrease its compressive strength. The volume of total pores in the concrete specimens cast and cured at 40℃ is more than that at 30℃. It is certainly affected by changed wind velocity and relative humidity on compressive strength .