Influence Of Curing Condition On The Properties Of Concrete At Early Ages

By taking the pumped concrete which is used in large quantity at the scene of construction for the object of study,the properties of strength,modulus of elasticity and shrinkage of concretes under different curing conditions were discussed.The primary parameters of experiment in this study are as follows:three kinds of water -cement ratios of concrete(0.35,0.45 and 0.60);four kinds of curing conditions of concrete:summer temperature,winter temperature,room curing and water-curing.The result of the experiments indicated that:the curing conditions affected the early age performance of concrete greatly.The strength,modulus of elasticity and shrinkage of concrete developed especially fast before 3 days and gradually slowed down after 7 days.The curing condition under the high temperature in summer reduced the concrete strength in the later period.Reducing the water-cement ratio could be helpful to reduce the negative effects which were caused by the curing under high temperature.The maturity concept was used to evaluate the strength of concrete under different curing temperatures,and the relation expression between the strength and maturity of concrete under winter curing was obtained by regression analysis. Under the winter curing,the performance of concrete was lower than that under other curing conditions obviously.The lower the relative humidity of the air was,the higher the temperature and the greater the shrinkage of concrete were.The sealed curing condition can reduce the shrinkage of concrete greatly in the early period.The shrinkage of concrete which was sealed for 7 days was very small Based on the experimental data,the formula for estimating shrinkage of concrete under the summer conditions was obtained by regression analysis in this paper.Comparing the other formulas,the formula present in this paper can evaluate the early shrinkage of concrete more effectively.