Experimental Study On Effects Of Steel,Steel Fiber And Fly Ash On Shrinkage And Creep Of Early Age Concrete

The shrinkage and creep of concrete is one of the main factors affecting the safety and durability of concrete structures.At present,most researches on shrinkage and creep of concrete are carried out on mature concrete,but there is a lack of research on shrinkage and creep of concrete in early age.In order to further grasp the law of shrinkage and creep of concrete in early age,combined with the National Natural Science Foundation of China,“Study on the Long-Term Tensile and Compression Creep Characteristics of High-Strength Concrete and the Calculation Method of Nonlinear Creep Stress of Its Structure”(Project No.51408218),The experimental study on shrinkage and tension/deformation of early age concrete was carried out.The main contents and conclusions are as follows:(1)Shrinkage and tensile/compression tests were carried out on early age concretes with different reinforcement conditions(0,1% and 2%).The results show that the reinforcement inhibits the shrinkage and tensile/compression of the early age concrete,and the greater the reinforcement ratio,the smaller the concrete shrinkage and the tensile/compression creep.The measured compression creep and the tensile creep under the same parameters were compared and analyzed.According to the test results and the existing related references,the influence coefficient of the reinforcement on the shrinkage of the early age concrete,the influence coefficient of compression and tensile creep are proposed.(2)The shrinkage and tensile/compression tests of early age concrete with different steel fiber content(0,1% and 2%)were carried out.The results show that the steel fiber inhibits the shrinkage and tensile/compression of the early age concrete,and the larger the steel fiber content,the smaller the concrete shrinkage and the tensile/compression creep.The measured compression creep and the tensile creep under the same parameters were compared and analyzed.According to the test results and the existing related references,the influence coefficient of steel fiber content on the shrinkage of early age concrete,the influence coefficient of compression and tensile creep are proposed.(3)The shrinkage and tensile/compression tests of early age concrete with different fly ash content(0,10% and 20%)were carried out.The results show that fly ash reduces the shrinkage of early age concrete,but increases the tension/pressure creep.The measured compression creep and the tensile creep under the same parameters were compared and analyzed.According to the test results and the existing related references,the influence coefficient,compression and tensile creep of the fly ash on the early age concrete are proposed.