Experiment Research On Bonding Properties Between Combined Aggregate Concrete And Steel Bar

Combined aggregate concrete is a kind of transitional concrete.It is use of lightweight aggregate instead of part of the ordinary coarse aggregate and the density of combined aggregate concrete was between ordinary concrete and lightweight aggregate concrete. Compared with ordinary concrete, it has lighter weight and good durability characteristics;Compared with the lightweight aggregate concrete, it has higher strength and elastic modulus ratio, and has smaller shrinkage deformation and creep deformation. According to these characteristics, combined aggregate concrete is generally used for large span concrete bridge and marine concrete oil platform.For better reinforcing steel bar to better service in engineering practice, the main research work that focuses on the bonding performance of the combined aggregate concrete and reinforcing steel bar are shown as follows:1. The test program is design by changing the water cement ratio and vo lume fraction of light aggregate, and 18 sets of pull out specimen and cube co mpressive strength test block are made.2. Through experiments, the damage characteristics of the combined aggregate concrete are analyzed.3. Through experiments,the bond strength, compressive strength of steel bar and concrete are tested, and the effect of two factor -water cement ratio and volume fraction of light aggregate- on bond strength and compressive strength is studied.4. Through the experiment, the water cement ratio and the volume fraction of light aggregate on the distribution of bond stress along the length of the reinforcement are studied.5. Based on experimental test,the formula for calculation of the combine aggregate concrete ultimate bond strength and tensile strength is proposed, meanwhile, comparative analysis of ordinary concrete formula has carried on.