Study On High Strength And High Performance Concrete Applied To Steel Reinforced Concrete Structure And Its Damage Constitutive Relationships

Compared with reinforced concrete structure and steel structure, steel reinforced concrete structure has superior mechanical behaviour and good comprehensive benefit. It has alreadly become important development direction of structure system in this century, and will be applied more and more in public building and the bridge structure, etc. Various performance of composite structures is decided by performance of steel and concrete, so it is of great significance to seek for the high strength and high performance concrete (HSHPC) to replace normal concrete in steel reinforced concrete composite structure to guarantee two kinds of the material work better together, by which fulfilling sustainable development of composite structures.Up till now, the research of HSHPC was maked by many scholars in the world, but their common characteristics are all to aim at one or several components of concrete. Because concrete is a sort of compound material, the properties of each component and their interaction should be considered. By analysis of microscopic action mechanism and the change of microstructure, HSHPC applied to composite structures can be developed. Related to constitutive relationship for concrete, many models were put forward and they are of great difference. They maybe adapt to normal concrete but uncertain to HSHPC, so the constitutive relationship of HSHPC applied to composite structures should be researched.The paper takes HSHPC applied to steel reinforced concrete (SRC) composite structures as research object. The current domestic and overseas researches were reviewed, and the property of each component of concrete was analysed by theory of material microstructure and preliminary selection for raw material was made. The experiment was made to discuss the influence of the material performance of different composition ratio orprocessing parameters. As a result, the best combination condition and the best-mixed proportion were obtained. In the light of damage mechanics and statistics knowledge, the material failure mechanism was analyzed, and the damage constitutive relationships as well as corresponding parameters of HSHPC were concluded. Material coefficient was got from the experiment and verification was made. In the constitutive relationships, the influence of damage on concrete material characteristic was considered, so they approach to the true characteristic of HSHPC, and is convenient to engineering application.First, the development process of the concrete was reviewed simply;the high performance concrete conception was given;the significance for this research was pointed out;the domestic and overseas related research results were retrospected, and the studied problems were brought forward. Then, the special requests to different components of concrete were discussed, and each component was conscientiously chosen;the forming mechanism was analyzed by microscopic theories. Based on experiment, the main factors that affect the performance of concrete, such as the different material category, different composition ratio, etc. were discussed. So the best raw material combination and the best match ratio were found. Finally, the damage constitutive relationships as well as corresponding parameters of HSHPC were concluded by means of analyzing microscopic action mechanism and using damage theories.The research results will avail the development of composite structures and provide the technique guidance and the theory supports for HSHPC applied to composite structures. It will make more engineers understand and master the action mechanism of concrete material. The results can be applied directly to practical projects and will contribute to establish corresponding structural code.