The Research On The Properties Of Recycled Concrete And Recycled Concrete Filled Steel Tube Influenced By Acid Rain And Freeze-Thaw

In order to achieve sustainable development, establish economical society, the recycling utilization of construction garbage has become an urgent problem to resolve, and waste concrete takes a very large proportion in the construction garbage. A little waste concrete was used as roads and the foundation cushion of the building in the past, but most of the waste concrete are shipped to the countryside and the countryside, then optional piled up or buried in the ground, which take ups a lot of land, expends a huge amount of cost on junk transporting, so recycled concrete technology has been an extremely important realistic significance in our country.Recycled concrete is a new type of concrete which make use of the recycled concrete aggregates that waste concrete processed instead of the natural aggregate. Because of the large porosity, high absorption rate and small modulus of elasticity of the recycled concrete aggregates, the general standards for ordinary concrete are not completely suitable for recycled concrete at home and abroad. Many researches about recycled concrete are mainly for the material properties, but a few studies about the structure behavior, especially the durability of the recycled concrete.Durability of concrete structures was affected by acid rain and freezing and thawing seriously in our country. Acid rain influences on the concrete structures in the south of our country greatly, and freeze-thaw problems have affected the construction in the northern China. This paper does some experiment for these respectively, the experiment about recycled concrete under the environment of the simulated acid rain and experiment about the durability of hollow and solid recycled concrete filled steel tube under the freeze-thaw environment.In this paper, the dry-wet cycle method is used to perform on the specimens periodically, and the specimens were divided into two groups—Portland concrete and recycled concrete for contrast in the experiment one. The results show that the performance of the recycled concrete that use recycled concrete aggregate instead of natural aggregates totally is different from the Portland concrete in some aspects after 50 dry-wet cycles; Meanwhile I simulated 20 freeze-thaw cycles which affected on hollow and solid recycled concrete filled steel tube in the laboratory, and then the finite element software—ABAQUS was used to simulate this process. Through comparative analysis, the elastic modulus and the change of strain of hollow and solid recycled concrete filled steel tube under different conditions were obtained. And the confining force between steel and recycled concrete were calculated and analyzed, all of these could be used to pave the way for the future research on analyzing the durability of concrete filled steel tube under the freeze-thaw environment.