Experimental Studies On Performance Of The Ultra-fine Sand Recycled Concrete

At present, China’s many places are busying with urban renewal, so there are a lof of old buildings were demolished, produce many building garbage, in order to realize utilization of construction waste as resources of building material, this experiment’s raw materials is recycled coarse aggregate which is made of architectural component of demolished brick-concrete structure, at the same time use the HanDan local Ultra-find sand, then using the orthogonal design method researched the workability and the compressive strength of recycled aggregate concrete by experimentation.Firstly, basic performances of HanDan local recycled coarse aggregate were studied in this paper, The results show that the gradation of recycled coarse aggregate can almost meet the requirement to produced concrete, the apparent density and the bulk density of recycled coarse aggregate are smaller than the natural aggregate， water absorp ratio and crushing index of recycled coarse aggregate are bigger than the natural aggregate.Secondly, basic performances of Ultra-fine sand recycled coarse aggregate concrete are studied, the results show that with the recycled coarse aggregate replacement percentage increased, the workability of concrete decreased, and with the sand ratio increased, the workability of concrete also decreased; with the recycled coarse aggregate replacement percentage increased, the compressive strength of concrete decreased too, and with the water-binder ratio increased, the compressive strength of concrete decreased too. From the experiment results we known that With30%of coarse aggregate replacement and10%fly ash replacement and water-binder ratio0.45and10%sand ratio,the slump of Ultra-fine sand recycled coarse aggregate concrete can reach17mm, it’s7d and28d compressive strength were31.9MPa and42.4MPa, Therefore, using certain recycled coarse aggregate replacement and fly ash replacement,recycled concrete still could meet the needs of ordinary concrete on the slump and compressive strength. So it is feasible that preparation Ultra-fine sand recycled coarse aggregate concrete.