Experimental Study On Mechanical Properties Of Concrete With Recycled Aggregates And Admixtures

This research is a vital sub-item of"analysis on mechanical properties and microstructure of recycled concrete"which is funded by Natural Science Foundation of Heilongjiang province.With the development of construction industry, wastes of construction have been growing day by day, and most of them are waste concrete. Besids the charge for the jillion wastes disposal is very high, it also causes a lot of environmental problems. In addition, the large demand of concrete requests the exploritation of natural resoures--sand and stone, and so the natural resource has been on the exhausted edge for unceasing exploration. Then based on the thought of environmental protection and sustainable development, the technology of recycled concrete can solve this problem efficiently.This paper summarizes that recycled concrete brings the influence to the environment, its domestic and international research status. This paper mainly studies mechanical properties of recycled concrete with different recycled aggregates and admixtures referring to the result of recycled concrete.Through analysis of the method that is currently used on how to gain recycled concrete aggregate and then after drawing lessons on processing manner of waste concrete from abroad, jaw crusher is used to produce recycled aggregate. Various physical and mechanical properties of recycled aggregate are investigated according to Standard and Test Method for the Fine and Coarse Aggregate of Normal Concrete (JGJ52-2006). Test results indicat that the recycled aggregate has the reputation of low density, high water absorption and porosity, low strength with those of natural aggregates.Compressive strength and splitting tensile strength results of recycled concrete are investigated systemically through experimental work with 120 cubes, mainly covers the effect of recycled aggregate type, fly ash replacement ratio, slag replacement ratio and fly ash-slag replacement ratio. At the same time, the relation between the compressive strength and the splitting tensile strength of recycled concrete is obtained by regression analysis. 57 complete stress-strain curves of recycled concrete prism are obtained through the mechanic property test employing MTS multifunction test equipment, together with its automatic collector. Based on the results, regularitys of peak stress, peak strain, transverse deformation and elastic module are obtained. And also the equation of complete stress-strain curve for recycled concrete is established for the first time.This paper offers some references for further research on properties of recycled concrete structure.