Study On Modification Of Recycled Concrete Aggregate And Its Application

Since 21th Century,China has seen the vigorous development of construction industry,and construction waste greatly endangered the natural environment,because these waste was not treated in an appropriate way.On the other hand,the exploitation of natural resources produced a lot of building materials,posing a major threat to the ecological environment and natural resources.The increase of construction waste recycling,processing and reuse,not only can solve waste and the damage to the natural environment,but can alleviate the ecological and energy because of sand mining,will waste concrete for effective and reasonable use has extremely important to solve these problems.The basic properties of recycled aggregate,modification,mechanical properties of recycled aggregate concrete,application are studied.Compared with natural aggregate concrete,recycled coarse aggregate has low density,high porosity,high water absorption,high moisture content,high crushing index value,poor stability and high mud content.The density,water absorption rate,and crushing index of five kinds of different quality coarse aggregate were tested;the results show that the modified method of recycled aggregate can make the basic properties of recycled aggregate is improved;the apparent density,bulk density and crushing index of recycled aggregate were increased after water glass solution,PVA solution and silane emulsion treatment,and the water absorption rate decreased obviously.The mechanical properties of concrete made of five kinds of coarse aggregate are determined by experiments;Cubic compressive strength,axial compressive strength and splitting tensile strength of recycled coarse aggregate recycled concrete is significantly less than natural concrete at the same age,the mechanical property loss of recycled concrete is improved by the modification of recycled aggregate,The mechanical properties of recycled concrete modified by PVA solution were the best,followed by water glass solution,silane emulsion modified recycled aggregate of recycled concrete early strength is better than the other two methods.Finally,the application of recycled coarse aggregate in road engineering is studied;in our country,recycled concrete is used in subgrade and pavement parts of some roads,as test sections,the effect is good.RSLF made from recycled aggregate is applied to the road base,the effect is nice;recycled concrete for lack of existing research on road surface layer,need further exploration.