Research On Design Method Of The Mix Proportion For Recycled Cement Concrete Based On Additional Water

As a premise for ensuring the quality of the project,adequate and reasonable use of recycled aggregate resource has a positive solution for solving the wasting concrete piling and the environment pollution or damage during transporting.Because of the particularity of recycled aggregate,the mix proportion design method of recycled cement concrete should be distinct with normal cement concrete.In the context,this thesis puts forward the mix proportion design method for single-doped recycled aggregate concrete and optimizes the design scheme of double-doped recycled aggregate mix proportion based on experiment with orthogonal experiment.First of all,the basic characteristics of recycled aggregate such as composition traits,grading and crushing index were experimented and analysed by comparing with corresponding indexes of natural aggregate.Secondly,aiming at the shortage of existing determination method for water absorption of aggregate when used for recycled coarse aggregate,the union wax-sealed determination method for recycled coarse aggregate and the corresponding computing formula of apparent density were put forward.and the water absorption of recycled coarse aggregate with different particle sizes was measured.The computing method and formula of additional water was put forward according to the mix proportion of recycled concrete.Considering the additional water of recyled concrete,the mix proportion and the experiments of workability and strength of recyled concrete were completed.The strength affection equation of recycled concrete on the basis of recycled aggregate replacement percentage was fitted out according to the experiments results.The design method of single-doped recycled aggregate concrete mix proportion was put forward by correcting the water usage and strength formula on the basis of design method of normal concrete mix proportion.The feasible replacement rate of recycled coarse aggregate or recycled fine aggregate were put forward according to the influence on recycled concrete workability and strength of single-doping recycled coarse aggregate or recycled fine aggregate.The workability and strength of recycled concrete simultaneously doped with recycled coarse aggregate and recycled fine aggregate were experimented and researched by orthogonal experiment,and the optimization scheme of mix proportion for double-doped recycled aggregate concrete was put forward.