Experimental Study On The Shrinkage Properties Of Recycled Aggregate Concrete

Human urbanization accelerated the development of construction industry,long time of high investment,high pollution and low efficiency of traditional construction industry pattern,brings the natural environment and ecological balance.Therefore,to strengthen the social and economic growth and environmental protection of mankind,walk the road of sustainable development is a worldwide topic.This test is to made of recycled coarse aggregate and fine aggregate all recycled concrete as a building material,adapter strength grade for C30,C40 and C50 completely recycled concrete,the C40 for control group is divided into aggregate prewetting and aggregate prewetting,a total of four groups,block,the recycled concrete autogenous shrinkage and drying shrinkage test research,the period of one year,analysis the authigenic shrinkage and drying shrinkage characteristics of recycled concrete,and the prediction formula was put forward,for the actual construction of recycled concrete offers scientific research base.This research project is based on the existing mature production technology and equipment,concrete with recycled coarse aggregate and fine aggregate replace the mixture of the recycled concrete,which decrease the equipment cost,and make full use of the recycled aggregates,is a new type of green environmental protection and ecological characteristics of building materials.This experiment through research analysis can get the following conclusion:(1)Spontaneous contraction increases with the reduction of water cement ratio,dosage of gelled material,the more spontaneous contraction deformation faster.Recycled concrete aggregate on the spontaneous contraction,this is because the recycled coarse and fine aggregate concrete matrix in the process of the broken by the slight damage,at the time of separation,surface water slurry package,therefore,the general regularity of recycled concrete autogenous shrinkage is presented.(2)The drying shrinkage with the improvement of the recycled concrete strength grade,the drying shrinkage value is becoming more and more smaller.The recycled concrete not prewetting of drying shrinkage value than early shrinkage value increased obviously after prewetting,late drying shrinkage value basically remain unchanged.(3)Through since the birth of the recycled concrete shrinkage and drying shrinkage of the analysis and research,it is concluded that the recycled concrete autogenous shrinkage and drying shrinkage calculation formula,for later study provides theory basis for the shrinkage of the recycled concrete performance.