Experimental study on bonding properties of recycled concrete

Abstract:

To promote the use of recycled concrete in practical engineering,pull-out tests were carried out to study the influence of Coarse/Fine Recycled Concrete Aggregate(CRCA/FRCA) replacement rate,water-cement ratio and the anchoring conditions on the compressive strength and bonding properties of Recycled Aggregate Concrete(RAC).The results show that: the bond strength of RAC rises with the increasing of CRCA replacement rate,and arrives at the maximum when the rate= 60%,then reduces;the bond strength of RAC reduces while the FRCA replacement rate increases,and it is better than that of ordinary concrete;too much CRCA/FRCA replacement will reduce the compressive strength of RAC;lower water-cement ratio can improve the compressive strength and bond strength of RAC,and water-cement ratio variation has less influence on RAC than that of ordinary concrete;appropriate increase in the thickness of concrete cover(≤3 d) and the anchorage length can increase the bond strength of RAC.In addition,by concerning the relationship between the bond strength of RAC and CRCA/FRCA replacement rate,water-cement ratio,compressive strength,anchorage length,a formula was established.