Properties of self-compacting concretes prepared with recycled aggregate

The recycling of construction and demolishing wastes as Recycled Concrete Aggregate (RCA) is an important issue for major urban cities since it provides an alternative mean to the dependence of construction industry on natural aggregates. The use of RCA in Self Compacting Concrete (SCC) is a relatively new research area on which a very limited scientific research has been carried out in the current literature. The drawbacks in widespread commercial use of RCA in SCC are mainly caused by the weak and porous old cement mortar adhered on RCA. In practice, this adverse effect and some hitherto unknown properties of SCC with treated and untreated RCAs prevent the maximum utilisation of RCA in SCC. This thesis aims to overcome this short-coming in the current literature by assessing the properties of SCC using treated and untreated RCAs. Moreover, in this thesis, the potential treatment methods and some important rheological, mechanical and durability properties of SCC with RCA have been investigated. The response surface method was employed in the multi-objective optimization analysis along with the analysis of variance to obtain the best possible resolution of RCA in SCC. The results reveal that the applied RCA treatments of two stage mixing approach and water glass provide better microstructures leading to significant strength improvements of SCC. In addition, Herschel-Bulkley and modified Bingham models provide well defined rheological representations for SCC with RCA.