Study on the Interfacial Transition Zones of Recycled Aggregate Concrete

Background/Objectives: The objective of the present paper is to study the effect of admixtures and the mixing approach on the Interfacial Transition Zone (ITZ) of Recycled Aggregate Concrete (RAC). Methods/Statistical analysis: The micro structure of RAC is generally analyzed by the Vickers micro-hardness test, Atomic-Force Microscopy (AFM), Nanoindentation and scanning electron microscope (SEM). The various mixing approaches were presented for partially and fully replacement of recycled aggregate (RA) which basically enhanced the properties of RA. It is also observed that the use of fly ash and silica fume improve the properties of ITZ. Findings: This paper presents a review of the studies on the micro structure and mixing approach of RAC elements and Structures. The behavior of RAC has been studied since last 45 years. In this paper micro structure of RAC and mixing approaches conducted by many researchers are critically studied for the enhancement of strength and durability of RAC. The findings and recommendations derived from the earlier research may be helpful for the design engineers and professionals for proper design of structural components using RAC. This will also help in popularizing the use of recycled concrete aggregate in Civil Engineering field. Applications/Improvements: To achieve sustainable issue in construction area the use of waste concrete as RAC is an important focus for construction industries and for the safe guard of the natural environment.