Quantitative analysis of the microstructure of interfaces in steel reinforced concrete

This article reports the results of a backscattered electron imaging study of the microstructure of the steel– and aggregate–cement paste interfaces in concrete containing 9 mm ribbed reinforcing bars. The water to cement (w/c) ratio, hydration age, steel orientation, and surface finish were varied. For vertically cast bars, there was more calcium hydroxide (CH) and porosity and less unreacted cement at both the steel– and aggregate–cement paste...