Assessing the corrosion performance for concrete mixtures made of blended cements

Although it has been used worldwide for decades, manufacturing of Blast Furnace Slag Cement (CEM III/A) has boomed since it was specified in the Egyptian Cement Standard ESS 4756 on 2006. However, corrosion protection efficiency of the Egyptian (CEM III/A) cement has rarely investigated. Therefore, in this research work corrosion performance was investigated for different concrete mixtures made of Egyptian manufactured (CEM III/A 42.5N), (CEM III/A 42.5N) partially replaced with fly ash and Ordinary Portland cement (CEM I). A total of 432 reinforced concrete (i.e. lollipop) specimens were exposed to impressed current accelerated corrosion technique. In addition to the cement types, the corrosion influence of the concrete mixture water/binder (w/b) ratio and cement content were assessed as well as the impact of reinforcement cover and exposure duration on reinforced concrete specimen's corrosion performance. The corrosion protection was assessed by the corrosion current and it was quantified by measuring the rebar diameter loss. The chloride ion penetrability, water permeability and measured corrosion current were significantly reduced by replacing (CEM I) with either (CEM III/A) or (CEM III/A + FA) cements specially for large reinforced concrete cover having optimum cement content and minimum w/b ratio with suitable workability.