Effect of supplementary cementing materials on concrete resistance against carbonation and chloride ingress

摘要

In this work the durability of Portland cement systemsincorporating supplementary cementing materials (SCM: silica fume, low-andhigh-calcium fly ash) is investigated. Experimental tests simulating the maindeterioration mechanisms in reinforced concrete (carbonation and chloridepenetration) were carried out. It was found that for all SCM tested, thecarbonation depth decreases as aggregate replacement by SCM increases, andincreases as cement replacement by SCM increases. The specimens incorporatingan SCM, whether it substitutes aggregate or cement, when exposed to chloridesexhibit significantly lower total chloride content for all depths from the surface,apart from a thin layer near the external surface. New parameter values wereestimated and existing mathematical models were modified to describe thecarbonation propagation and the chloride penetration in concrete incorporatingSCM.