Strength and Corrosion Resistance of Superplasticized Concretes

This paper reports results of an investigation evaluating the strength development and long-term corrosion resistance of concrete mixes incorporating a superplasticizer, two fly ashes, and a natural pozzolan. The compressive strength was determined up to 90 days. Reinforced concrete specimens were immersed in sodium chloride solution for more than five years. The corrosion rate of reinforcing steel was monitored using electrochemical techniques. Results indicate that the compressive strength of concretes incorporating both a superplasticizer and pozzolans is lower than that of plain superplasticized concrete up to 90 days. However, there is marked improvement in the long-term corrosion resistance of these concretes over plain concrete. This indicates that where durability of concrete (against chloride ingress) is the primary criterion, pozzolans and chloride-free superplasticizers can be used as admixtures to produce impermeable and corrosion-resistant concrete.