Studies on chloride fixing in concrete with lead oxide admixture

Day by day the increase in environmental pollution is playing a major role in the corrosion of concrete reinforcement, requiring researchers to focus on its prevention. Among the various corrosives, chloride ions produce major impact by virtue of their small size, high penetrating power, mobility and low activation energy for depassivation. The present research work is aimed at reducing the free chloride content in concrete using lead oxide as an admixture. Different proportions of admixture, varying between 5% and 20% (by weight), with regular increments of 5%, were adopted for concretes with varying curing times (3–28 days). An optimum percentage of chloride reduction was arrived at based on these proportions. The experiments revealed a 13% reduction of free chloride in cement grout and a 35% reduction in concrete with the lead oxide admixture. An increase of 30–60% in compressive strength was also observed for varying curing periods. This admixture, being economical compared with other admixtures such as zirconium oxide and titanium oxide, was found to reduce a higher amount of free chlorides, making it a feasible admixture to adopt. It can be concluded that lead oxide may effectively reduce the free chloride content in concrete, thereby reducing the risk of reinforcement corrosion.