Utilization of Electrolytic Manganese Dioxide (E.M.D.) waste in concrete exposed to salt crystallization

Abstract

In the present study, the physico-mechanical properties and corrosion resistance of reinforced concrete containing Electrolytic Manganese Dioxide (E.M.D.) waste were investigated. Concrete samples prepared in the lab with and without the use of EMD waste were exposed to sulfate and chloride salt solutions. In particular, the test samples were placed in 5% w/w Na2SO4 solution, while chloride penetration resistance was studied in 3.5% w/w NaCl solution. The concrete mixtures were prepared with 0%, 5% and 10% w/w replacement of Ordinary Portland Cement (OPC) with the aforementioned waste additive. For testing, specimens of varying shapes and dimensions were cast; cylindrical reinforced cement mortar specimens were also prepared. Tests for estimating the physico-mechanical properties (compressive strength, modulus of elasticity, porosity and sorptivity), mass loss of steel and thermal response of concrete (DTA/TG) were performed; the carbonation depth of mortars exposed to atmospheric conditions was also estimated. The experimental results generally suggest that the EMD waste additive does not affect negatively the properties of concrete partially immersed in chloride salt solution; in addition, the anticorrosive effect of EMD waste on steel rebars embedded in cement mortars was also observed. On the other hand, the composite concretes immersed in sulfate salt solution exhibited inferior values for all measured properties.