Title: Effect of Natrojarosite as Replacement to Portland Cement in Roller-Compacted Concrete Pavement Mixtures
Author(s): Solomon Debbarma and G. D. Ransinchung R. N.
Publication: Materials Journal
Appears on pages(s): 91-100
Keywords: filler effect; natrojarosite; roller-compacted concrete pavement; zinc waste
The paper aims to address the use of natrojarosite, an industrial waste material, as a partial replacement to portland cement in roller-compacted concrete pavement (RCCP) mixtures. Natrojarosite particles were used in proportions of 0%, 5%, 15%, 20%, and 25%, by weight of cement, respectively. It was observed that the optimum moisture content increases as the natrojarosite replacement level increases but were still lower than that of the control mixture. Meanwhile, the maximum dry density was found to be enhanced until 15% of natrojarosite replacement level, and subsequently, the strength and transport properties were also found to be improved. Scanning electron microscope images confirmed that the natrojarosite particles acted as a filler material which improved the transition zone and pore structure of the hydrated matrix. Contrarily, higher replacement levels showed reduction in the concrete strength and higher susceptibility to acid attack primarily due to the high sulfur trioxide content in the natrojarosite particles. Nevertheless, natrojarosite of up to 15% could be used to improve the strength and durability of RCCP. Moreover, the use of natrojarosite particles would lower the consumption of portland cement and eliminate the disposal issue of the harmful natrojarosite waste.