Use of rice husk ash as a supplementary cementitious material in concrete mix for road pavements

Abstract

The present research analyzes the feasibility of using Rice Husk Ash (RHA) obtained as a residue from an industrial process as Supplementary Cementitious Materials (SCM) in a concrete pavement mix that meets the minimum requirements for a medium traffic level (NT2) road with reference to the General Road Construction Specifications of INVIAS (Colombia). For this purpose, statistical methodologies such as Composite Central Design (CCD), Response Surface Methodology (RSM), and a Multi-Objective Optimization were used to find an efficient mix design that meets the strength and workability criteria using the highest RHA content in partial replacement of cement. The design optimization results show that replacing 24.9% by weight of cement with RHA in a hydraulic concrete mix produces the highest flexural strength (4.2 MPa) of the combinations proposed in the composite central design. This strength could even be applicable for high traffic level (NT3) road, demonstrates that the use of RHA as SCM in concrete mixes for pavements may be feasible.