Sustainable concrete containing recycled aggregates and pozzolana in Sudan

Abstract

Sustainable trails in the building industry called for preserving the natural resources through the production of green concrete. This is concrete where waste materials are used as at least one of its components, or its production does not lead to environmental destruction through the reduction, reuse or recycling techniques. Experimental results from a study on the potential usefulness of recycled coarse aggregates (RCA) blended with locally available natural Pozzolana are outlined in this paper. Eight concrete mix scenarios were considered: a standard mix with 100% natural coarse aggregates (NCA), 25% RCA, 50% RCA, 75%RCA ,100% RCA and no Pozzolana ,100% RCA and 10% Pozzolana, 100% RCA and 20% Pozzolana, 100% RCA and 30% Pozzolana. Slump test was conducted and the results were all within the specific limits. It was conversely realized that the workability decreased in the cases of replacing NCA by RCA with no Pozzolana while an increase was recognized when the Pozzolana was add in the different percentages with the best results achieved with 100% RCA and 20% Pozzolana. The compressive strength results were consistent for the different curing ages with the highest strength being acquired with the mix that contained 100%RCA and 10% Pozzolana. The results of the durability test revealed better values for the wave length speed value when the NCA was replaced by the RCA. Considering these outcomes, the optimum result was achieved in the case of 100%RCA and 10%Pozzolana. Thus, the experimental results offer good indication for a potential usefulness of RCA proposing a reasonable way for preserving virgin natural materials.