Response of self-consolidating cement paste systems containing Acacia Nilotica Gum as an organic admixture

Abstract

This research characterizes the gum obtained as a natural organic ooze-out from Acacia Nilotica trees, indigenously known as “Keekar”, through Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared Spectroscopy (FTIR) experimental techniques. It reports the response of self-consolidating paste systems (SCPs) containing Acacia Nilotica Gum (AG) in powdered form in ratios of 0.33%, 0.66% and 1% by weight of cement. The results are of interest to construction and civil engineering professionals and showed that AG enhanced the viscosity of SCPs which in turn improves their stability. Also, AG addition increased the water demand, setting times and early age expansion of SCPs while the heat of hydration, density and compressive strength got reduced. Reduction in density is attributed to incorporation of air voids and this may be exploited in energy efficient infills of buildings and possible improved freeze-thaw resistance. Most of the lost compressive strength due to AG incorporation was regained with the addition of Secondary Raw Materials (SRMs) including fly ash (FA) and limestone powder (LSP).