Density and Mechanical Strength of Gum Arabic-Sawdust Ash Concrete.

The density and mechanical strengths of concrete are important properties in the study of concrete structures. An experimental study was mounted to study these concrete properties and the effects of using sawdust ash (SDA) and gum Arabic (GA). In studying these effects four concrete mixtures designated as C/00SDA:GA-00, C/00-SDA:GA-0.5, C/10-SDA:GA-0.5, and C/30-SDA:GA-0.5, respectively. The Mix with C/00-SDA:GA-00, is the control (containing zero percent SDA and GA), with a mix proportion of 1: 2.24: 2.71. The cement content was 370 kg/m3 with a water-cement ratio of 0.5. The other mixes contain either 0.5 % GA (only), or 0.5 % GA with 10 % SDA or 30 % SDA replacement by wt. % of cement, as the case may be. The results showed that the addition of GA and SDA to concrete have various degrees of effects on the concrete parameters. The effect of 0.5 % GA decreased the density of the cube sample but increased the beam and the cylinder samples. On the other hand, the mechanical strengths were increased for all the samples. Using GA with SDA reduced the mechanical strengths of all the concrete samples. However, Ca (OH) 2 was reduced by 54 % by the addition of 10 % SDA and 12 % by 30 % SDA addition by wt. % of cement. The empirical models developed on the density and mechanical strengths showed good predictive values with relative predictive errors (RPE) ranging from 0.00% to 0.045 %.