Compactive effort influence on properties of quarry dust-black cotton soil mixtures

Abstract

The influence of compactive efforts on properties of quarry dust-black cotton soil mixtures was studied using graphical method, two-way analyses of variance and multiple regression analysis. Addition of quarry dust to the black cotton soil resulted to increases in measured values of maximum dry unit weight (<i>MDUW</i>), optimum moisture content (<i>OMC</i>) as well as California bearing ratio (<i>CBR</i>). The observed increases were more pronounced at the highest compactive effort employed in the study. Measured values of free well strain, swell potential (<i>S_p</i>) and swelling pressure (<i>P_s</i>) decreased as quarry dust content increased; higher values of the parameters being obtained at higher compactive efforts for <i>S_p</i> and <i>P_s</i>. The differences in the measured values of <i>MDUW, OMC, CBR, S_p</i> and <i>P_s</i> resulting from differences in compactive efforts and quarry dust content are statistically significant at 5% level. Partial F-values derived from regression analyses results show that compactive efforts and quarry dust contents significantly influence the measured values of <i>MDUW, OMC CBR, S_p</i> and <i>P_s</i>. It is possible to effectively use quarry dust for construction works involving black cotton soil. However, quarry dust amounts should be such that the mixture does not become non-plastic.