Effectiveness of cement kiln dustsilicate based mixtures on plasticity and compaction performance of an expansive soil

In an attempt to seek for cost-effective construction materials which is expected to stimulate sustainable road pavements, the use of waste industrial materials such as cement kiln dust (CKD) has become necessary. Metakaolin (MK) is a good silica-based pozzolanic material derived from calcined kaolin. The study entails understudying the effectiveness of these materials on plasticity and compaction response of an expansive soil. Laboratory examinations were initiated on both virgin and treated soils. The blending was achieved with the mixtures of 0 -8% CKD and 0 to 10% MK, respectively. In the course of this study, the addition of additives into the virgin soil facilitated some alterations in the soil matrix. The consistency examinations of soil materials displayed a diminishing trend with the introduction of CKD-MK mixtures into the soil matrix which facilitated a considerable level of improvement in the plasticity tendency of the soil. For the compaction response, the increment in CKD and MK proportions occasioned the enhancement of maximum dry density (MDD) and a corresponding diminishment in optimum moisture content (OMC). The scan electron microscopy (SEM) of the virgin soil displayed series of cracks whereas the soil-CKD-MK mixtures did not show same which could be facilitated by the crystalline formation on adding the additives. The analysis of variance was employed for the testing of significant level of additives on the tested property. Thus, an optimal blend of 8% CKD/8% MK showed a drastic effect on the plasticity and compaction properties. It can be inferred that 8% CKD/8% MK blend in the soil could be useful as alternative to the conventional stabilizing materials.