Waste crushed rock stabilised lateritic soil and spent carbide blends as a road base material

Waste crushed rock (WCR) and spent carbide (SC) composite were used to stabilise lateritic soil (LS) as a road base material. Laboratory investigations were conducted on LS blended with up to 80% WCR by weight of the dry soil to determine the ideal grading and Atterberg limits, which satisfy the Ghana Ministry of Transport (MoT) specification. 40% WCR content was noted as the ideal content. The 40% WCR was then treated with up to 10% SC by weight and subjected to geotechnical tests. The findings revealed notable improvements in the properties of the WCR/LS blend with increasing SC content. The improvement in terms of strength was assessed using California bearing ratio (CBR), which showed ascending values with SC contents. The addition of SC also increased the fines content. Despite the improvement in geotechnical properties of the stabilised LS, comparison with the Ghana MoT standards for road base material indicates that only 10% SC content met the minimum swell specification. However, the grading curves for 0%-7% SC contents substantially fell within the grading envelope. Similarly, all the CBR values passed the minimum specification. Based on the CBR and grading specifications, 40% WCR with 7% SC content is recommended for road base construction.