DEVELOPMENT OF SUBBASE MATERIAL FROM ADMIXTURES OF CONSTRUCTION DEMOLITION WASTES AND LATERITIC SOIL

This study explores the potential of using admixtures of construction and demolition waste (CDW) and lateritic soil as alternative materials for subbase construction in road pavement engineering. The research was motivated by the rising cost and environmental concerns associated with traditional subbase materials such as crushed stones and gravels. Materials used were sourced locally, and various laboratory tests—including sieve analysis, Atterberg limits, compaction tests, California Bearing Ratio (CBR), and Unconfined Compressive Strength (UCS)—were conducted to assess their suitability. Admixtures were prepared in varying proportions of CDW and lateritic soil (0% to 100%). Results showed that a 20% CDW admixture significantly improved the CBR and UCS values, meeting international standards for use as subbase materials. Furthermore, the addition of CDW enhanced the particle size distribution and reduced the plasticity index of the lateritic soil, while also improving its workability and dry density. The findings demonstrate that CDW, when properly processed and combined with lateritic soil, can serve as a sustainable and cost-effective alternative for subbase construction, promoting environmental conservation and waste reuse in the construction sector