Potential Uses of Sewage Sludge in Highway Construction

Abstract

The sewage treatment plants generate, as by-products, large amounts of sludge containing harmful elements to the environment. This paper investigates the possibility of using 10% of sewage sludge by weight in pavement base layers. The soil stabilization technique was used to improve the residue properties to satisfy the minimum requirements for road bases. The intent of this stabilization technique was to use conventional additives as cement, lime, and emulsion. The main objective was to evaluate the strength behavior of the modified soil. Sludge-soil mixtures with different additive contents (2, 4, 6, and 8%) were prepared for testing. The modified soil samples were subjected to compaction, and then tested for the following parameters: California bearing ratio, unconfined compressive strength, indirect-tensile strength, resilient moduluså, and deterioration tests. Mechanical tests were used to estimate the optimum mix design. Test results indicated that the stabilization of mixtures of soil with sewage sludge has the potential to be used in the pavement industry.