Use of Sludge Ash as a Stabilizing Additive in Soil-Cement Mixtures for Use in Road Pavements

This paper presents a study evaluating the use of sludge ash as a stabilizing additive to soil-cement mixtures for use in base and subbase road pavements by investigating the mechanical behavior of these mixtures. The methodology consisted of materials testing, including the geotechnical characterization of the soil and the mechanics of the soil-cement and the soil-cement-sludge ash mixtures. An unconfined compression test evaluated the mechanical behavior of soil-cement mixtures with cement contents of 3, 6, and 9% compressed with normal, intermediate, and modified pressures. The sludge ash contents added were of 5, 10, 20, and 30%. The results indicate increasing strength for all ash levels studied. The largest gain in strength was for a mixture with 20% sludge ash, which increased the strength by 26% compared with the mixture without sludge ash.