Soil stabilization with water treatment plant sludge for road paving

Abstract

One of the methods to minimize the negative impact caused by inadequate disposal of Water Treatment Plant Sludge (WTPS) is to mix it with the soil, applying the material in engineering works. In this research, the objective was the use of WTPS for soil stabilization purposes, verifying the improvement of the characteristics and properties with 0%, 15%, 30% and 50% of sludge, for application in the base and sub-base layers of road pavements. Characterization, compaction, permeability, Resistance to Simple Compression (RCS), and California Bearing Ratio (CBR) tests were carried out. However, none of the mixes met all the necessary requirements for use in the pavement layers, but it is concluded that there was an increase in the RCS, CBR and impermeability of the mixtures compared to the reference mixture (100% soil). The RCS increased 142.75% of the soil for a blend with 30% sludge, CBR increased 76.52% of the soil for mixture with 50% WTPS, and the permeability of blends with 15%, 30% and 50% sludge was lower than then with only the soil. These results show that these mixtures can be useful for other types of applications in Geotechnics, being able to contribute to the sustainable destination of WTPS.

Keywords:
soil stabilization; water treatment plant sludge; road pavement; sustainability