Comparative analysis of volume change behavior of expansive road subgrades stabilized with waste paper sludge

Expansive soils have a high tendency for volume change in case of fluctuations in moisture content, potentially causing significant damage to light structures, particularly road pavements. This paper investigates the influence of waste paper sludge ([Formula: see text]) as an alternative sustainable stabilizer on the volume change behavior of expansive road subgrade soils of different origins. For this purpose, [Formula: see text] was added to the expansive soils at ratios of 3%, 6%, 9%, 12%, and 15% by dry weight of the soils. A series of Atterberg's limit, swelling, shrinkage, compaction, and consolidation tests were performed on pure soils and soil specimens with [Formula: see text] to attain a comprehensive understanding of the role that [Formula: see text] plays in the volume change behavior of expansive soils. The experimental test results showed that the addition of [Formula: see text] led to a considerable decrease in the plasticity and swell-shrink potentials of subgrade soils. The consolidation settlement of expansive road subgrades was also reduced to some extent with [Formula: see text]. Moreover, the statistical analysis of the test data indicated a significant relationship among different swelling-shrinkage parameters. The experimental results presented here suggest that the [Formula: see text] may be a cost-effective, environmentally friendly, and sustainable stabilizer to reduce the volume change sensitivity of expansive road subgrade soils.