A Long-Term Influence of Sewage Sludge Ash as an Additive on Shearing Capacity in Collapsible Soil

The growing concerns about the negative environmental impact of sewage sludge and its disposal have drawn attention. However, the volume of sewage sludge is increasing significantly. Therefore, it is important to establish an effective cycle for the application and utilization of this material in order to mitigate its bio-environmental risks. Given the extensive presence of collapsible soil, the rapid urbanization, and the expansion of large cities on such soil, it is crucial to investigate the stability and improvement of this type of soil. This research project aims to evaluate the long-term effects of sewage sludge ash on the shear strength of collapsible soil. The use of sewage sludge ash as an additive is being considered. Through initial assessments, the shear strength of the soil under investigation is determined both without the additive and with varying weight percentages of 2%, 4% and 6%. The tests are conducted on samples remoulded over a period of 30 days. The final results indicate that increasing the percentage of sewage sludge ash as an additive enhances soil cohesion while reducing the internal friction angle ɸ. Furthermore, a comparison is made between samples remoulded 3 days and 30 days, revealing a similar behavior in terms of shearing capacity for both time durations.