Solid Waste Material Reuse Analysis: Filling the Road Subgrade with Riverway Silt and Sediment

Abstract

This study proposes to explore solid waste material (SWM) reuse with the riverway silt and sediment, and examines the impacts of chemical composition on the road construction through sensitivity analysis. Considering the characteristics of silt mixture, it is necessary to investigate the modified materials to improve the mechanical feasibility for subgrade filling. In this study, modification schemes for construction waste and garbage slag presented well mechanical properties and environmental benefits in sensitivity analysis, especially for the high-water content silt modified by the garbage slag and lime mixture. The results indicate the lime-improved silt with medium water content is a cheap and high-performance material compared to the original silt. Moreover, modified silt demonstrated superior features in particle size, permeability and bearing capacity. Among six lime-improving schemes, the California bearer ratio (CBR2.5) increased from 7.1 to 19.6, while the minimum CBR2.5 was 2.45 times to the original silt. At last, this study proposes the engineering measures to improve the silt mixture subgrade to prevent heavy metals from polluting the water and soil environment. Further implications were also discussed.