Transforming Construction and Demolition Waste into Soft-Soil Treatment for Paving Design

Abstract

AbstractConstruction and demolition wastes (CDW) are a concern in urban areas, in addition, it is well understood that soft soils are inappropriate for paving designs. Therefore, this paper presents an alternative solution combining CDW and a soft silty soil, aiming to overcome the soft soil drawbacks by repeated loadings. For this purpose, a laboratory study was developed, comprising both resilient modulus (MR) and unconfined compressive strength (UCS) tests over soil and soil-CDW compacted blends, to evaluate the mechanical properties of the proposed stabilization. Also, three compaction efforts (standard, intermediate, and modified) and a curing time of up to 90 days were used. The UCS of blends was also measured with the identical specimens with which the resilience tests were carried out. The results indicated that incorporating CDW (size sand and gravel materials) into the soil improves the qu and MR for all compaction energies, and the Resilient Modulus test affects the UCS of all blends, increasing its effect with the decrease in compaction effort. Repeated loads caused a decrease in the specimen's voids whereby the density increased and, therefore, qu. Finally, the results conclude that the compacted mixtures in the intermediate effort and 40–60% CDW by weight are potentially applicable in pavements compared to the traditional soil–cement base/subbase.