STRENGTH & MICROSTRUCTURE OF CLAY (CL) STABILIZED WITH RECYCLED CONCRETE, WASTE GLASS, AND WASTE STEEL

Abstract

Because of the accumulation of industrial waste products resulting from the growing industrial development, critical environmental issues related to their disposal have arisen. The feasibility of using recycled crushed concrete (RC), waste glass (WG), and waste steel (WS) as stabilizers for clay soil (CL) at the lowest possible cost has been assessed in this research paper. Standard Proctor compaction and unconfined compressive strength (UCS) tests were implemented. Moreover, scanning electron microscopy (SEM) was performed to evaluate the effect of waste-material percentages (5%, 10%, and 15%) on the soil's geotechnical and microstructural behavior. Compaction results showed the maximum dry unit weight increasing by up to 7.3%, 5.0%, and 2.8% for RC, WG, and WS, respectively. Furthermore, adding waste materials resulted in a noticeable increase in the strength of clay soil; this gain scaled gradually with the RC ratio, reaching 94% at 15%. WG improved strength by up to 35.1% at 10%, beyond which no further gain was observed. The highest increase was 132%, recorded at 5% WS, followed by a decline at higher percentages. Accordingly, 15% RC, 10% WG, and 5% WS were identified as the optimum percentages. SEM revealed that RC was associated with a strengthening network that interlaced with the clay; the WG effect was limited to filling voids with little bonding. At the same time, WS improved particle interlocking although it caused localized microcracks. Differences in particle size ranges among the three materials as well as the absence of leaching tests for WS are noted as limitations, with TCLP and XRD analyses recommended for future work.