Feasibility of C&DW Mixed With EAFS and Cement for Sub-Base Applications in India

Rising volumes of construction and demolition waste (C&DW) and electric arc furnace slag (EAFS) have increased the need to reuse them instead of natural aggregates. This paper discusses a laboratory study of cement-treated C&DW–EAFS mixes for pavement sub-base layers. Sixteen mixes of C&DW (100–70%), EAFS (0–30%) and cement (3–6%) were tested for modified Proctor compaction, unconfined compressive strength (UCS) at 7 and 28 days, wetting–drying durability, and repeated-load triaxial tests. Adding EAFS raised the maximum dry density (MDD) and UCS and lowered the optimum moisture content (OMC). EAFS mixes with 4% cement or more reached a 7-day UCS above 1.5 MPa, and those with 20% or more met the wetting–drying weight-loss limit. The resilient modulus (Mr) rose with the bulk stress and was well described by the two-parameter bulk-stress model, which was assessed by the coefficient of determination (R²), the root-mean-square-error-to-observations-standard-deviation ratio (RSR), Nash–Sutcliffe efficiency (NSE) and percentage bias (PBIAS). These mixes can therefore serve as sub-base material under Indian conditions.