Engineering Properties of Copper Slag–Fly Ash–Dolime Mix and Its Utilization in the Base Course of Flexible Pavements

Abstract

The main objective of the present study is to quantify the influence of important factors such as fly ash content, dolime content, and curing period on the shear strength and stiffness characteristics of copper slag–fly ash–dolime (CFD) mix for its effective utilization in the base course of flexible pavements. Unconfined compression tests are conducted on specimens with different fly ash (10–40%) and dolime (0–20%) contents cured up to 28 days. A mix of 20% fly ash and 80% copper slag stabilized with 15% dolime was found to be the optimum for use in the base course of flexible pavements. Next, durability tests and unconsolidated undrained triaxial tests are performed on the optimum mix. The strength achieved after 28 days of curing period for the optimum mix was found to be least susceptible to the effect of alternate wet and dry cycles. Empirical relationships are developed to estimate important design parameters such as deviator stress at failure, elastic modulus, and cohesion of the stabilized mix, which can be used to determine dolime and fly ash contents to achieve a target strength within a given curing period. Finite-element analyses of a five-layer flexible pavement system are carried out; and the equivalent thickness, service life ratio, and cost-effectiveness of CFD mix in relation to the conventional water-bound macadam (WBM) layer are evaluated.