Cement kiln dust and fly ash blends as an alternative binder for the stabilization of demolition aggregates

Cement kiln dust (CKD) is an industrial by-product formed during the manufacture of cement. Fly Ash (FA) is the by-product of coal-fired electricity generation. Construction and Demolition (C&D) materials are alternative aggregates used in construction applications. CKD is calcium-rich whereas FA is silica-rich, hence the unique combination of these two pozzolanic materials (CKD + FA) were investigated as an alternative binder to stabilize C&D materials. The usage of CKD + FA to stabilize C&D aggregates comprised of Recycled Concrete Aggregate (RCA), Crushed Brick (CB) and Reclaimed Asphalt Pavement (RAP) will have environmental and economic benefits. The strength characterization of CKD + FA stabilized C&D materials was evaluated by undertaking Unconfined Compressive Strength (UCS) tests. The durability of the CKD + FA stabilized C&D materials under simulated loadings was evaluated by Repeated Load Triaxial (RLT) tests to determine the resilient modulus (MR). The optimum performance for stabilizing C&D materials was obtained at the mix design with 20%CKD + 10%FA.