DEVELOPMENT OF SUSTAINABLE SELF-CONSOLIDATING HIGH PERFORMANCE CONCRETE INCORPORATING CEMENT KILN DUST

Abstract

Sustainability is the cornerstone of the cement industry, not only in the products that use cement, but also in its manufacturing process. Cement manufacturing is a critically important industry throughout the world. The current production of cement worldwide accounted for about 2.5 billion metric tons (Wayne & Donald, 2008). Cement kiln dust (CKD) is a by-product material of the cement manufacturing process. Enormous quantities of CKD were produced from cement industries and estimated to be 3–4% of the total produced cement (Najim, Mahmod, & Atea, 2014). Majority of these were disposed to landfills while very little were recycled to the kiln. The disposal of this material into landfill is not only detrimental to the environmental issues but also decline substantial amount of production profit to the cement industries. Moreover, due to the dwindling of space for landfill and growing restrictions on environment, landfill cost might be high. Self-consolidating high performance concrete (SCHPC) is an advanced class of concrete that can flow through congested reinforcement or intricate geometric configurations under its own weight without any compaction activity and it does not segregate. Research and development in the use of supplementary cementing materials (SCM) to produce SCHPC have continued to gain attention worldwide. This is as a result of the global quest to reduce carbon dioxide emission to the threshold that will be tolerated by the earth. Despite the successes achieved by replacing cement with supplementary cementing materials (SCM), a number of drawbacks were unavoidable. This research work, focuses on the impact of CKD on the fresh and hardened properties of SCHPC. Assessment of the physical and chemical characteristics of the CKD were performed to ascertain the feasibility of using it as a cement replacement. Furthermore, a simple mix of 0.35 w/c ratio was design and properties of fresh and hardened SCHPC were determined and evaluated. Various SCHPC are produced at a replacement level of 15%, 30% and 45% of CKD content by weight of ordinary Portland cement (OPC) were used. The fresh SCHPCs were tested for filling ability, passing ability and segregation resistance. The hardened SCHPCs were tested for compressive strength. The result of the workability showed that the flow ability, passing ability and segregation resistance are retarding with increased in CKD but all are within the specified range of EFNARC (2002). The compressive strength of SCHPC containing CKD are generally lower than that of the control specimen, However, all the results for 28 days except for 45% replacement of OPC were above 40 MPa specified for high strength. Nevertheless, the addition of CKD at 15% improved the compressive strength of SCHPC