Performance and Uniformity of Self-Compacting Concrete (05-0756)**
Mohamed Nagib Abou-Zeid, American University in Cairo, Egypt
Mohamed Samir Roushdy, Al-Kharafi Contracting W.L.L., Kuwait

Self-compacting concrete (SCC) is an emerging concrete type where its cohesive yet flowable consistency help securing proper placement with good homogeneity. Such concrete can be achieved by adjusting mix proportions and incorporating adequate admixtures such as the viscosity modifying (VM) admixtures with no vibration. Yet, the impact of the mix proportions and the role played by the VM as opposed to superplasticizers (SP) admixtures is not fully understood. There also seems to be no unique means for assessment of such concrete and the correlation between various tests needs further work. This study aims at achieving better understanding of the influence of mix proportions on the properties of SCC. Twenty-six mixtures were prepared with various w/c, fine-to coarse aggregate ratio and admixture dosages. Fresh concrete tests including slump flow, L-box, U-box and hardened concrete tests including hardened density, compressive and flexural strength as well as the Rebound Hammer were performed. The uniformity of SCC properties along column specimens was examined. The results reveal that adjusting mix proportions has a major impact on fresh and hardened properties of SCC. The fresh concrete tests were found to correlate well with one another and the SCC strength was comparable to that of reference concrete made with mechanical vibration. Yet, SCC exhibited remarkable uniformity of properties within the components examined. This work suggests that future studies performed on SCC should involve large-sized specimens in which concrete properties are evaluated in various locations.