Utilisation of high volumes of limestone quarry wastes in concrete industry (self-compacting concrete case)

In limestone quarries, considerable amounts of limestone powders are being produced as byproducts of stone crushers. High amounts of powders are being collected and utilisation of this by-product is a big problem from the aspects of disposal, environmental pollution and health hazards. In conventional concrete, the introduction of high volumes of limestone quarry dust to concrete mixes is limited due to its negative effects on water demand and strength of concrete. However, these fines can be efficiently utilised as viscosity enhancer particularly in special concrete (like self-compacting concrete-SCC) applications. Thus, the successful utilisation of this quarry dust in SCC could turn this material into a valuable resource. In this paper the usability of a quarry dust limestone powder in self-compacting paste and concrete applications was investigated. In the first part, the physical and mechanical properties of cement pastes incorporating quarry waste limestone powder (QLP) and a powder produced by direct grinding of limestone (PLP) were compared. In the second part, the performance of quarry waste limestone powder in SCC applications were tested and discussed. Results showed that, it is possible to successfully utilise high amounts of quarry waste limestone powder in producing normal-strength SM. Among its observed mechanical advantages, employment of quarry waste limestone powders improved the economical feasibility of SCC production. (C) 2007 Elsevier B.V. All rights reserved.