Utilization of Six Sigma in Quality Improvement of Recycled Aggregates Concrete

The use of recycled demolished concrete in producing new concrete is an established method to improve sustainability through reducing the environmental impact of using virgin aggregates and through reducing construction waste. Six sigma is a set of tools and strategies for process improvement. In this paper, the six sigma DMAIC methodology is utilized to optimize the design parameters in order to improve and assure the quality of the resulting recycled aggregate concrete. The project aims to produce concrete with compressive strength of 25 MPa without using additives. Five parameters were used in the initial analysis that were reduced to three after refinement. The refined parameters are the ratio of recycled coarse aggregates, the ratio of recycled fine aggregates, and the water/cement ratio. It was concluded that the optimum values for the three parameters are 26%, 30%, and 0.5, in order