Effect of mix design parameters on the behavior of compression cast concrete

Abstract

Compression casting is a novel method for producing high-performance concrete. However, the optimal mix design parameters for normal concrete (NC) may not be suitable for compression cast concrete (CCC) due to the high compression pressure involved during casting. This study addresses the lack of research on CCC mix design and examines the influence of different parameters, including aggregate gradations, maximum particle size, sand ratios, and water-to-cement (w/c) ratios, on the performance of NC and CCC. Fourteen groups of concrete samples were prepared with varying aggregate grading, particle sizes, sand content, and w/c ratios. The density, compressive strength, elastic modulus, peak strain, and stress-strain behavior were analyzed. CCC specimens exhibited superior stress-strain relationships compared to NC specimens. CCC can be produced with different aggregate gradings and particle sizes. Notably, CCC specimens with a maximum aggregate size of 25 mm and no particles between sizes 5 mm and 9.5 mm (grading - 4) demonstrated the highest compressive strength and elastic modulus. CCC specimens with a sand ratio of 38% outperformed those with ratios of 28% and 48%. Increasing the w/c ratio showed similar stress-strain behavior for both NC and CCC specimens. This study proposes relationships between the properties of NC and CCC based on the findings. The results provide valuable theoretical and experimental insights for engineering applications involving CCC, considering different aggregate grading, particle size, sand ratio, and w/c ratio combinations.