Mechanical performance and fracture behaviour of roller compacted concrete with organo-mineral additives

Abstract

In recent years, Roller Compacted Concrete (RCC) has gained increasing attention in pavement construction due to its economic advantages, rapid placement, and the ability to utilize locally available materials. Despite the long history of RCC application worldwide, its use in Ukraine remains limited, which highlights the need for further research and adaptation of this technology to local conditions. An important direction of modern studies is the development of RCC mix designs incorporating partial cement replacement with active mineral additives and the use of a complex plasticizing admixture. This approach aligns with current trends aimed at reducing cement consumption, lowering energy demand, and decreasing CO₂ emissions, thereby contributing to more sustainable and environmentally responsible construction practices. This paper presents the results of experimental investigations of the mechanical properties and microstructure of RCC produced using locally sourced materials. The research methodology included optimizing the mix composition, determining workability parameters, and conducting comprehensive tests on hardened concrete specimens. The results demonstrated that the combined action of the chemical admixture and fly ash promotes densification of the cement matrix, activates hydration processes, and leads to the formation of additional hydration products, resulting in a more uniform and dense microstructure. The optimized RCC mix modified with a superplasticizer and fly ash exhibits a significant increase in compressive and flexural strengths compared to the reference composition. The findings confirm the effectiveness of organo-mineral additives in improving the mechanical performance and durability of RCC, supporting the feasibility of broader implementation of this technology in Ukrainian pavement and industrial construction.