Effects of sustainable materials on high-performance concrete

The study investigates the physical, mechanical, and durability properties of high-performance concrete (HPC), with particular emphasis on its microstructural characteristics, through the incorporation of sustainable supplementary cementitious materials (SCMs) such as silica fume (SF), ground granulated blast furnace slag (GGBS), and fly ash (FA). A comprehensive experimental program was undertaken involving carefully selected replacement levels of these SCMs in combination with a chemical admixture, aiming to achieve an optimal balance between environmental sustainability and enhanced performance. A total of 486 concrete cubes were cast and tested at different curing ages (7, 28, 56, 90, 180, 270, and 360 days) to evaluate the various properties. Additionally, 54 beams and 54 cylinders were tested to assess flexural and split tensile strengths at 7 and 28 days. Four different mixes, i.e., control, binary, ternary, and quaternary, were developed to study the influence of individuals systematically. The study identified optimum dosages for each SCM based on performance. The results demonstrated that incorporating silica fume noticeably reduces the void content in HPC compared to the control and other combinations. The SF10 binary mix is the best performer overall for strength, durability, microstructure, and sustainability. Microstructural analysis further revealed enhanced interfacial bonding and reduced microcrack formation at the transition zone between the cement paste and aggregates, thereby providing valuable insights into the durability and internal structure of HPC incorporating sustainable binders.