Fresh, mechanical and microstructural behaviour of high-strength self-compacting concrete using supplementary cementitious materials

Sustainable practices in the construction sector have become a major issue due to the overuse of natural raw materials. Industrial by-products like fly ash (FA), silica fume (SF), and marble powder (MP) incorporation in concrete production will be assessed in this paper in terms of fresh, mechanical, and microstructural states. Consequently, this study proposes an in-depth investigation of SCMs applied with varied substitute cement amounts, looking at components like MP, SF, and FA. The impacts on fresh characteristics of HSSCC were assessed using slump flow, V-funnel time, T50 time, L-box ratio, and J-ring slump flow. Compressive, flexural, and splitting tensile strength tests were performed to analyze the mechanical properties. Energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscope (SEM) techniques were used for the microstructural examination of HSSCC. It has been found that SCMs, including MP, FA, and SF, may enhance the characteristics of concrete. The slump flow values, which indicate the flowability and filling ability of HSSCC, were improved by a maximum of 9.6% for 20% SF and 10% for both FA and MP replacement. The most promising outcomes on the basis of mechanical operation were gained by using SF, MP, and FA in HSSCC at respective percentages of 20%, 10%, and 10%. This mixture revealed an increase in compressive strength of a maximum of 15% at 56 days compared to the control mixture, which contained 10% MP. However, the excessive addition of MP negatively impacted the strength of the concrete. The EDS examination illustrated that the ‘Ca’ to ‘Si’ proportion in HSSCC significantly affects the emergence of strength. This study will enlighten users during the preparation of high-strength self-compacting concrete (HSSCC) by replacing ordinary Portland cement (OPC) with different available supplementary cementitious material (SCM) combinations.