Performance analysis of self compacting concrete by incorporating fly ash, coal gangue powder, cement kiln dust and recycled concrete powder by absolute volume method

To achieve environmental sustainability and improve material characteristics, this study examines the performance of self-compacting concrete (SCC) that incorporates different industrial by-products, including fly ash (FA), coal gangue powder (CGP), cement kiln dust (CKD), and recycled concrete powder (RCP). Through an experimental program, the research evaluates the fresh and hardened properties of SCC as well as its microstructural features. Slump flow, T50, and V-funnel tests were utilized to evaluate the fresh characteristics, while the compressive strength was the main emphasis of the hardened property at 7, 14, and 28 days of curing periods. To clarify the internal structure of the material and the pozzolanic processes taking place therein, further microstructural investigations were carried out using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. Due to pozzolanic reactions and the densification of the microstructure, the results show that adding these industrial by-products not only makes SCC more workable but also gradually increases its compressive strength. In particular, the study shows that combinations with FA, CKD, and RCP perform better than CGP in terms of flowability and strength development. The results highlight the technical advantages of improving concrete qualities through material innovation, in addition to the possible environmental benefits of recycling waste materials in construction.