Rheological and Mechanical Behavior of Self-Compacting Concrete with Mineral Admixtures

The fresh, mechanical, bond, and acid resistance performances of concrete containing Flyash and Palm Oil Fuel Ash (POFA) are studied here as partial cement replacement materials. Ten mix proportions prepared by varying combined replacement levels from 10% to 50%. The results showed that all the blended mixes achieved better workability than conventional concrete, as evidenced from the slump values in the range of 705–729 mm with improved filling and passing ability. Mechanical strength at 7, 14, and 28 days of age demonstrated that the compressive strengths obtained for moderate replacement levels, 10–30% SCM blends, were higher than control, while Trial 4 presented the highest compressive strength of 27.52 MPa at 28 days. The results of the bond behaviour through pull-out tests indicated an improved steel–concrete interaction in SCM mixes, where Trial 7 reported the maximum bond strength of 7.72 MPa. The durability performance, depicted through hydrochloric acid exposure, revealed a reduction in weight loss for all blended mixes, and the minimum deterioration of 8.16% was recorded for Trial 7. Overall, this study demonstrates that the combined use of Flyash and POFA significantly enhances workability, strength development, bond characteristics, and acid resistance and sustainable supplementary cementitious materials.