Optimizing strength behavior of sustainable ultra high performance green concrete with minimum cement content using response surface method

The main objective of this article is to utilize the response surface method (RSM) for optimizing and predicting the compressive strength, flexural strength, and splitting tensile strength with minimum cement content for Ultra High Performance Green Concrete (UHPGC) at 28 days. To harness sustainability, ultra-fine Palm Oil Fuel Ash (UPOFA) was employed as a substitute binder at 0%, 15%, 30%, and 45% of the cement mass of UHPGC production. Besides, Silica Fume (SF) substituted from the remaining cement mass with several percentages of 0%, 10%, 15%, and 20%. The experimental results showed the UHPGC (M13) mixture exhibited the greatest compressive, flexural, and splitting tensile strengths, registering 154.8 MPa, 32.18 MPa, and 11.1 MPa, respectively. For the RSM approach, there was a high degree of agreement between the model-predicted values and the actual. Thereby, the models developed had statistical significance and demonstrated a satisfactory correlation value (R2) of 98.11, 96.08, and 98.21 for compressive, flexural, and splitting tensile strength at 28 days, respectively. Hence, an effective strategy for enhancing the mix design of UHPGC could involve the application of the RSM method as an optimization technique. Based on this innovation, SF could extend UPOFA use in green concrete manufacturing, lowering waste volume disposal and costly power consumption for cement manufacture, thereby fostering concrete sustainability.