LAUSR

As concerns on environmental issues are consistently escalating in the perspective of establishing sustainable and environmental-friendly construction in the construction industry, one prominent approach to address this agenda is the application of recycled aggregate concrete (RAC) to concrete production. However, this particular concrete possesses different physical and mechanical properties from those of normal concrete, raising the difficulty of proper understanding and implementation in real-world practice. Accordingly, these shortcomings have drawn the inspiration in this research to devote efforts in deriving an accurate formulation of RAC elastic modulus which is contemplated as one crucial problem relevant to RAC properties. Furthermore, this research proposed symbiotic polyhedron operation tree (SPOT) which incorporated Symbiotic Organisms Search 2.0 and polyhedron operation tree together to develop the prediction model. From result findings and several analyses conducted, the proposed model has shown superiority among other applied methods in terms of stability and robustness. SPOT provides the best RMSE, MAE, MAPE, R, and R 2 values in testing data with major difference. Moreover, the final developed model of SPOT which is interpreted as the RAC elastic modulus equation consists of all input variables constructed in the equation. Hence, having the high accuracy and capability to construct relationship between RAC properties, this model conclusively demonstrated an auspicious capability in accomplishing the objectives specified in this research, especially within this research scope of RAC.