Table 1: Concrete mix proportioning Materials/Concrete RCC 126 Design strength fck (MPa) 7 Age (days) 180 Cement (kg/m3) 50 Fly ash from Candiota (kg/m3) 20 Water (kg/m3) 130 Fine aggregate – artificial sand (kg/m3) 1191 Coarse aggregate – 25mm (kg/m3) 631 Coarse aggregate – 50mm (kg/m3) 631 Retarding 283R (kg/m3) 1.30