Influence of Burnability Index on the Strength Progression of Sulphate-resistant Portland Cement Concrete

The study examined the combined effect of the main compounds in Sulphate-Resistant Portland Cement (SRPC), represented by a Burnability Index (B.I.) (C3S/(C4AF+C3A)), on strength progression at different curing temperatures (7°C, 21°C, 34°C). 270 cubic concrete specimens with three different values of B.I. 2.08, 2.81, and 3.21 were applied to the compressive strength test at ages of 1, 2, 4, 7, and 28 days to monitoring the rate of strength progression (K-value) and determining the activation energy, following ASTM C1074 procedure. The study additionally examined the effect of cement quantity in concrete on strength progression by testing two concrete design strengths (20 and 35 N/mm²). The results revealed that the concrete compressive strength reduced with the increase of B.I. in cement, especially at the age of 28-day. This reduction was more pronounced in concrete that contained a higher cement quantity (35 N/mm² strength). The B.I. has a significant influence on K-value at low curing temperature (7°C); while this influence decays with higher temperature (34°C). In addition, the increase of B.I. in cement raises the activation energy of concrete, specifically in higher-strength concrete.