Investigating the use of isothermal calorimetry for predicting physical properties of cements

Abstract

Isothermal calorimetry is a useful technique for studying the cement hydration process that measures the heat flow of cement paste during hydration. Standard cement properties, such as compressive strength, setting times and compatibility can be derived from calorimetry investigation. This becomes relevant in assisting with monitoring the strength development during construction activities and studying the thermal related behaviour of concrete structures. During this study, the heat generated from the cement hydration reactions was investigated of four different cement types, namely CEM II/B-V 32.5N, CEM II/B-V 42.5N, CEM II/A-M (S-V) 42.5R and CEM I 52.5N. Correlations between the calorimeter results and the (i) initial setting time and final setting time; (ii) 28 day compressive strength and; (iii) fineness, were established for the cement types investigated. With the exception of early-day strength, the results indicated strong correlations between the investigated parameters and the cement hydration curves. This was particularly the case for the setting time of the cements with an R2 value of 0.82 and 0.89 for the initial and final setting times respectively.