Performance of Conventional AAR-Reactivity Testing Methods to Evaluate Portland Limestone Cement Mixtures

Concrete construction is currently facing a significant challenge to reduce its environmental impact to minimal levels. Portland cement (OPC), the major contributor towards concrete’s carbon footprint, is increasingly being replaced or blended with supplementary cementitious materials (SCMs), alternative materials, and/or by-products; among these, the use of limestone fillers interground with PC resulting in Portland limestone cement (PLC) is probably the most accepted trend by the market. The full implications of PLC in alkali-aggregate reaction (AAR) contexts, however, remain to be understood, demanding the evaluation of current testing methods (i.e., AMBT and CPT) for assessing the potential reactivity of aggregates and mixtures when incorporating PLC. By a comparative analysis of expansion, dynamic modulus of elasticity, and damage rating index over time (i.e., 1 and 6 moths) for both OPC and PLC mortar and concrete, similar kinetics between the two cement types were observed. Yet, PLC has shown different performances depending on aggregate reactivity level.