An experimental study on the effects of mix design parameters, test methods, and time-dependence of chloride penetration in concrete

Abstract

Prescriptive durability approaches have proven insufficient to ensure the designed service life of reinforced concrete structures, particularly in highly aggressive environments. Consequently, several codes introduced performance-based specifications to promote more durable designs. These approaches rely on assessing concrete durability-related properties that reflect how the material performs under specific exposure conditions, known as durability indicators. Such parameters are directly influenced by the concrete constituent materials and mix design parameters. Understanding the effects of these factors is therefore essential for developing designs that enhance structural performance and durability. This paper assesses the behavior of 28 concrete mixes produced with different materials and specifications. The influences of various binder systems and mix design parameters on properties directly related to resistance to chloride ingress are evaluated, including chloride migration, electrical resistivity, and water absorption. Different cement types, mineral additions, water/cement and water/binder ratios, and dry mortar contents are adopted. The results show that prescriptive parameters are relevant for concretes with similar binder systems, while differences between distinct binder groups are mainly controlled by the chemical properties of the binders. In this sense, the findings contribute to bridging prescriptive mix design parameters and performance-based durability approaches, highlighting the importance of binder characteristics for a more consistent interpretation of concrete durability indicators under chloride penetration.