Assessing Freeze-Thaw Damage in Segmental Retaining Walls Units by Mass Loss, Moisture Gain, and Relative Dynamic Modulus

Abstract

Segmental retaining walls (SRWs) constructed of dry-cast concrete masonry units are used in transportation-related applications for which freeze-thaw (FT) durability is evaluated on the basis of percent mass-loss accumulated after multiple FT cycles as per ASTM C1262. This study compared mass loss, mass gain owing to absorption during (FT) exposure, and relative dynamic modulus (RDM) as per ASTM C215. Application of RDM required accounting for the influence of the shape and moisture content of SRW coupons on resonant frequency, with corrections that are likewise applicable to ASTM C666 for ordinary concrete. It was demonstrated that mass loss does not exclusively indicate surface damage, and the relationship between mass loss and RDM is unique to each specimen. Mass gain (as moisture absorption) during testing emerged as a key index of damage, with rapid escalation of mass loss and reduction in RDM at the number of FT cycles required to increase the moisture content of the residual coupon by about 1%.