Assessment of Real-Time Freeze-Thaw Durability of Concrete Pavements Containing Low-Temperature Phase Change Materials

Abstract Improvement of concrete pavements in cold regions is a major issue as durability is impacted by frost action and freeze-thaw cycles. In this study, thermal responsive composites were developed to improve freeze-thaw durability of concrete via incorporation of phase change materials (PCM) using two methods: (i) inclusion of PCM in porous network of lightweight aggregates, and (ii) micro-encapsulated PCM. The experimental program consisted of: (i) evaluation of fresh properties of PCM incorporated concrete mixes, (ii) mechanical and water absorption properties assessment of hardened PCM-concrete mixes, and (iii) assessment of thermal performance of PCM concrete slabs at real-time outdoor and environmental simulated conditions. It was found that the inclusion of micro-encapsulated PCM in concrete during wet mixing forms agglomerates and degrades fresh properties, requiring higher volume fraction of cement paste and superplasticizers to achieve desirable flowability and air entrainment. Incorporation methods have a significant influence on strength and durability factors. An estimation using predictive model showed concrete that has PCM stored in lightweight aggregates as storage agents will take 53.68 ~ 61.45 years until it reaches critical degree of saturation, only if. Thermal assessment results of PCM concrete slabs in outdoor conditions and simulated environmental conditions demonstrated that lightweight aggregate infusion of PCM was more suitable for freeze-thaw resilience concrete infrastructure applications. At outdoor scale, PCM-infused concrete reduced the number of freeze-thaw cycles by an average of 39.62 % in comparison to reference concrete with no PCM during two cold seasons.