Study of the effects of phase change materials in concrete of pavement with terms of mechanical properties and durability Zahra eslaminia z.eslaminia@cc.iut.ac.ir October, 20, 2020 Department of Civil Engineering Isfahan University of Technology, Isfahan 84156-83111, Iran Degree: M.Sc Language: Farsi Supervisor: Dr. Morteza Madhkhan madhkhan@cc.iut.ac.ir Cold and icy winter’s climatic condition in the western and northwestern regions in Iran imposes significant annual maintenance costs of the road industry. One of the most important environmental factors that cause irreparable damage to concrete pavements is the de-icing operation of the pavement concrete surface, such as the use of deicing salt and freeze-thaw cycles. Investigating the effects of freeze-thaw cycles on concrete durability and providing solutions to increase pavement durability against this phenomenon has been an important issue in the past few years. Recently, phase change materials have been considered due to their ability to absorb and release significant amounts of latent heat during the phase change process. Using phase change materials is one of the new solutions to increase the durability of concrete against freeze-thaw cycles, as well as de-icing the concrete surface without the use of deicing salt and its destructive effects on the environment and the durability of pavement concrete. In the current study, Lica and Scoria aggregates were used as carriers of phase change material (polyethylene glycol grade 400), by replacing lightweight coarse and fine aggregates with normal coarse and fine aggregate in various mixing designs and the mechanical properties and durability of concrete have been investigated. Compressive strength tests lasted of 7, 28 and 90 days, flexural strength of 28 days. Additionally the Brazilian tensile strength of 28 days as well as durability tests including water absorption, permeability and freeze-thaw cycles have been performed. According to the results of the experiments, the mechanical properties have decreased with increasing the amount of aggregate containing the phase change material in the concrete. Nevertheless, concrete with a compressive strength of more than 25 MPa is still within the range of structural use in all mixing designs. Increasing the amount of aggregates containing phase change material in concrete improves the durability characteristics and the percentage of water absorption has decreased to 46% and permeability to 34%. The results also showed that the process of decreasing the compressive strength of the samples slows down after the application of freeze-thaw cycles. Also, the compressive strength drop due to freeze-thaw cycles is improved by up to 24%. Key Words Concrete pavement, Phase change materials, Lightweight aggregate, Mechanical properties, Durability characteristics.