Influence of water and frost on the performance of natural and recycled materials used in unpaved roads and road shoulders

Abstract

Abstract In recent years, recycled materials from construction and demolition waste (C&D materials) have gained ever more importance as secondary construction materials in civil engineering, especially for road construction purposes. Their use in high-grade applications is an important contribution to a circular economy. However, from a technical viewpoint, reservations remain about the use of such materials. Such reservations typically concern their performance when exposed to water and frost. The aim of this study was to evaluate the field performance of unbound mixed C&D materials used in surface applications like road shoulders or unpaved roads and exposed to the weather conditions of central Europe and to compare the mixed C&D material with two natural reference materials. Two mixed C&D materials and two natural reference materials were field compacted and exposed to the weather during the winter of 2017/2018 and early summer of 2018. The parameters monitored during the period of observation were dry density, stiffness and particle breakdown due to weathering. The results highlight the possible technical benefits of using C&D materials derived from construction and demolition waste instead of natural raw materials in applications such as road shoulders or unpaved roads.