Short-term tensile behaviour of three geosynthetics after exposure to Recycled Construction and Demolition materials

Abstract

Designing and building structures and infrastructures with alternative and environmentally friendly materials is, nowadays, an important step towards a more sustainable society. Recycled Construction and Demolition (C&D) materials have been considered as alternative materials in different civil engineering applications, such as unbound pavement layers and structural embankments, in which geosynthetics are also frequently applied. If the durability of geosynthetics is an important issue when conventional materials are used, it becomes more relevant when utilising alternative materials. This paper presents and discusses the chemical and environmental degradation induced by a recycled C&D material on the short-term tensile behaviour of three geosynthetics used typically as reinforcement material (two geogrids and a high-strength geotextile), after 24 months of exposure. For comparison purposes, geosynthetics samples were also exposed to a natural soil. The physical and environmental characterization of the recycled C&D material are presented and the tensile behaviour of intact (as-received) samples, immediately exhumed samples and exhumed samples after 24 months of exposure are characterized and discussed. To evaluate the potential damage in more detail, Scanning Electron Microscope (SEM) analyses were carried out. Regardless of the geosynthetic type and exposure condition, the geosynthetic's tensile strength decreased after 24-month exposure. This loss of tensile strength was insignificant for the high density polyethylene geogrid and higher for the geotextile. The effect of exposing the geosynthetics to the recycled C&D material for 24 months had some relevance only for geotextile. For both geogrids, the loss of strength for the specimens immediately exhumed and exposed through 24 months is comparable. In general, the exposure to the recycled C&D material or to the soil induced similar effects.