Use of Mixed Construction and Demolition Recycled Materials in Geosynthetic Reinforced Embankments

Abstract

The use of construction and demolition (C&D) recycled materials in the construction industry represents an important step towards a more sustainable future and, simultaneously, represents a new market opportunity to be explored. In the last years, several case studies relating to the application of C&D recycled materials have emerged, mainly, in base and sub-base layers of the roadway infrastructures and in concrete production. This papers deals with the use of fine mixed recycled aggregates as filling material of geosynthetic reinforced embankments. The physical, mechanical and environmental characterization of C&D recycled materials is presented and discussed, as well as, the direct shear behaviour of two C&D materials/geosynthetic interfaces. The C&D recycled material was collected from a Portuguese recycling plant and comes from non-selected C&D wastes. One geogrid and one high strength geotextile were used to assess the interfaces behaviour. The environmental characterization of the C&D recycled material, carried out through laboratory leaching tests, has not shown any environmental concerns. Direct shear test results have revealed that the increase in C&D recycled material moisture content can measurably reduce the interface shear strength. The shear strength of the C&D material/geosynthetic interface has improved with the degree of compaction increase. The coefficients of interaction reached for C&D material/geosynthetic interfaces, a key factor in the design of geosynthetic reinforced structures, compare well with those found in the literature for soil/geosynthetic interfaces.