Pull-out response of a geogrid buried in recycled sands

Recycled construction and demolition waste (RCDW) has demonstrated geotechnical properties that encourage it to be used in reinforced soil structures (RSS) with geosynthetics. However, the interaction between RCDW and reinforcements needs to be better understood, given its importance for design. This paper presents a qualitative study on the interaction between geogrid and recycled sands by means of pull-out tests performed on small equipment. Tests with the same degree of compaction and a geogrid buried in different types of recycled and natural sands (for comparison purposes) were performed. The characterisation of the materials was carried out in the laboratory and the variability of their geotechnical properties was evaluated. In addition, fill material moisture content was investigated as another potential factor influencing soil-geogrid interface shear. The results of the pull-out tests demonstrated the specific influences of the factors investigated. The comparative study showed that recycled sands can be suitable materials to be used as backfill in geosynthetic reinforced soil structures, meeting physical, mechanical and environmental requirements for this kind of work.