Natural weathering of polypropylene geotextiles treated with different chemical stabilisers

Abstract

Weathering (mainly due to solar radiation) may cause unwanted changes in the properties of geosynthetics, affecting their performance and shortening their lifetime. In this work, four nonwoven polypropylene geotextiles were exposed to natural weathering in Portugal during a maximum period of 3 years. The geotextiles were structurally identical, but had different known amounts of a hindered amine light stabiliser and carbon black in their composition. The damage suffered by the geotextiles (caused by weathering) was evaluated qualitatively (by visual inspection) and quantitatively by monitoring changes in their mechanical properties (tensile and static puncture tests). The results, among other findings, showed that: (1) weathering led to the deterioration of the mechanical properties of the geotextiles, (2) the behaviour of the geotextiles was highly dependent on their chemical composition, (3) the weathering resistance of the geotextiles was highly enhanced by the hindered amine light stabiliser and/or by carbon black, (4) a higher amount of the hindered amine light stabiliser (an increase from 0.2% to 0.4%, w/w) led to better weathering resistance and (5) the presence of carbon black (1.08%, w/w) in combination with the hindered amine light stabiliser (0.2%, w/w) resulted in the best protection against weathering.