Polypropylene geotextiles in marine environments: How long will they last?

Significance 

Recent material development has seen geosynthetics dominate many civil engineering works owing to the suitable attributes they possess, namely: ease of application, economical, low environmental impact and high efficiency. These polymeric materials are of utmost importance and of much interest when it comes to coastal developments such as dykes, jetties, groynes, artificial reefs and seawalls. Such torturous outdoor applications demand rigorous material testing. Durability testing of geosynthetics in in-situ conditions is normally time consuming and unsuitable when quick results are needed. Nonetheless, since the tests are carried out under real degradation conditions, they provide reliable and accurate information regarding the durability of geosynthetics. Unfortunately, despite the widespread utilization of geosynthetics in coastal engineering structures, very few papers have been published in relation to their degradation in marine environments.

To this note, University of Porto researchers (José Ricardo Carneiro, Miguel Morais and Maria de Lurdes Lopes) evaluated the resistance of three nonwoven polypropylene (PP) geotextiles with different stabilization packages against seawater, weathering and action of tides. They aimed at determining the effects of the various degrading agents in relation to the physical and mechanical properties of the geotextiles. In addition, they evaluated the effects of the stabilization package in the degradation suffered by the geotextiles. Their work is currently published in the research journal, Construction and Building Materials.

The research work as undertaken entailed the exposure of three nonwoven PP geotextiles with different stabilization packages to seawater, weathering and action of tides in inherent marine conditions. The exposures were carried out in Portugal for a period of 36 months.

The authors observed that weathering contributed to the highest damage in the geotextiles. Additionally, they noted that the weathering resistance of the geotextiles was highly enhanced by Chimassorb 944 and carbon black (two chemical additives). Moreover, it was also seen that the geotextiles had a good resistance against the action of seawater. Lastly, the research team recorded that algae and dirt that accumulated in the nonwoven structures during the exposure to the action of tides, guarded the geotextiles from UV-degradation.

In summary, their study presented an in-depth assessment of the behavior of PP geotextiles in marine environments. Generally, they observed that based on the outdoor degradation tests undertaken, some notable changes in the physical and mechanical properties of three nonwoven geotextiles were revealed. Furthermore, the deterioration of the physical and mechanical properties of the geotextiles during the exposure to weathering were mainly attributed to the damaging effects of UV radiation. Altogether, the PP geotextiles present a quite good resistance against the action of seawater.

Polypropylene geotextiles in marine environments-Advances in Engineering

About the author

José Ricardo Carneiro (PhD in Environmental Engineering, MSc in Chemistry) is a researcher at the University of Porto (Faculty of Engineering) at the Institute of R&D in Structures and Construction. He authored more than 80 scientific papers in journals and conference proceedings and more than 140 presentations in scientific conferences.

He participated in 6 research projects about geosynthetics and currently is the co-principal researcher of project GeoSynergism (Evaluation of synergic effects in the degradation of geosynthetics). José Ricardo Carneiro is co-inventor of the Portuguese patent nº 104126 (Equipment and method for thermo-oxidation testing of geosynthetics) and has supervised 9 research fellows (MSc and research initiation).

About the author

Miguel Morais (MSc in Civil Engineering) is a Civil Engineer at the Azores Port Authority. His work is interdisciplinary and focuses on the following key areas: project manager, construction supervisor and structural designer, mostly in large-scale marine projects, such as cruise terminals, commercial ports, piers, marinas, jetties and mooring equipment. He is also a port facility security officer, responsible for the shore-to-ship contacts regarding security. Miguel Morais participated in project GeoChem (Durability of geosynthetics exposed to physical and chemical agents).

About the author

Maria de Lurdes Lopes (PhD in Civil Engineering) is a Full Professor at the Faculty of Engineering of the University of Porto (FEUP), Head of the Laboratories of Geosynthetics (LGS) and Construction Materials (LEMC) and Coordinator of the research line “New construction materials. Recycling and valorization” of the Institute of R&D in Structures and Construction.

Maria de Lurdes Lopes authored more than 350 scientific publications in books, chapter of books, journals and conference proceedings. She is co-inventor of the Portuguese patent nº 104126 (Equipment and method for thermo-oxidation testing of geosynthetics) and was responsible for the development of 15 prototype test-equipment, 7 pilot plants and 2 computational applications in the field of geosynthetics and environment. Since 1997, was principal researcher of 21 research projects and team member of 10. She supervised 95 fellows of Post-PhD, PhD, MSc and research initiation.

Maria de Lurdes Lopes was Council Member of the International Geosynthetics Society (IGS) (2000-2004) and President/Vice-President of the Portuguese Chapter of IGS (2002-2012). Portuguese delegate to: the European Activities Committee of IGS (2000-2012); the CEN/TC 189 (European Committee for Standardization – Technical Committee on Geosynthetics) (1994-2000); the ISSMGE TC 215 (International Society of Soil Mechanics and Geotechnical Engineering – Technical Committee on Environmental Geotechnics) (since 1995).

Reference

José Ricardo Carneiro, Miguel Morais, Maria de Lurdes Lopes. Degradation of polypropylene geotextiles with different chemical stabilizations in marine environments. Construction and Building Materials, volume 165 (2018) page 877–886.

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