ISEP - Departamento de Matemática
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Browsing ISEP - Departamento de Matemática by Author "Alvim, M.R."
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- A case study on the eco-efficiency performance of a composite processing industry: evaluation and quantification of potential improvementsPublication . Ribeiro, M.C.S.; Meira Castro, Ana C.; Silva, F.J.G.; Meixedo, JP; Oliveira, L.; Alvim, M.R.; Fiúza, A.; Dinis, M.L.In this study, an attempt was made in order to measure and evaluate the eco-efficiency performance of a pultruded composite processing company. For this purpose the recommendations of World Business Council for Sustainable Development (WCSD) and the directives of ISO 14301 standard were followed and applied. The main general indicators of eco-efficiency, as well as the specific indicators, were defined and determined. With basis on indicators’ figures, the value profile, the environmental profile, and the pertinent eco-efficiency ratios were established and analyzed. In order to evaluate potential improvements on company eco-performance, new indicators values and eco-efficiency ratios were estimated taking into account the implementation of new proceedings and procedures, at both upstream and downstream of the production process, namely: i) Adoption of a new heating system for pultrusion die-tool in the manufacturing process, more effective and with minor heat losses; ii) Recycling approach, with partial waste reuse of scrap material derived from manufacturing, cutting and assembly processes of GFRP profiles. These features lead to significant improvements on the sequent assessed eco-efficiency ratios of the present case study, yielding to a more sustainable product and manufacturing process of pultruded GFRP profiles.
- Eco-efficiency approaches towards a sustainable composite materials manufacturing industryPublication . Fiúza, António; Ribeiro, M. C. S.; Meira Castro, Ana C.; Silva, F.; Meixedo, JP; Alvim, M.R.; Oliveira, L.In this study the potential eco-efficiency performance of a pultrusion manufacturing company was assessed. Indicators values and eco-efficiency ratios were estimated taking into account the implementation of new proceedings and procedures in the production process of glass fibre reinforced polymers (GFRP) pultrusion profiles. Two different approaches were foreseen: 1)Adoption of a new heating system for pultrusion die in the manufacturing process, more effective and with minor heat losses; and 2) Recycling approach, with partial waste reuse of scrap material derived from manufacturing, cutting and assembly processes of GFRP profiles. These features lead to significant improvements on the sequent assessed eco-efficiency ratios of the present case study, yielding to a more sustainable product and manufacturing process of pultruded GFRP profiles.
- Experimental study on polyester based concretes filled with glass fibre reinforced plastic recyclates – a contribution to composite materials sustainabilityPublication . Ribeiro, M. C. S.; Fiúza, António; Dinis, M.L.; Meira Castro, Ana C.; Silva, F.J.G.; Meixedo, JP; Alvim, M.R.The development and applications of thermoset polymeric composites, namely fibre reinforced plastics (FRP), have shifted in the last decades more and more into the mass market [1]. Despite of all advantages associated to FRP based products, the increasing production and consume also lead to an increasing amount of FRP wastes, either end-of-lifecycle products, or scrap and by-products generated by the manufacturing process itself. Whereas thermoplastic FRPs can be easily recycled, by remelting and remoulding, recyclability of thermosetting FRPs constitutes a more difficult task due to cross-linked nature of resin matrix. To date, most of the thermoset based FRP waste is being incinerated or landfilled, leading to negative environmental impacts and supplementary added costs to FRP producers and suppliers. This actual framework is putting increasing pressure on the industry to address the options available for FRP waste management, being an important driver for applied research undertaken cost efficient recycling methods. [1-2]. In spite of this, research on recycling solutions for thermoset composites is still at an elementary stage. Thermal and/or chemical recycling processes, with partial fibre recovering, have been investigated mostly for carbon fibre reinforced plastics (CFRP) due to inherent value of carbon fibre reinforcement; whereas for glass fibre reinforced plastics (GFRP), mechanical recycling, by means of milling and grinding processes, has been considered a more viable recycling method [1-2]. Though, at the moment, few solutions in the reuse of mechanically-recycled GFRP composites into valueadded products are being explored. Aiming filling this gap, in this study, a new waste management solution for thermoset GFRP based products was assessed. The mechanical recycling approach, with reduction of GFRP waste to powdered and fibrous materials was applied, and the potential added value of obtained recyclates was experimentally investigated as raw material for polyester based mortars. The use of a cementless concrete as host material for GFRP recyclates, instead of a conventional Portland cement based concrete, presents an important asset in avoiding the eventual incompatibility problems arisen from alkalis silica reaction between glass fibres and cementious binder matrix. Additionally, due to hermetic nature of resin binder, polymer based concretes present greater ability for incorporating recycled waste products [3]. Under this scope, different GFRP waste admixed polymer mortar (PM) formulations were analyzed varying the size grading and content of GFRP powder and fibre mix waste. Added value of potential recycling solution was assessed by means of flexural and compressive loading capacities of modified mortars with regard to waste-free polymer mortars.
- Mix design process of polyester polymer mortars modified with recycled GFRP waste materialsPublication . Ribeiro, M. C. S.; Fiúza, António; Dinis, M. L.; Meira Castro, Ana C.; Silva, F.J.G.; Meixedo, JP; Alvim, M.R.In this study, the effect of incorporation of recycled glass fibre reinforced plastics (GFRP) waste materials, obtained by means of shredding and milling processes, on mechanical behaviour of polyester polymer mortars (PM) was assessed. For this purpose, different contents of GFRP recyclates, between 4% up to 12% in weight, were incorporated into polyester PM materials as sand aggregates and filler replacements. The effect of the addition of a silane coupling agent to resin binder was also evaluated. Applied waste material was proceeding from the shredding of the leftovers resultant from the cutting and assembly processes of GFRP pultrusion profiles. Currently, these leftovers as well as non-conform products and scrap resulting from pultrusion manufacturing process are landfilled, with additional costs to producers and suppliers. Hence, besides the evident environmental benefits, a viable and feasible solution for these wastes would also conduct to significant economic advantages. Design of experiments and data treatment were accomplish by means of full factorial design approach and analysis of variance ANOVA. Experimental results were promising toward the recyclability of GFRP waste materials as partial replacement of aggregates and reinforcement for PM materials, with significant improvements on mechanical properties of resultant mortars with regards to waste-free formulations.
- On the recyclability of glass fiber reinforced thermoset polymeric composites towards the sustainability of polymers' industryPublication . Ribeiro, M.C.S.; Dinis, M.L.; Meira Castro, Ana C.; Fiuza, A.; Meixedo, JP; Ferreira, A.; Alvim, M.R.Considering the added value of recycling solution assessed by an evaluation of flexural and compressive loading capacity of PC specimens modified with mechanically recycled GFRP wastes, as well as the inherent environmental and economic benefits, the incorporation of GFRP recyclates into PC materials has been revealed as a viable technological option for the sustainability of the GFRP polymers’ industry. Nevertheless, the recyclability of composite materials is complex and is sometimes seen as a key barrier to the adoption of these materials in some markets. One of the few successful applications, was developed by Reprocover, in Belgium, and it has been commercialized since 2011. In addition, the recently investigation line that was started and concerning the GFRP recyclates into PC materials also called the attention of Global Fiberglass SolutionsTM group. Even so, and although all the efforts that had been done on developing cost-effective recycling routes, GFRP wastes still remain mired by the scarceness of reliable outlet markets for the recyclates and clearly developed recycling paths between waste producers and potential consumers for the recyclates. However, it is foreseen that this scenario will change in the next few years as strong investments are being made in this field. The innovation in this field has just started, providing as this way a source of new opportunities.
- Recycling Approach towards Sustainability Advance of Composite Materials’ IndustryPublication . Ribeiro, M.C.S.; Fiuza, A.; Ferreira, A.; Dinis, M.L.; Meira Castro, Ana C.; Meixedo, JP; Alvim, M.R.Worldwide volume production and consumption of engineered composite materials, namely fiber reinforced polymers (FRP), have increased in the last decades, mostly in the construction, automobile, aeronautic and wind energy sectors. This rising production and consumption have also led to an increasing amount of FRP waste, either end-of-life (EoL) products or manufacturing rejects. Taking into account the actual and impending EU framework on waste management, in which clear targets are set with concrete measures to ensure effective implementation, landfill and incineration will be progressively unavailable as traditional end-routes for this kind of waste. Recycling techniques and end-use applications for the recyclates have been investigated over the past twenty years, but even so, more cost-effective and feasible market outlets for the recyclates should be identified that meet both the economic and the environmental points of view. This paper is aimed at enclosing and summarizing an update overview regarding all these issues: current legislation, recycling techniques and end-use applications for the recyclates. Additionally, as a case study, the assessment of the potential improvements that could be made on the eco-efficiency performance (sustainability) of a typical FRP composite materials’ industry by recycling and re-engineering process approaches is also reported.
- Recycling of pultrusion production waste into innovative concrete-polymer composite solutionsPublication . Ribeiro, Maria Cristina Santos; Fiúza, A.; Meira Castro, Ana C.; Silva, F.J.G.; Meixedo, JP; Dinis, M.L.; Costa, C.; Ferreira, F.; Alvim, M.R.In this study, the added value resultant from the incorporation of pultrusion production waste into polymer based concretes was assessed. For this purpose, different types of thermoset composite scrap material, proceeding from GFRP pultrusion manufacturing process, were mechanical shredded and milled into a fibrous-powdered material. Resultant GFRP recyclates, with two different size gradings, were added to polyester based mortars as fine aggregate and filler replacements, at various load contents between 4% up to 12% in weight of total mass. Flexural and compressive loading capacities were evaluated and found better than those of unmodified polymer mortars. Obtained results highlight the high potential of recycled GFRP pultrusion waste materials as efficient and sustainable admixtures for concrete and mortar-polymer composites, constituting an emergent waste management solution.
- Sustainability Improvement of a composite materials’ industry through recycling and re-engineering process approachesPublication . Ribeiro, M.C; Fiúza, A.; Meira Castro, Ana C.; Silva, F.J.G.; Meixedo, JP; Dinis, M.L.; Alvim, M.R.This case study was aimed at measuring and assessing the potential improvements that could be made on the eco-efficiency performance of a composite materials’ industry, specifically a glass fibre reinforced plastic (GFRP) pultrusion manufacturing company. For this purpose, all the issues involved in the pultrusion process of GFRP profiles were analysed, the current ecoefficiency performance of the company was determined, all the procedures applied in the production process were revised, and improvement strategies were planned and investigated with basis on the performed analysis. The new eco-efficiency ratios were estimated taking into account the implementation of new proceedings and procedures through re-engineering the manufacturing process and recycling approaches. These features lead to significant improvements on the sequent assessed eco-efficiency ratios, yielding to a more sustainable product and manufacturing process of pultruded GFRP profiles.