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- New end-use application for GFRP recyclates as reinforcement for concrete-polymer materials’Publication . Ribeiro, M. C. S.; Meira Castro, Ana C.; Fiúza, António; Dinis, M. L.; Silva, Francisco J. G.; Meixedo, João PauloGlass fibre-reinforced plastics (GFRP), nowadays commonly used in the construction, transportation and automobile sectors, have been considered inherently difficult to recycle due to both: cross-linked nature of thermoset resins, which cannot be remolded, and complex composition of the composite itself, which includes glass fibres, matrix and different types of inorganic fillers. Presently, most of the GFRP waste is landfilled leading to negative environmental impacts and supplementary added costs. With an increasing awareness of environmental matters and the subsequent desire to save resources, recycling would convert an expensive waste disposal into a profitable reusable material. There are several methods to recycle GFR thermostable materials: (a) incineration, with partial energy recovery due to the heat generated during organic part combustion; (b) thermal and/or chemical recycling, such as solvolysis, pyrolisis and similar thermal decomposition processes, with glass fibre recovering; and (c) mechanical recycling or size reduction, in which the material is subjected to a milling process in order to obtain a specific grain size that makes the material suitable as reinforcement in new formulations. This last method has important advantages over the previous ones: there is no atmospheric pollution by gas emission, a much simpler equipment is required as compared with ovens necessary for thermal recycling processes, and does not require the use of chemical solvents with subsequent environmental impacts. In this study the effect of incorporation of recycled GFRP waste materials, obtained by means of milling processes, on mechanical behavior of polyester polymer mortars was assessed. For this purpose, different contents of recycled GFRP waste materials, with distinct size gradings, were incorporated into polyester polymer mortars as sand aggregates and filler replacements. The effect of GFRP waste treatment with silane coupling agent was also assessed. Design of experiments and data treatment were accomplish by means of factorial design and analysis of variance ANOVA. The use of factorial experiment design, instead of the one-factor-at-a-time method is efficient at allowing the evaluation of the effects and possible interactions of the different material factors involved. Experimental results were promising toward the recyclability of GFRP waste materials as aggregates and filler replacements for polymer mortar, with significant gain of mechanical properties with regard to non-modified polymer mortars.
- 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.
- New recycling approaches for thermoset polymeric composite wastes – an experimental study on polyester based concrete materials filled with fibre reinforced plastic recyclatesPublication . Ribeiro, M. C. S.; Fiúza, António; Meira Castro, Ana C.; Dinis, M. L.; Silva, Francisco J. G.; Meixedo, João PauloIn this study, a new waste management solution for thermoset glass fibre reinforced polymer (GFRP) based products was assessed. Mechanical recycling approach, with reduction of GFRP waste to powdered and fibrous materials was applied, and the prospective added-value of obtained recyclates was experimentally investigated as raw material for polyester based mortars. Different GFRP waste admixed mortar formulations were analyzed varying the content, between 4% up to 12% in weight, of GFRP powder and fibre mix waste. The effect of incorporation of a silane coupling agent was also assessed. Design of experiments and data treatment was accomplished through implementation of full factorial design and analysis of variance ANOVA. Added value of potential recycling solution was assessed by means of flexural and compressive loading capacity of GFRP waste admixed mortars with regard to unmodified polymer mortars. The key findings of this study showed a viable technological option for improving the quality of polyester based mortars and highlight a potential cost-effective waste management solution for thermoset composite materials in the production of sustainable concrete-polymer based products.
- Re-use assessment of thermoset composite wastes as aggregate and filler replacement for concrete-polymer composite materials: a case study regarding GFRP pultrusion wastesPublication . C. S. Ribeiro, Maria; Meira Castro, Ana C.; Silva, Francisco; Santos, Jorge M.; Meixedo, Joao Paulo; Fiúza, António; Dinis, M. L.; Alvim, Mário RuiGlass fibre-reinforced plastics (GFRP), nowadays commonly used in the construction, transportation and automobile sectors, have been considered inherently difficult to recycle due to both the cross-linked nature of thermoset resins, which cannot be remoulded, and the complex composition of the composite itself, which includes glass fibres, polymer matrix and different types of inorganic fillers. Hence, to date, most of the thermoset based GFRP waste is being incinerated or landfilled leading to negative environmental impacts and additional costs to producers and suppliers. With an increasing awareness of environmental matters and the subsequent desire to save resources, recycling would convert an expensive waste disposal into a profitable reusable material. In this study, the effect of the incorporation of mechanically recycled GFRP pultrusion wastes on flexural and compressive behaviour of polyester polymer mortars (PM) was assessed. For this purpose, different contents of GFRP recyclates (0%, 4%, 8% and 12%, w/w), with distinct size grades (coarse fibrous mixture and fine powdered mixture), were incorporated into polyester PM as sand aggregates and filler replacements. The effect of the incorporation of a silane coupling agent was also assessed. Experimental results revealed that GFRP waste filled polymer mortars show improved mechanical behaviour over unmodified polyester based mortars, thus indicating the feasibility of GFRP waste reuse as raw material in concrete-polymer composites.
- 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.
- A case study on the improvement of eco-efficiency ratios: application to a composite processing industryPublication . Ribeiro, M. C. S.; Meira Castro, Ana C.; Silva, Francisco J. G.; Alvim, Mário Rui; Costa, C.; Fiúza, António; Dinis, M. L.; Meixedo, João PauloThe World Business Council for Sustainable Development (WBCSD) defines Eco-Efficiency as follows: ‘Eco- Efficiency is achieved by the delivery of competitively priced-goods and services that satisfy human needs and bring quality of life, while progressively reducing ecological impacts and resource intensity throughout the life-cycle to a level at least in line with the earth’s estimated carrying capacity’. Eco-Efficiency is under this point of view a key concept for sustainable development, bringing together economic and ecological progress. Measuring the Eco-Efficiency of a company, factory or business, is a complex process that involves the measurement and control of several and relevant parameters or indicators, globally applied to all companies in general, or specific according to the nature and specificities of the business itself. In this study, an attempt was made in order to measure and evaluate the eco-efficiency of a pultruded composite processing company. For this purpose the recommendations of WBCSD [1] and the directives of ISO 14301 standard [2] were followed and applied. The analysis was restricted to the main business branch of the company: the production and sale of standard GFRP pultrusion profiles. The main general indicators of eco-efficiency, as well as the specific indicators, were defined and determined according to ISO 14031 recommendations. With basis on indicators’ figures, the value profile, the environmental profile, and the pertinent eco-efficiency’s ratios were established and analyzed. In order to evaluate potential improvements on company eco-performance, new indicators values and ecoefficiency ratios were estimated taking into account the implementation of new proceedings and procedures, both in upstream and downstream of the production process, namely: a) Adoption of new heating system for pultrusion die in the manufacturing process, more effective and with minor heat losses; b) Implementation of new software for stock management (raw materials and final products) that minimize production failures and delivery delays to final consumer; c) Recycling approach, with partial waste reuse of scrap material derived from manufacturing, cutting and assembly processes of GFRP profiles. In particular, the last approach seems to significantly improve the eco-efficient performance of the company. Currently, by-products and wastes generated in the manufacturing process of GFRP profiles are landfilled, with supplementary added costs to this company traduced by transport of scrap, landfill taxes and required test analysis to waste materials. However, mechanical recycling of GFRP waste materials, with reduction to powdered and fibrous particulates, constitutes a recycling process that can be easily attained on heavy-duty cutting mills. The posterior reuse of obtained recyclates, either into a close-looping process, as filler replacement of resin matrix of GFRP profiles, or as reinforcement of other composite materials produced by the company, will drive to both costs reduction in raw materials and landfill process, and minimization of waste landfill. 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.
- GFRP waste reinforced polymer mortars: a new waste management solution for GFRP scrap materialPublication . Ribeiro, M. C. S.; Meira Castro, Ana C.; Fiúza, António; Dinis, M. L.; Silva, Francisco J. G.; Meixedo, João PauloTo date, glass fibre reinforced polymer (GFRP) waste recycling is very limited and restricted by thermoset nature of binder matrix and lack of economically viable enduse applications for the recyclates. In this study, efforts were made in order to recycle grinded GFRP waste proceeding from pultrusion production scrap, into new and sustainable composite materials. For this purpose, GFRP waste recyclates, a mix of powdered and fibrous materials, were incorporated into polyester based mortars as fine aggregate and filler replacements, at different load contents (between 4% up to 12% of total mass) and particle size distributions. Potential recycling solution was assessed by mechanical behaviour of resultant GFRP waste modified polymer mortars. Test results revealed that GFRP waste filled polymer mortars present improved flexural and compressive behaviour over unmodified polyester based mortars, thus indicating the feasibility of GFRP waste reuse in concrete-polymer composites.
- 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.
- Hybrid thermoset polymeric composites – an Innovation towards sustainabilityPublication . Meira Castro, Ana C.; Ribeiro, M. C. S.; Meixedo, João Paulo; Silva, F.J.G.; Fiúza, A.; Dinis, M.L.; Alvim, M.In this study, a new waste management solution for thermoset glass fibre reinforced polymer (GFRP) based products was assessed. Mechanical recycling approach, with reduction of GFRP waste to powdered and fibrous materials was applied, and the prospective added-value of obtained recyclates was experimentally investigated as raw material for polyester based mortars. Different GFRP waste admixed mortar formulations were analyzed varying the content, between 4% up to 12% in weight, of GFRP powder and fibre mix waste. The effect of incorporation of a silane coupling agent was also assessed. Design of experiments and data treatment was accomplished through implementation of full factorial design and analysis of variance ANOVA. Added value of potential recycling solution was assessed by means of flexural and compressive loading capacity of GFRP waste admixed mortars with regard to unmodified polymer mortars. The key findings of this study showed a viable technological option for improving the quality of polyester based mortars and highlight a potential cost-effective waste management solution for thermoset composite materials in the production of sustainable concrete-polymer based products.
- Saving energy in the GFRP pultrusion processPublication . Silva, Francisco J. G.; Ribeiro, M. C. S.; Meira Castro, Ana C.; Alvim, Mário Rui; Meixedo, João Paulo; Fiúza, António; Dinis, M. L.This study addresses to the optimization of pultrusion manufacturing process from the energy-consumption point of view. The die heating system of external platen heaters commonly used in the pultrusion machines is one of the components that contribute the most to the high consumption of energy of pultrusion process. Hence, instead of the conventional multi-planar heaters, a new internal die heating system that leads to minor heat losses is proposed. The effect of the number and relative position of the embedded heaters along the die is also analysed towards the setting up of the optimum arrangement that minimizes both the energy rate and consumption. Simulation and optimization processes were greatly supported by Finite Element Analysis (FEA) and calibrated with basis on the temperature profile computed through thermography imaging techniques. The main outputs of this study allow to conclude that the use of embedded cylindrical resistances instead of external planar heaters leads to drastic reductions of both the power consumption and the warm-up periods of the die heating system. For the analysed die tool and process, savings on energy consumption up to 60% and warm-up period stages less than an half hour were attained with the new internal heating system. The improvements achieved allow reducing the power requirements on pultrusion process, and thus minimize industrial costs and contribute to a more sustainable pultrusion manufacturing industry.