Environmental awareness and legislative pressures have made manufacturers responsible for the take-back and end-of-life treatment of their products. Therefore, manufacturers are struggling to find ways to recover maximum value from returned products. This goal can best be achieved by promoting multiple reuse programs as reuse is one of the most effective ways to enhance a sustainable engineering economy. Since the essential goal of the reuse strategy is to reuse parts, the reliability of used parts becomes a core issue. Research indicates that reuse is technologically feasible, associated with a significant manufacturing cost saving, and it does not compromise product quality. However, it is not easy to be applied in reality. There are several uncertainties associated with reuse, the most common is the uncertainty of the product???s quality after use. A widespread implementation of the reuse strategy could be triggered, subject to the availability of reliable methods to assess the useful remaining life of parts. The evolution of such a methodology would play a pivotal role in making decisions on the supply chain process and the recovery value of returned products. Reliability assessment by life cycle data analysis is the basis of this research. The proposed methodology addresses the problem of reliability assessment of used parts by considering two important aspects. It performs statistical as well as condition monitoring data analysis for decision-making on reuse. The analysis is carried out in two stages. Firstly, a wellknown reliability assessment procedure, the Weibull analysis, is applied to analyse time-tofailure data to assess the overall reuse potential of components. In the second stage, the used capacity (actual life) of components is determined by analysing their operating history (condition monitoring data). The linear and nonlinear regression analysis, Kriging procedures and artificial neural networks (ANN) are employed in this stage. Finally, the Weibull analysis and ANNs are integrated to estimate the remaining useful life of components/assemblies of a product at the end of its first life cycle. The model was validated by using life cycle data from consumer products.

This study arises out of the researcher’s experience in the fields of costume and fashion. It develops, through design practice and reflection, a design process for fashion wear made from post-consumer recycled materials. Theoretical analysis provides global, historical, philosophical and design contexts within which to develop an ethos for this variant form of fashion wear designated ReFashion. Differences in design process between conventional fashion and ReFashion are detailed to highlight the significance of provenance of materials in the light of a perceived need to slow down clothing production and consumption. This perception is informed by scientific predictions that failure to engage with urgently needed changes to the prevalent economic paradigm will result in planet earth reaching a tipping point with potentially disastrous results for its inhabitants. Fundamental to the ReFashion ethos is preparedness for a speculative post-apocalyptic future that might render the fashion system unable to operate as it currently does, necessitating a more self-sufficient approach to clothing needs, with an accompanying shift in perceptions of what is deemed fashionable. The theme Survivalist Fantasy provides a lens to bring conceptual and material aspects of the work into focus. Informed by sustainability, Survivalist Fantasy recontextualises a failure of sustainable initiatives on a global scale and their adaptation on a local scale specifically in the arena of clothing.

This study arises out of the researcher’s experience in the fields of costume and fashion. It develops, through design practice and reflection, a design process for fashion wear made from post-consumer recycled materials. Theoretical analysis provides global, historical, philosophical and design contexts within which to develop an ethos for this variant form of fashion wear designated ReFashion. Differences in design process between conventional fashion and ReFashion are detailed to highlight the significance of provenance of materials in the light of a perceived need to slow down clothing production and consumption. This perception is informed by scientific predictions that failure to engage with urgently needed changes to the prevalent economic paradigm will result in planet earth reaching a tipping point with potentially disastrous results for its inhabitants. Fundamental to the ReFashion ethos is preparedness for a speculative post-apocalyptic future that might render the fashion system unable to operate as it currently does, necessitating a more self-sufficient approach to clothing needs, with an accompanying shift in perceptions of what is deemed fashionable. The theme Survivalist Fantasy provides a lens to bring conceptual and material aspects of the work into focus. Informed by sustainability, Survivalist Fantasy recontextualises a failure of sustainable initiatives on a global scale and their adaptation on a local scale specifically in the arena of clothing.

Canadian grown oilseed flax is known for its oils that are used for industrial products. The flax fiber may also have a use as a potential replacement for synthetic fibers as reinforcement in plastic composites. It can also be utilized as a cost effective and environmentally acceptable supplement in the biodegradable composites. Tire rubber is a complex material which does not decompose naturally. As a result, many researchers have been trying to develop new applications for recycling scrap tires. The conversion of flax straw and scrap tire into a profitable product may benefit the agricultural economy, tire recycling market, and our environment. The main goal of this research was to develop a biocomposite material containing recycled ground tire rubber (GTR), untreated flax fiber, and linear low-density polyethylene (LLDPE).<p> In this study, the new biocomposite material was successfully prepared from flax fiber/shives, GTR, and LLDPE through extrusion and compression molding processes. The composites were compounded through a single-screw extruder. Then the pelletized extrudates were hot pressed into the final biocomposites. The properties of the flax fiber-GTR-LLDPE biocomposites were defined by using tearing, tensile, water absorption, hardness, and differential scanning calorimetry (DSC) tests. The effects of the independent variables (flax fiber content and GTR-LLDPE ratio) on each of the dependent variables (tear strength from tearing test, tensile yield strength and Youngs modulus from tensile test, and weight increase from water absorption test) were modeled. The properties of the composites can be predicted by using the mathematical model with known flax fiber content and GTR-LLDPE ratio.<p> The tensile yield strength and stiffness of the biocomposite were improved with the addition of flax fiber. The optimal composition of the biocomposite material (with strongest tensile yield strength or highest Youngs modulus) was calculated by using the model equations. The maximum yield strength was found to exist for a flax fiber content of 10.7% in weight and GTR-LLDPE ratio of one. The largest Youngs modulus was found for a fiber content of 17.7% by weight and the same GTR-LLDPE ratio. Both of these fiber contents were less than the amount that would give a composite with a 2% weight increase in water absorption.

One of the largest product categories within all the electronic products is portable ­computers, also known as notebooks, is slowly replacing stationary computers and is ­predicted to be the mainstream choice in the near future. But the current state of ­notebook shows these products are not accommodated for an effective large scale ­recycling process. As the notebooks are becoming more compact, its inner ­structures have become more complicated. Permanently fastening methods, multi-material ­compositions and many other factors contribute to an ineffective, expensive and tedious recycling process. The goal of the project treated in this report was to investigate the possibilities of a simplified structure adapted for an effective disassembly and recycling process. And to develop a conceptual notebook adapted for the stated purpose. The project resulted in a conceptual notebook named Sixten with an enhanced and ­simplified inner structure. All permanently fastening methods was replaced by ­detachable locking and securing devices. The number of tools required for dismantling was reduced, as the usage of screws. The variation of materials used in the notebook, with ­electrical components apart, is low. These materials, ABS plastics and aluminum were chosen based on their recyclable and processing possibilities. But also because of the durability and desired mechanical properties the structure required. The limited number of materials used in Sixten makes it environmentally beneficial since every material ­requires its own specific recycling process, and by reducing the number of materials energy can be saved on using only a few recycling methods. Sixten fulfills the principals of design for disassembly as a notebook that is easy to ­disassemble in comparison with notebooks on the market today. The disassembly time has been reduced, from the 45 minutes which may be required to fully disassemble a conventional notebook, down to an estimated disassembly time of 6 minutes, which is the time Sixten requires. It is in this short disassembly time where the economic benefits of Sixten lie.

Disposed waste materials remained from demolished buildings have been an environmental problem especially for developing countries. Recycled Cement Concrete (RCC) is one of the abundant components of waste materials that include quality aggregates. Use of RCC in asphalt concrete pavements is economically a feasible option as it not only helps in recycling waste materials but also preserves natural resources by fulfilling the demand for quality aggregate in pavement constructions. However, due to variability in RCC characteristics, a detailed evaluation of its effect on asphalt concrete performance is required. In this study, effect of RCC content on rutting potential of asphalt concrete is investigated using laboratory prepared specimens. Rutting susceptibility of the specimens is determined using repeated creep tests performed in the uniaxial stress mode. Because of the aspect ratio requirements for the repeated creep test, the standard Marshall mix design procedures were modified based on the energy concept by changing the compactor device and the applied design number of blows. The modified specimens were tested to determine a number of parameters that can describe the rutting behavior of the tested mixes. The findings indicate that slope constant and flow number give relatively stronger relationships with rutting behavior as compared to the other rutting parameters. While increasing the RCC content yields improved rutting performance for coarse graded specimens, it dramatically reduces the performance for fine graded specimens.

The aim of this study was to improve the mechanical properties of a recycled grade polypropylene. Polymer blends and nanocomposites were prepared by melt compounding method in a twin screw extruder. Cloisite&reg / 15A, Cloisite&reg / 25A and Cloisite&reg / 30B were used as organoclays, and ethylene-methyl acrylate-glycidyl methacrylate (E-MA-GMA) and maleic anhydride grafted polypropylene (PP-MAH) were used as compatibilizers. The effects of additive concentrations, types of organoclays and compatibilizers, processing conditions, and the compatibilizer to organoclay ratio on the morphology and mechanical, thermal and flow properties were investigated. Organoclay loading over 2 wt% prevented the intercalation mechanism and material properties, even in the presence of compatibilizer, as a consequence of large clay agglomerate formation. E-MA-GMA compatibilizer improved the intercalation ability of the polymer / however a substantial increase in mechanical properties was not obtained. PP-MAH is found to be a better compatibilizer. Processing conditions significantly affected both mechanical properties and morphology. When the processing temperature was decreased and screw speed was increased simultaneously, tensile and impact properties were improved owing to enhanced shear and dispersive forces. TEM analysis revealed that intercalated and delaminated structures were formed with the addition of PP-MAH compatibilizer. In addition to that, as the ratio of PP-MAH to organoclay was increased, more effective dispersion of organoclay was observed and hence resultant improvements in both tensile and impact properties were greater at compatibilizer to organoclay ratio of three. Cloisite&reg / 15A exhibited the highest improvements in mechanical properties, although the degree of organoclay dispersion was better for Cloisite&reg / 25A and particularly for Cloisite&reg / 30B. Melt flow index values were lower compared to pure recycled polypropylene in the presence of organoclay and compatibilizers. DSC analysis indicated no significant change in the melting behavior of the matrix materials.

This research investigates complete recycling and utilization of waste concrete to produce new structural concrete through geopolymerization. The investigation was conducted through both macro-and micro/nano-scale studies. First the geopolymer paste synthesized using a mixture of waste concrete fines (WCF) and class F fly ash (FA) as the source material and a mixture of NaOH solution (N) and Na2SiO3 solution (SS) as the alkaline activating agent was studied. Various NaOH concentrations, SS/N ratios, and WCF contents were used to produce geopolymer paste specimens in order to study their effect on the properties of the geopolymer paste. Uniaxial compression tests were conducted to measure the strength of the geopolymer paste specimens. X-ray diffraction (XRD), scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX), and Fourier transform infrared spectroscopy (FTIR) analyses were performed to investigate the micro/nano-structure, morphology and phase/surface elemental compositions of the geopolymer paste and the effect of calcium (Ca) on them. The results indicate that by using 10 M NaOH solution, SS/N of 2 and 50% WCF, the highest geopolymer paste strength can be obtained. Second, the interfacial transition zones (ITZs) between geopolymer (GP) and recycled aggregates (RA) were studied. Considering that RA consist of the stone particles and the attached paste/mortar from the original ordinary Portland cement (OPC) concrete, both the ITZs between GP and natural aggregate (NA) and those between GP and residual OPC paste/mortar (ROPM) were studied. For comparison, the ITZs between OPC paste and NA and those between OPC paste and ROPM were also investigated. 4-point bending tests were conducted to measure the bonding strength of the different types of ITZs at water to solid (W/S) ratio of 0.30, 0.35 and 0.40 for the geopolymer and OPC pastes after 7 and 14 days curing, respectively. SEM imaging was performed to investigate the microstructure of the ITZs. The results indicate that when NA is used, the bonding strength of both the GP-NA and OPC-NA ITZs decreases with higher water to solid (W/S) ratio. When ROPM is used, higher W/S ratio leads to smaller bonding strength for the GP-ROPM ITZ but greater bonding strength for the OPC-ROPM ITZ. Based on the measured bonding strength values for NA- and ROPM-based ITZs, the bonding strength of the GP-RA and OPC-RA ITZs was estimated by considering the average area coverage of ROPM on the RA surface. The GP-RA ITZ has the highest bonding strength among the different ITZs, implying the great potential for utilizing waste concrete (both the WCF and the RA) to produce geopolymer concrete. Third, based on the studies on geopolymer paste and ITZs, geopolymer concrete (GPC) was produced and studied using WCF and FA as the cementitious material and RA as the aggregate. For comparison, GPC using NA was also produced and studied at similar conditions. Various NaOH concentrations, SS/N ratios, and cement (WCF and FA) to aggregate (C/A) ratios were used to produce GPC specimens in order to study their effect on the behavior of GPC. The effect of water content and curing temperature on the initial setting time and 7-day unconfined compressive strength (UCS) of the GPC was also studied. The results show that the GPC produced from RA has higher UCS than the GPC from NA at both room curing temperature and 35°C curing temperature. Based on this study, it can be concluded that waste concrete can be completely recycled and used to produce new structural concrete based on the geopolymerization technology. Fourth, considering that the Si/Al and Na/Al ratios have great effect on the geopolymerization process and the properties of the final geopolymer product, a study was conducted on copper mine tailings (MT)-based geopolymer containing different amount of aluminum sludge (AS). The results indicate that by including AS and utilizing appropriate amount of NaOH, the UCS can be increased significantly. The main reason is because the addition of AS along with utilization of appropriate amount of NaOH makes both the Si/Al and Na/Al ratios reach the optimum values for geopolymerization, leading to higher degree of geopolymerization and more compact geopolymer microstructure. It is noted that although this study is not directly on waste concrete, it provides useful information for optimizing the design on complete recycling and utilization of waste concrete to produce new GPC. Finally, to better understand the effect of Ca on the geopolymerization process and the properties of geopolymer, molecular dynamics (MD) simulations were performed on geopolymer at different Ca contents. The molecular models at different Ca contents were constructed and uniaxial compression test was then performed on the numerical specimens. The results indicate that MD simulation is an effective tool for studying the effect of Ca on the properties of geopolymer at nano-scale.

One of the current problems faced by mankind is the problem of safe disposal of waste rubber. Statistics show that the number of waste tires is continuously increasing at a very rapid rate. Since rubber materials do not decompose easily (due to their crosslinked structure), they end up being a serious ???environmental problem???. An intuitive solution to prevent the accumulation of the scrap tires is to continuously reuse them. A new patented reclamation method was discovered in our laboratory, which makes use of a twin screw extruder (TSE) in order to produce reclaimed rubber (referred as devulcanized rubber (DR) from here on) of very high quality. Also, this method has proven to be more economical than other commercial reclaiming methods. Products made solely from a reclaimed material face challenges from those made by virgin materials because of relatively poor properties. However, the striking advantage of using reclaimed rubbers is the cost reduction. Hence, it is important to work on establishing methods by which these reclaimed rubbers could be efficiently used and incorporated into present day products. The deterioration of properties could be minimized by blending them with varying amounts of other materials. A possibility in this direction is manufacturing of thermoplastic vulcanizates (TPVs) using reclaimed rubber and general purpose thermoplastics. In accordance with this idea, the focus of this research is to prepare DR and polypropylene (PP) based TPVs. DR is unique as the rubber itself consists of two phases- one phase consisting of uncrosslinked (including devulcanized rubber molecules), and the other phase consisting of crosslinked (un-devulcanized) rubber. These un-devulcanized crumbs act as stress concentrators because they do not break-up easily, and lead to poor physical properties. Hence, this project tries to find out ways to increase the interfacial adhesion between the rubber and PP by using reactive and non-reactive techniques. Preliminary experiments were carried out in a batch mixer to compare DR and rubber crumb (CR). DR based TPVs showed better properties than CR based TPVs, however, the properties were not useful for commercial applications. Sulphur based dynamic vulcanization was studied in a batch mixer and found to be not effective in improving the properties of DR based blends. On the other hand, DCP/ sulphur based curing system was found to show significant improvement in properties. Therefore, DCP/sulphur based curing package was studied in detail on the blends consisting of DR and PP. The optimum ratio of DCP/sulphur was found to vary depending on the ratio of DR/PP. A hypothesis regarding the mechanism of DCP/sulphur curing has been proposed, which seem to correlate well with the experimental results observed. Additionally, it was determined that DR prepared from tire rubber (DRT) performed better than DR prepared from waste EPDM (DRE) for the curing system used. Accordingly, experiments on a TSE were carried out using DRT and a combination of compatibilizing resins and curatives. This combination showed a drastic improvement in blends properties and once again the optimum ratio of compatibilizing resins seemed to depend on the ratio of DRT/PP. As a result of the work, successful strategies based on reactive compatibilization techniques were developed in order to prepare useful TPVs having up to 70% DR. A series of compatibilization techniques has been evaluated using design of experiments and various characterization techniques such as mechanical tests, scanning electron microscopy, thermal analysis and crosslink density measurements. This led to the development of a formulation, which could improve the blend properties significantly. A tensile strength of around 10 MPa and an elongation-at-break of 150-180 % could be achieved for devulcanized rubber (70%) based TPVs, which has broadened the scope for its commercial applications. In addition to that, the process was established on a TSE that has enabled a continuous and steady production of these TPVs with reasonable throughputs.

In this study, the effects of chain extension and branching on the properties of nanocomposites produced from recycled poly(ethylene terephthalate) and organically modified clay were investigated. As the chain extension/branching agent, maleic anhydride (MA) and pyromellitic dianhydride (PMDA) were used. The nanocomposites were prepared by twin-screw extrusion, followed by injection molding. Recycled poly(ethylene terephthalate), was mixed with 2, 3 and 4 weight % of organically modified montmorillonite. During the second extrusion step, 0.5, 0.75 or 1 weight % of MA or PMDA was added to the products of the first extrusion. As the second extrusion step is reactive extrusion, the anhydrides were added at three different screw speeds of 75, 150, 350 rpm, in order to observe the change of properties with the screw speed. XRD analysis showed that, the interlayer spacing of Cloisite 25A expanded from 19.21 &amp / #506 / to about 28-34 &amp / #506 / after processing with polymer indicating an intercalated structure. PMDA, MA and organoclay content as well as the screw speed did not have a recognizable effect on interlayer distance. In the first extrusion step, nanocomposites containing 3% organoclay content gave significant increase in Young&rsquo / s modulus and decrease in elongation to break values indicating good interfacial adhesion. After the addition of chain extenders, it was observed that both MA and PMDA gave rise to improved mechanical properties of the nanocomposite owing to the branching and chain extending effects that increase the molecular weight. However, PMDA gave better mechanical properties at lower content which makes it a more effective chain extender. DSC analysis showed that MA was more effective in increasing the glass transition temperature and melting temperature in comparison to PMDA.