Static behaviour of high-volume landfill waste filled composite railway sleepers

Static behaviour of high-volume landfill waste filled composite railway sleepers

The Australian railway industry has the sixth largest permanent railway track in the world. Every year the railway industry requires millions of railway sleepers. The traditional railway sleepers predominantly are made of timber, steel and concrete. These current sleeper materials have performance and environmental limitations regarding recycling, durability, and carbon emissions throughout their life cycle. In order to find a sustainable sleeper material, research studies have been conducted on composites as it has many advantages including high strength-to-weight ratio, excellent resistance against corrosion, moisture, and insects, thermal and electrical resistance, and environmental friendliness. The recent development of recycled plastic sleeper offers good environmental sustainability, but their strength and stiffness are significantly lower than traditional timber sleepers. On the other hand, some companies have developed fibre based composite sleepers and they are performing very similar to timber sleepers, but 5 to 10 times more expensive than traditional timber sleepers. Therefore, an alternative material to design for the development of railway sleeper is essential at this stage. In this research, an attempt has been made to develop an alternative materials railway sleeper that can replace traditional timber with an added advantage of environmental sustainability. To achieve this, a concept of composite railway sleeper consisting of high-performance Glass Fibre Reinforced Polymer (GFRP) and low-cost waste materials such as waste-based composite woods and recycled plastic panels is investigated. This study examines the bond behaviour of GFRP profiles, composite wood and plastic panels with cement grouts that have varying grout materials and surface treatments. A variety of composite sleeper combinations are tested under the three-point bending to determine their load carrying capacity and failure behaviour. Based on the findings of this study, it appears that surface coating of GFRP profiles with epoxy resin mixed with glass sand can improve the bonding performance significantly. Cement grout can be a suitable material for bonding composite woods and plastic panels when used as an infill material for hollow GFRP tubes. While the exterior GFRP profile of the composite sleeper dominates its behaviour, the interior infill material helps maximise load carrying capacity and protect against premature failure of the profile. The strength and stiffness obtained from the proposed concept of railway sleeper concept indicate that it can meet basic structural performance requirements.

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