Sustainable engineered geopolymer composites incorporating recycled waste rubber as full replacement of fine aggregates
Recycled waste rubber from end-of-life tyres offers a sustainable alternative to natural aggregates in construction materials. Most existing studies have however typically limited the rubber replacement ratios to below 30 % (by volume) due to the associated strength reduction. This study addresses t...
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Elsevier
2025-07-01
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| Series: | Journal of Materials Research and Technology |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785425018113 |
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| author | Feihong Wan Yutao Guo Miaozi Zheng Binbin Li Ahmed Y. Elghazouli |
| author_facet | Feihong Wan Yutao Guo Miaozi Zheng Binbin Li Ahmed Y. Elghazouli |
| author_sort | Feihong Wan |
| collection | DOAJ |
| description | Recycled waste rubber from end-of-life tyres offers a sustainable alternative to natural aggregates in construction materials. Most existing studies have however typically limited the rubber replacement ratios to below 30 % (by volume) due to the associated strength reduction. This study addresses this limitation by developing rubberised engineered geopolymer composites (RU-EGCs) in which fine silica sand (FSS) is replaced by high volume of rubber (0 %, 30 %, 60 %, and 100 %), aiming to simultaneously improve ductility and sustainability. A detailed experimental evaluation is conducted in this study through mechanical testing, microstructural characterisation, and life cycle assessment (LCA), for understanding the fundamental performance of RU-EGCs. The results show that increasing the rubber replacement ratio reduces the compressive strength yet markedly improves the ductility and crack control. The fully rubberised mixture is shown to achieve a tensile strain of 7.7 % and maintains a compressive strength of 47 MPa. X-ray computed tomography (X-CT) and backscattered electron (BSE) imaging analyses also reveal increased porosity and a wider interfacial transition zone (ITZ) with rubber incorporation, which facilitate early crack initiation. Nevertheless, strong fibre/matrix bonding ensures sufficient bridging stress and energy dissipation, hence promoting a transition toward high ductility. Moreover, the LCA results demonstrate notable environmental benefits whereby, compared to typical engineered cementitious composites (ECC), the developed RU-EGCs achieves more than 40 % reduction in both embodied carbon and material cost. Overall, the findings of this investigation lays down an approach for designing sustainable ultra-high-ductility EGC through high-volume rubber utilisation, offering strong potential for practical application. |
| format | Article |
| id | doaj-art-68c3c1db5fc94735939ea12601af28a0 |
| institution | Kabale University |
| issn | 2238-7854 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Materials Research and Technology |
| spelling | doaj-art-68c3c1db5fc94735939ea12601af28a02025-08-20T03:35:40ZengElsevierJournal of Materials Research and Technology2238-78542025-07-01375614564110.1016/j.jmrt.2025.07.153Sustainable engineered geopolymer composites incorporating recycled waste rubber as full replacement of fine aggregatesFeihong Wan0Yutao Guo1Miaozi Zheng2Binbin Li3Ahmed Y. Elghazouli4Shenzhen International Graduate School, Tsinghua University, Shenzhen, ChinaShenzhen International Graduate School, Tsinghua University, Shenzhen, China; Corresponding author.State Key Laboratory of Hydroscience and Engineering, Department of Hydraulic Engineering, Tsinghua University, Beijing, ChinaShenzhen International Graduate School, Tsinghua University, Shenzhen, China; State Key Laboratory of Hydroscience and Engineering, Department of Hydraulic Engineering, Tsinghua University, Beijing, ChinaDepartment of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China; Department of Civil and Environmental Engineering, Imperial College London, UKRecycled waste rubber from end-of-life tyres offers a sustainable alternative to natural aggregates in construction materials. Most existing studies have however typically limited the rubber replacement ratios to below 30 % (by volume) due to the associated strength reduction. This study addresses this limitation by developing rubberised engineered geopolymer composites (RU-EGCs) in which fine silica sand (FSS) is replaced by high volume of rubber (0 %, 30 %, 60 %, and 100 %), aiming to simultaneously improve ductility and sustainability. A detailed experimental evaluation is conducted in this study through mechanical testing, microstructural characterisation, and life cycle assessment (LCA), for understanding the fundamental performance of RU-EGCs. The results show that increasing the rubber replacement ratio reduces the compressive strength yet markedly improves the ductility and crack control. The fully rubberised mixture is shown to achieve a tensile strain of 7.7 % and maintains a compressive strength of 47 MPa. X-ray computed tomography (X-CT) and backscattered electron (BSE) imaging analyses also reveal increased porosity and a wider interfacial transition zone (ITZ) with rubber incorporation, which facilitate early crack initiation. Nevertheless, strong fibre/matrix bonding ensures sufficient bridging stress and energy dissipation, hence promoting a transition toward high ductility. Moreover, the LCA results demonstrate notable environmental benefits whereby, compared to typical engineered cementitious composites (ECC), the developed RU-EGCs achieves more than 40 % reduction in both embodied carbon and material cost. Overall, the findings of this investigation lays down an approach for designing sustainable ultra-high-ductility EGC through high-volume rubber utilisation, offering strong potential for practical application.http://www.sciencedirect.com/science/article/pii/S2238785425018113Engineered geopolymer composites (EGC)Recycling waste rubberMechanical propertiesDuctilitySustainability |
| spellingShingle | Feihong Wan Yutao Guo Miaozi Zheng Binbin Li Ahmed Y. Elghazouli Sustainable engineered geopolymer composites incorporating recycled waste rubber as full replacement of fine aggregates Journal of Materials Research and Technology Engineered geopolymer composites (EGC) Recycling waste rubber Mechanical properties Ductility Sustainability |
| title | Sustainable engineered geopolymer composites incorporating recycled waste rubber as full replacement of fine aggregates |
| title_full | Sustainable engineered geopolymer composites incorporating recycled waste rubber as full replacement of fine aggregates |
| title_fullStr | Sustainable engineered geopolymer composites incorporating recycled waste rubber as full replacement of fine aggregates |
| title_full_unstemmed | Sustainable engineered geopolymer composites incorporating recycled waste rubber as full replacement of fine aggregates |
| title_short | Sustainable engineered geopolymer composites incorporating recycled waste rubber as full replacement of fine aggregates |
| title_sort | sustainable engineered geopolymer composites incorporating recycled waste rubber as full replacement of fine aggregates |
| topic | Engineered geopolymer composites (EGC) Recycling waste rubber Mechanical properties Ductility Sustainability |
| url | http://www.sciencedirect.com/science/article/pii/S2238785425018113 |
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