2025-10-27 ロイヤルメルボルン工科大学（RMIT）
＜関連情報＞
- https://www.rmit.edu.au/news/all-news/2025/aug/roof-tiles
- https://www.sciencedirect.com/science/article/pii/S2214993725002295
- https://link.springer.com/article/10.1007/s11367-025-02443-w
- https://www.sciencedirect.com/science/article/pii/S2214509524009677
廃棄物を統合したコンクリート屋根瓦の高度な製造：TRL 6へのスケールアップ Advanced manufacturing of waste-integrated concrete roof tiles: Scaling up to TRL 6
Yulin Patrisia, Chamila Gunasekara, David W. Law, Thomas Loh, Kate Nguyen, Sujeeva Setunge, Tsz Shan So
Sustainable Materials and Technologies Available online: 25 May 2025
DOI:https://doi.org/10.1016/j.susmat.2025.e01461
Graphical abstract
Highlights
- Integration of pond ash and unwashed glass sand in roof tiles were achieved.
- Concrete roof tiles were produced and achieved a Technology Readiness Level of 6.
- Concrete roof tiles met Australian standard and all product specifications.
- Waste-integrated roof tiles was 5 % lighter than conventional tiles.
- Waste-integrated roof tiles withstand up to 600 °C fire exposure.
Abstract
This research examines the integration of pond ash and unwashed glass sand in concrete roof tiles. After successfully completing a laboratory-based trial with the optimal composition of 10 % pond ash and 10 % glass sand, a manufacturing trial was conducted in collaboration with a leading Australian roofing manufacturer to produce the concrete roof tile specimens. The optimized roof tiles met AS 2049–2002 standards for roof tiles, including transverse strength, water absorption, permeability, and salt attack. The waste-integrated concrete roof tiles were up to 5 % lighter and exhibited better performance under fire exposure compared to conventional roof tiles. Roof tiles incorporated with waste and exposed to 120 °C and 300 °C showed up to a 6 % increase in transverse strength, attributed to additional C-S-H formation. Although strength decreased at 600 °C and 800 °C under fire exposure due to thermal expansion incompatibility and a loss of bonding strength in the interfacial transition zone between the aggregates and matrix, waste-integrated roof tiles retained 11–13 % of their original strength, whereas conventional roof tiles retained only 6 % of their unexposed strength. The inclusion of pond ash increased alumina products, promoting additional Si-O-Al bonds and resulting in additional C-A-S-H formation. Pond ash also helped refine pores due to its micro filler effect and pozzolanic activity. However, incorporating more than 10 % recycled glass reduced performance, as its smooth surface weakened the bond between the cement matrix and the glass aggregates. Overall, the roof tile product explored in this study demonstrates strong potential as an eco-friendly concrete solution, offering notable advantages by mitigating the environmental impact of unwashed glass sand and pond ash. This waste-integrated concrete roof tile was successfully demonstrated in a real-world setting, achieving a Technology Readiness Level (TRL) of 6.
廃棄物統合コンクリート製品の評価：ゆりかごからゆりかごまでの視点 Assessment of waste-integrated concrete products: a cradle-to-cradle perspective
Yulin Patrisia,David W. Law,Chamila Gunasekara & Sujeeva Setunge
The International Journal of Life Cycle Assessment Published:20 March 2025
DOI:https://doi.org/10.1007/s11367-025-02443-w
Abstract
Purpose
Bricks and roof tiles are commonly employed in construction, posing environmental challenges due to their substantial use of natural resources. Efforts to mitigate these concerns include the integration of recycled materials. However, within the framework of life cycle assessment (LCA), it is imperative to ascertain that the incorporation of recycled materials enhances the sustainability of the product across its entire life cycle. This research presents a thorough cradle-to-cradle LCA of concrete bricks and roof tiles integrated with waste materials utilized in Australia housing construction compared to conventional Portland cement-based concrete products. The research also examines how the selection of allocation methods for raw materials impacts the results of the LCA during the manufacture stage of the concrete products.
Methods
This study conducts a cradle-to-cradle LCA of waste-integrated concrete bricks and roof tiles, using pond ash and unwashed recycled glass sand due to their widespread availability and proven performance. It examines three allocation methods (no allocation, mass, and economic allocation) for the initial raw waste materials for a cradle-to-gate boundary application (the allocation method is excluded from the secondary use of the recycled materials). LCA modelling is performed using SimaPro 9.3.0.3 software, with data support from Ecoinvent v.3.8 (2021) and AusLCI v.1.42 (2023) databases with system models based on the cut-off approach.
Results and discussion
The study highlights that integrating waste materials into bricks and roof tiles reduces environmental impacts across most categories compared to conventional products. The combination of pond ash and recycled glass sand can reduce GWP by 9.86% and 8.21% for roof tiles for bricks within the cradle-to-gate scenario. Mass and economic allocation contribute to slightly higher impacts, approximately 0.789–1.188% and 0.061–0.138%, respectively. Waste-integrated concrete products generally exhibit lower environmental impacts across midpoint categories compared to conventional products in the cradle-to-cradle boundary. GWP waste-integrated bricks and roof tiles are lower than those of conventional products by 8.00–8.72% and 5.51–6.35%, respectively. Moreover, among the three post-demolition scenarios, when credits for waste material substitution are not considered, recycling demolished material into recycled aggregates utilizing the standard recycling method emerges as the most environmentally advantageous approach, outperforming landfilling and recycled demolished aggregate using the advanced recycling method. However, when credits are assigned for the utilization of recycled materials, Scenario 3 demonstrates lower environmental impacts than Scenario 2, except for ODP in WCB and WCR. The production of ultrafine powders as SCMs in Scenario 3 reduces GP cement demand, further lowering the impacts and emphasizing the importance of adopting a lifecycle perspective in LCA to fully capture the benefits of recycling.
Conclusions and recommendations
Incorporating pond ash and unwashed recycled glass sand holds promise for mitigating environmental impacts. Recycling demolished concrete as recycled aggregate for concrete using standard recycling methods was found to be the best scenario at end-of-life compared with sending to landfill and using advanced recycling methods. A deliberate selection of raw materials, coupled with exploring the advantages of integrating innovative cementitious materials and substituting aggregates, is crucial for advancing an environmentally conscious recycling process. Additional research and development are vital to identify the most effective combinations for utilizing waste materials in concrete products, thereby improving sustainability without compromising performance.
池灰と未洗浄リサイクルガラス砂の統合による持続可能な構造用コンクリートレンガのエンジニアリングポテンシャルの最適化 Optimizing engineering potential in sustainable structural concrete brick utilizing pond ash and unwashed recycled glass sand integration
Yulin Patrisia, Chamila Gunasekara, David W. Law, Thomas Loh, Kate T.Q. Nguyen, Sujeeva Setunge
Case Studies in Construction Materials Available online: 5 October 2024
DOI:https://doi.org/10.1016/j.cscm.2024.e03816
Abstract
The Australian construction sector faces a dual challenge of high demand for concrete bricks and the need for sustainable materials. This research investigates eco-friendly structural concrete brick formulations, incorporating pond ash and unwashed recycled glass sand. It aims to provide scientific evidence on their engineering performance as per AS/NZS 4455.1:2008 standard, thermal insulation, and fire resistance properties. Additionally, microstructural, chemical, and pore-structure analyses are carried out to gain insights into the reaction mechanisms and the evolution of their properties. Findings indicate that bricks with 15 % pond ash and 20 % unwashed glass sand meet structural requirements with compression strength of 29.63 MPa at 28 days. Enhanced thermal insulation is observed due to the lower densities of pond ash and glass sand. After a 2-hour exposure to elevated temperatures, the unexposed surface of these bricks remains below 180°C, satisfying fire resistance criteria for wall elements. However, microstructure and chemistry analyses suggest lower compression and tensile strength comparable conventional bricks because of low reactivity of the pond ash and the smooth surface of the glass sand.
