2024-11-12 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/2024/nov/carpet-concrete
- https://www.sciencedirect.com/science/article/pii/S0950061824030630
- https://www.sciencedirect.com/science/article/pii/S235271022401595X
- https://www.sciencedirect.com/science/article/abs/pii/S0950061822034419?via%3Dihub
- https://ascelibrary.org/doi/10.1061/%28ASCE%29MT.1943-5533.0004538
- https://www.concrete.org/publications/internationalconcreteabstractsportal.aspx
多様なカーペット廃繊維の導入によるコンクリート性能と持続可能性の向上 Enhancement of concrete performance and sustainability through incorporation of diverse waste carpet fibres
Nayanatara Gamage, Chamila Gunasekara, David W. Law, Shadi Houshyar, Sujeeva Setunge, Andrzej Cwirzen
Construction and Building Materials Available online: 17 August 2024
DOI:https://doi.org/10.1016/j.conbuildmat.2024.137921
Highlights
- PTT T1 (0.5 %) had highest flexural strength, 11.8 % higher at 28 days, than control.
- Compressive strength and shrinkage reduction were optimum with 0.3 % fibre volume.
- Nylon T1 fibres (0.3 %) reduced shrinkage by 22.3 % at 90 days compared to the control.
- Nylon T1(0.3 %) had the lowest porosity, 81.12 % lower than the control at 28 days.
- Hydrophobic fibres had an ITZ of 15 µm, while hydrophilic fibres had an ITZ of 10 µm.
Abstract
Carpet fibres have demonstrated the potential to mitigate early-age cracking and improve tensile properties in concrete. However, a detailed analysis of the varied types of standard carpet fibres in reinforced concrete has been lacking. This study aims to bridge this gap by investigating the performance of concrete reinforced with widely used waste carpet fibres, namely Nylon, Polypropylene, Polytrimethylene terephthalate, and Polyester. The study employs fibres at 0.3 % and 0.5 % volume fractions with a 12 mm length. The research examines mechanical properties, shrinkage and cracking behaviour, pore structure, microstructure, and the ITZ. Results show that 0.3 % fibre volume yielded optimal performance based on GRA analysis. All fibre types reduced shrinkage compared to the control with no fibres. Nylon T1 at 0.3 % achieved a 22.3 % reduction at 90 days. Furthermore, fibre inclusion enhanced flexural and splitting tensile strengths up to 12 % and 39 % respectively due to fibre bridging, pore refinement, and reduced porosity. Notably, individual fibre mechanical properties influenced concrete performance significantly. Hydrophilic fibres exhibited a thinner 10 µm ITZ compared to 15 µm for hydrophobic fibres, contributing to denser interfacial regions and improved bonding. This study demonstrates the potential of carpet fibre-reinforced concrete as a sustainable solution, offering enhanced mechanical properties, shrinkage mitigation, and effective utilization of carpet waste, addressing critical issues in construction and waste management sectors.
現場打ち繊維補強コンクリートの早期乾燥による水分輸送解析のためのデータ強化アプローチ A data-enhanced approach for early-age drying induced moisture transport analysis on in-situ casted textile fibre reinforced concrete
Hasika Dharmasooriya, Yuguo Yu, Chamila Gunasekara, Dilan J. Robert, Sujeeva Setunge
Journal of Building Engineering Available online: 22 June 2024
DOI:https://doi.org/10.1016/j.jobe.2024.110027
Highlights
- Early-age drying of Textile Fibre Reinforced Concrete (TFRC) is investigated.
- Coupled experimental-numerical method for moisture transport analysis is proposed.
- Inverse analysis and machine learning are leveraged for accurate predictions.
- Textile fibre usage is found to significantly alter moisture diffusivity in TFRC.
- Textile fibre volume ratio is optimised for enhanced moisture loss reduction.
Abstract
With the addition of textile fibres that alters pore structure, the novel Textile Fibre Reinforced Concrete (TFRC) exhibits great potential in reducing drying shrinkage and enhancing long-term durability. To advance material design, this study aims at developing a coupled experimental-numerical framework with a data-enhanced approach to identify the essential material properties that govern the moisture transportation in TFRC. The scope of analysis covers the TFRC manufactured with various fibre types and different fibre volumes, where the time-dependent effect associated with early age is investigated. An inverse analysis framework, coupling Particle Swarm Optimisation (PSO) and extended support vector regression (XSVR), is developed and validated against experimentation by monitoring moisture distribution. Results reveals that the incorporation of textile fibres leads to a substantial reduction in the moisture diffusivity of TFRC, as opposed to conventional concrete of identical w/b and aggregate content. Notably, TFRC mixtures with 0.4 % Nylon twist and PTT600 fibres showed a 95 % reduction in moisture diffusivity compared to the conventional concrete. This discovery illustrates the capability of textile fibres, when optimally introduced, to mitigate moisture loss from cementitious materials, reducing drying shrinkage of concrete building. The proposed approach is demonstrated to be able to robustly quantify the early-age moisture transportation in TFRC, which is of potential to guide future concrete design of using textile fibre reinforcement towards controlling early-age shrinkage in building industry.
持続可能なセメント系複合材料のための混紡繊維廃棄物の再利用： 機械的および微細構造的性能 Repurposing of blended fabric waste for sustainable cement-based composite: Mechanical and microstructural performance
Nghia P. Tran, Chamila Gunasekara, David W. Law, Shadi Houshyar, Sujeeva Setunge
Construction and Building Materials Available online: 21 November 2022
DOI:https://doi.org/10.1016/j.conbuildmat.2022.129785
Highlights
- Hydrophilic fabric fibres refine the pore structure of cementitious matrices.
- Hybrid hydrophobic and hydrophilic fibres counterbalance the pore-refining effects.
- Fabric waste fibres suppress the crack propagation and mitigate the quantity of cracks.
- Hybrid fabric fibres significantly reduces the shrinkage of cementitious composites.
- Blended fabric waste fibres can improve strength properties of cement-based materials.
Abstract
In this study, the strength properties, shrinkage and microstructures of mortar incorporating blended fabric fibres were characterised via X-ray micro CT and nanoindentation. Three different hybrid recycled fabric fibres, namely Kevlar/Nomex, Kevlar/Nylon and Nomex/Nylon fibres were investigated at three different blend ratios (2:1, 1:1, and 1:2). The fibre content was maintained at 0.3 % for all mixes. The findings indicated that the optimum blend ratio for hybrid fabric fibres is 1:1. At this optimum fibre blend ratio, an enhancement by 2.7 %, 4.8 % and 5.9 % in compressive strength, together with 9.8 %, 12 % and 13.4 % in flexural strength of mortar are recorded, corresponding to the inclusion of hybrid Nomex/Nylon, Kevlar/Nomex and Kevlar/Nylon fibres respectively. Kevlar/Nomex fibres display no effect in drying shrinkage mitigation, irrespective of blend ratios. In contrast, Kevlar/Nylon and Nomex/Nylon fibres result in reducing 180-day shrinkage rates by up to 13.9 % and 11 % respectively. The hybrid fabric fibres were found to refine the pore network, especially the highly hydrophilic Kevlar/Nomex fibres. Also, an increase in curing days from 7 to 90 days densifies the microstructure near the fibre-matrix interface due to the growth of hydration products (LD/HD C
SH and CH). These research findings can open the pathway for utilising textile waste in landfill as reinforcing members for cementitious matrices toward sustainable building and construction.
セメント系複合材料におけるリサイクル繊維の利用 Utilization of Recycled Fabric-Waste Fibers in Cementitious Composite
Nghia P. Tran, Chamila Gunasekara, David W. Law, Shadi Houshyar, and Sujeeva Setunge
Journal of Building Engineering Published:Oct 25, 2022
DOI:https://doi.org/10.1061/(ASCE)MT.1943-5533.0004538
Abstract
Three types of textile fabric waste, namely Kevlar, Nomex, and Cordura Nylon, were investigated in this study. The effects of the fiber parameters: volume fraction (0.1%, 0.3%, and 0.5%), length (6, 12, and 24 mm), and use of 1D fiber (width of 0) versus 2D woven fabric fiber (width of 3 and 6 mm) on strength properties, flowability, and shrinkage were studied to determine the optimum textile parameters. The pore structure, microstructure, and fiber-matrix interfacial properties of the optimised mixtures were then characterized by means of X-ray micro-CT, SEM, and nanoindentation at 7, 28, and 90 days. Results showed that the optimized parameters for three types of fabric fibers are 1D fiber (width of 0), length of 12 mm, and volume fraction of 0.3%. This optimized design provided an enhancement of strength and shrinkage resistance. Pore refinement was pronounced in the case of hydrophilic Kevlar and Nomex fibers. However, this also correlates to inferior performance in shrinkage resistance of mortar compared to hydrophobic Cordura Nylon. The fiber-matrix ITZ thickness was dependent on fiber size, while the wettability of fibers (i.e., hydrophobicity or hydrophilicity) was observed to affect the phase distribution in the vicinity of the fiber surface. Furthermore, a large volumetric proportion of the structure is porous in nature (more than 50%) in the region of the fiber-matrix interface after 7 days. With the increment of curing age, the microstructure at the fiber interface becomes denser due to the hydration of the clinker phase facilitating the growth of CSH and CH phases.
アップサイクルポリプロピレンおよびポリトリメチレンテレフタレートカーペット廃繊維のセメント系複合材料への利用 Upcycled Polypropylene and Polytrimethylene Terephthalate Carpet Waste in Reinforcing Cementitious Composites
Nghia P. Tran, Chamila Gunasekara, David W. Law, Shadi Houshyar, and Sujeeva Setunge
ACI Materials Journal Date: 7/1/2022
DOI:10.14359/51734688
Abstract
In this study, carpet waste fibers—namely, polypropylene (PP) and polytrimethylene terephthalate (PTT) in the form of mono microfibers and hybrid combinations—were studied. The optimization of mono fiber parameters for fiber content (0.1, 0.3, and 0.5%) and length (6, 12, and 24 mm [0.236, 0.742, and 0.945 in.]) were conducted to achieve the optimum strength properties and minimize drying shrinkage. The microstructure, pore structure, and fiber-matrix interfacial properties of the optimized samples were characterized at 7, 28, and 90 days by means of scanning electron microscopy (SEM), X-ray micro-computed tomography (CT), and nanoindentation. The research data revealed that the inclusion of either the optimized mono PP fiber (υf = 0.5% and l = 12 mm [0.472 in.]) or PTT fiber (υf = 0.1% and l = 12 mm [0.472 in.]) improved the compressive strength of 4.3% and 16.1%, and the flexural strength by 11.5% and 9.2% at 28 days, respectively. Hybrid carpet fibers (0.4% PP + 0.1% PTT) provided a greater enhancement in compressive strength of 6.6%, and flexural strength by 13% at 28 days. Drying shrinkage mitigation of mortar over 120 days was recorded as 18.4, 22.3, and 25.8%, corresponding to the addition of 0.5% PP fibers, 0.1% PTT fibers, and hybrid PP/PTT carpet fibers. A pore-refining effect was also observed for mortars with 0.5% PP and hybrid PP/PTT carpet microfibers. The SEM images indicated that the trilobal cross-sectional shape of PTT carpet fibers had a stronger anchoring effect with cement hydrates than the rounded shape of PP carpet fibers. Nanoindentation identified the thickness of the fiber-matrix interfacial transition zone (ITZ) as approximately 15 μm (5.9 × 10–4 in.) for both mono PP and PTT fibers. Approximately 50% of the phases in the vicinity of the fiber-matrix interface comprised a porous structure at 7 days. However, the hydration of clinker over the 90-day period promoted the formation of calcium-silicate-hydrate (C-S-H) and portlandite to form a dense microstructure.
