Silica coating for interphase bond enhancement of carbon and AR-glass Textile Reinforced Mortar (TRM) (original) (raw)
Related papers
Journal of Composite Materials, 2019
The mechanical performance of a silica-based mineral nano-coating applied to alkali-resistant glass textile-reinforced composite materials aimed at structural strengthening is investigated experimentally. The silica nano-film is directly applied to the alkali-resistant glass fabric by sol-gel deposition. Two lime mortars are adopted as embedding matrix, which differ by the ultimate compressive strength and elongation. Uni-axial tensile tests of prismatic coupons are carried out according to the ICC AC434 guidelines. Remarkable strength and ductility enhancements could be observed in the silica-coated group, as compared to the uncoated group, for both mortar types. Digital image correlation, electron scanning and optical microscopy provide evidence of improved interphase strength. X-ray diffraction of the anhydrous mortars brings out the role of the mineralogical composition of the embedding media on the overall bonding properties of the composites. Consideration of design limits and energy dissipation capabilities reveals the crucial role of matrix ductility in bringing the contribution of interphase enhancement to full effect. We conclude that best performance requires optimizing the pairing between fabric-to-matrix adhesion and matrix ductility.
Lime-cement textile reinforced mortar (TRM) with modified interphase
Journal of Applied Biomaterials & Functional Materials, 2019
Background: Lack of interphase compatibility between the fabric and the matrix significantly impairs the load-bearing capacity of textile reinforced mortar (TRM). In this study, we consider the application of two inorganic surface coatings for enhancing the interphase bond properties. Methods: Either of two silica-based coatings, namely nano-and micro-silica, were applied to alkali-resistant glass (ARG) and to hybrid carbon-ARG woven fabric. Mechanical performance of TRM reinforced with the uncoated and the coated fabric was compared in uniaxial tensile tests. Results: Mechanical testing provides evidence of a remarkable enhancement in terms of ultimate strength and deformability for the coated specimens. This effect can be ascribed to the improved hydrophilicity of the fibers' surface and to the activation of pozzolanic reaction at the interphase. In addition, penetration of nano-and microparticles in the bundle of the textile yarns reduces the occurrence of telescopic failure.
Improving the bond behavior of textile reinforcement and mortar through surface modification
2015
The bond between mortar and textile reinforcement is of crucial evidence for Textile Reinforced Concrete (TRC). Often, SBR (Styrene-Butadiene Rubber) and EP (Epoxy) impregnated carbon and AR-Glass fibre textiles are used. However, the bonding behavior within these reinforcements for TRC has shown potential for improvement, especially when testing the adhesive tensile strength. Therefore, a preliminary trial was undertaken to investigate the influence of a surface coating with EP and sand as a bonding agent to improve the bond characteristics of TRC. A SBR-impregnated carbon textile was modified with silica sand EP ratios of 0.10, 0.20 and 0.30. In the conducted studies tensile tests on single rovings and on rectangular TRC samples have been carried out. No reduction of the tensile strength of the single rovings was reported. The first results of this study on TRC specimens with a surface modified textile reinforcement and a sand EP ratio of 0.10 already indicate an improvement of th...
Textile-to-mortar bond behaviour in lime-based textile reinforced mortars
Construction and Building Materials, 2019
Lime-based textile-reinforced mortars (TRM) have recently found a growing interest for repair and strengthening of masonry and historical structures. Despite extensive experimental and numerical investigations performed in the last years on the performance of these composites, there is still a lack of fundamental understanding of the fabric-to-mortar bond behaviour (as one of the main mechanisms affecting the cracking and nonlinear response of these composites) and the parameters affecting that. This paper, aimed at addressing this gap, presents a comprehensive experimental and analytical investigation on how the test setup, embedded length, load rate, mortar age and fabric configuration affect the bond behaviour in lime-based TRMs. In total 160 pull-out tests are performed on a glass-based and a steel-based TRM commonly used for strengthening of masonry structures. The results contribute to standardization of the test procedures for characterization of the fabric-to-mortar bond behaviour, to fundamental understanding of this mechanism and to optimization of the design of these composites for enhancing their mechanical response.
Bond behaviour in lime-based textile reinforced mortars
CRC Press eBooks, 2020
Application of textile-reinforced mortar (TRM) composites have for strengthening of existing structures or for production of new thin structural elements has attracted a growing recent attention. TRMs are made of continuous fibres (in the form of fabric or mesh) embedded in an inorganic matrix forming a composite material. The large variety of available fabric (glass, steel, basalt, PBO, etc.) and mortar types (cement-based, lime-based, etc.) leads to a wide range of mechanical properties making these composites suit able for fit-for-purpose design applications. Due to mechanical and hygrothermal compatibility issues, limebased TRMs are the preferred choice for application to existing masonry and historical structures. Meanwhile, cement-based TRMs are usually employed for application to existing concrete or new masonry structures. The main characteristic behaviour of these composites is the tension stiffening response and distributed crack ing under tensile loads which are highly influenced by the fabric-to-mortar bond behaviour. Fundamental understanding of this mechanism (the fabric-to-mortar bond behaviour) and parameters affecting that are therefore of critical importance of designing TRM composites with desired properties. This paper presents and overview of the recent studies we performed during the lat years for better udnertanding this mechanism.
Effect of Mortar Age on the Textile-to-Mortar Bond Behavior
XV International Conference on Durability of Building Materials and Components. eBook of Proceedings, 2020
Textile-reinforced mortar (TRM) composites have received extensive attention as a sustainable solution for seismic strengthening of masonry and historical structures. This new system is composed of textile fibers embedded in an inorganic matrix and is applied on the masonry and the concrete substrate surface as an externally bonded reinforcement (EBR) system. The bond at the textile-to-mortar interfaces is the main stress-transfer mechanism and, therefore, should be thoroughly investigated. Furthermore, the effectiveness of TRMs in improving the seismic performance of existing structures is highly dependent on the durability of its components, materials, textile-to-mortar bond, and their long-term behavior. Due to the novelty of these materials in application to masonry structures, several aspects related to the durability and long-term performance of them are still not clear. To that end, a new study has been launched that looks at the time effect on the mechanical properties and bond behavior between fiber and mortar. For this purpose, two different hydraulic lime-based mortars, as well as steel and glass fibers, are used to investigate the effect of mortar age on the TRM system after 180 days. The results show that at the early age of mortars, their mechanical properties, and the bond behavior of textile-to-mortar have been increased. Another critical point to remember is that by increasing the mortar age, textile-to-mortar bond and mortar strength are decreased.
New Composite Material for Masonry Repair: Mortar Formulations and Experimental Studies
Materials, 2021
The need for retrofitting existing masonry structures is progressively becoming more important due to their continuous deterioration or need to meet the current design requirements of Eurocodes. Textile-Reinforced Mortar (TRM) composite systems have emerged as a sustainable repair methodology suitable for structure retrofitting. Nevertheless, their mechanical performance is still far from being fully investigated. This paper presents an experimental study on the tensile and bond behaviors of a new mortar-based composite consisting of mineral additives, blended cement mortar, and stainless-steel grid. Three different mineral additives (silica fume, fly ash, and blast furnace slag), in binary and ternary systems were used. The experimental study included uniaxial tensile coupon testing on composite specimens and bond tests on composite material applied to clay-brick substrate. The results obtained with the different textile-reinforced cement-based mortars were compared and are discuss...
Materials and Structures, 2021
The structural effectiveness of textile reinforced mortar (TRM) composites relies on their load transfer capacity to the substrate and the interaction between textile and mortar. The bond plays a crucial role in mechanism of TRM composites. Despite some recent investigations, a deep understanding still needs to be gained on the textile-to-mortar bond to develop suitable analytical and numerical predictive models, improve test methods, and orient design criteria. This work describes a laboratory study in which pull-out tests were carried out to investigate the effect of the slip rate and cyclic loading on the textile-to-mortar bond behaviour. Alkali-resistant glass fabric and sgalvanised ultra-high tensile strength steel cords embedded in two different lime-based mortars were tested. The pull-out response was sensitive to the strain rate at low rates. Cyclic loading produced a strength degradation, which reduced with the number of cycles.
Freeze-thaw durability of glass textile-reinforced mortar composites
CRC Press eBooks, 2020
Application of textile-reinforced mortars (TRMs) for externally bonded reinforcement of existing masonry structures has received a considerable recent attention. The mechanical behaviour of these composites, which are composed of continuous fibers embedded in an organic matrix, and their effectiveness in improving the performance of strengthened structures are highly dependent on the fiber-to-mortar bond behaviour as well as the bond between TRM system and substrate. Understanding the long-term performance of these mechanisms is therefore of critical importance for design of durable TRM composites and ensuring the safety of strengthened structures. To address this aspect, the effect of freeze-thaw cycles on the textile-to-mortar bond behaviour is experimentally investigated and discussed in this paper. The results illustrate a significant deterioration of the textile-to-mortar bond performance in the studied composites.