scholarly journals Control of Cracking in Textile Reinforced Concrete with Unresin Carbon Fibers

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3209
Author(s):  
Rui Neves ◽  
Diogo Felicíssimo

Textile reinforced concrete (TRC) is an emerging construction material with interesting potential concerning sustainability, providing corrosion-free and lightweight solutions. Ordinarily, fiber bundles, impregnated with resin, are used. In this research the performance of reinforcement with unresin fibers is investigated. Control of cracking is considered the key performance factor and is assessed through tensile testing. However, economic and environmental aspects are addressed as well. Then, four different mixes/matrices were considered, without the addition of special/expensive admixtures. TRC ties were subject to direct tension tests, with load and deformation monitoring to assess the influence of mechanical reinforcement ratio on the cracking, failure and toughness of these composites, as well as of the matrix properties on the maximum load. It was observed that at a macro-level TRC behaves like conventional reinforced concrete, concerning crack control. Based on the maximum loads attained at the different composites, it was found that this particular TRC is economically viable. It is suggested that matrix workability may influence the maximum load.

2021 ◽  
Author(s):  
Sergej Rempel ◽  
Marcus Ricker ◽  
Tânia Feiri

Abstract Textile-reinforced concrete has emerged in recent years as a new and valuable construction material. The design of textile-reinforced concrete requires knowledge on the mechanical properties of different textile types as well as their reinforcing behaviour under different loading conditions. Conventional load-bearing tests tend to be complex, time-consuming, costly and can even lack consistent specifications. To mitigate such drawbacks, a standardised tensile test for fibre strands was developed aiming at characterising the material properties needed for the design of a textile-reinforced concrete component. For the sake of this study, an epoxy resin-soaked AR-glass reinforcement was considered. The standardised tensile test uses a fibre strand with 160 mm length, which shall be cut out of a textile grid. The results show that the textile reinforcement has a linear-elastic behaviour, and the ultimate tensile strength can be statistically modelled by a Gumbel distribution. Furthermore, the results indicate that the modulus of elasticity is not influenced by the length or the number of fibre strands. Therefore, the mean value from the standardised test can be used for the design purpose. These findings are essential to derive an appropriate partial safety factor for the calculation of the design values of the tensile strength and can be used to determine the failure probability of textile-reinforced concrete components.


Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2246 ◽  
Author(s):  
Hyeong-Yeol Kim ◽  
Young-Jun You ◽  
Gum-Sung Ryu ◽  
Kyung-Taek Koh ◽  
Gi-Hong Ahn ◽  
...  

This paper deals with flexural strengthening of reinforced concrete (RC) slabs with a carbon textile reinforced concrete (TRC) system. The surface coating treatment was applied to a carbon grid-type textile to increase the bond strength. Short fibers were incorporated into the matrix to mitigate the formation of shrinkage-induced cracks. The tensile properties of the TRC system were evaluated by a direct tensile test with a dumbbell-type grip method. The tensile test results indicated that the effect of the surface coating treatment of the textile on the bonding behavior of the textile within the TRC system was significant. Furthermore, the incorporation of short fibers in the matrix was effective to mitigate shrinkage-induced crack formation and to improve the tensile properties of the TRC system. Six full-scale slab specimens were strengthened with the TRC system and, subsequently, failure tested. The ultimate load-carrying capacity of the strengthened slabs was compared with that of an unstrengthened slab as well as the theoretical solutions. The failure test results indicated that the stiffness and the ultimate flexural capacity of the strengthened slab were at least 112% and 165% greater, respectively, than that of the unstrengthened slab. The test results further indicated that the strengthening effect was not linearly proportional to the amount of textile reinforcement.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sergej Rempel ◽  
Marcus Ricker ◽  
Tânia Feiri

AbstractTextile-reinforced concrete has emerged in recent years as a new and valuable construction material. The design of textile-reinforced concrete requires knowledge on the mechanical properties of different textile types as well as their reinforcing behaviour under different loading conditions. Conventional load-bearing tests tend to be complex, time-consuming, costly and can even lack consistent specifications. To mitigate such drawbacks, a standardised tensile test for fibre strands was used to characterise the material properties needed for the design of a textile-reinforced concrete member. The standardised tensile test uses a fibre strand with 160 mm length, which is cut out of a textile grid. For the sake of this study, an epoxy resin-soaked AR-glass reinforcement was considered. The results show that the textile reinforcement has a linear-elastic behaviour, and the ultimate tensile strength can be statistically modelled by a Gumbel distribution. Furthermore, the results indicate that the modulus of elasticity is not influenced by the length or the number of fibre strands. Therefore, the mean value attained from the standardised test can be used for design purposes. These findings are essential to derive an appropriate partial safety factor for the calculation of the design values of the tensile strength and can be used to determine the failure probability of textile-reinforced concrete members.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Fahed Alrshoudi

There has been a rising interest in utilising textile reinforcement such as carbon tows in constructing concrete components to enhance the performance of conventional reinforced concrete. Textile-reinforced concrete (TRC) has been used as a construction material mostly as primary reinforcement. However, the structural performance of TRC members has not been investigated in depth. Therefore, to better understand TRC beams’ behaviour under bending load, a widespread experimental investigation was conducted. The results of tensile stress-strain, load-deflection, moment-curvature, and tension stiffening behaviours of TRC beams were associated with conventional steel-reinforced concrete (SRC) beams. In this study, the four-point bending and tensile strength tests were performed. The results revealed that, unlike the stress-strain behaviour observed in steel, textile reinforcement does not exhibit yielding strain. The flexural behaviour of TRC beams shows no similarity to that of SRC beams at postcracking formation. Besides, the moment capacity and tension stiffening of TRC beams were found 56% and 7 times higher than those of SRC beams, respectively. Therefore, in light of these results, it can be said that TRC beams behaviour differs from that of SRC beams.


2021 ◽  
Vol 54 (4) ◽  
Author(s):  
Edoardo Rossi ◽  
Norbert Randl ◽  
Peter Harsányi ◽  
Tamás Mészöly

AbstractWhen producing a Textile Reinforced Concrete structure or element, joining separate textile layers might be a necessity, driven for example by the limited dimensions of commercially available fabrics. A possible way of producing such joints is by overlapping different textile sheets. Overlapped joints, however, need to be cast with particular attention since they might represents weak elements of the structure, leading to premature failure. An experimental campaign was performed, aimed at identifying the effects of a symmetric vs non-symmetric arrangement of the textile fabrics within the overlapping length and tensile characteristics of the matrix on such type of joints. Fifteen specimens, produced using a fully epoxy impregnated carbon textile fabric and an Ultra High Performance Concrete (UHPC) matrix, were tested under tension in a uniaxial setup and measurements were performed using a Digital Image Correlation system. The in-plane and out-of-plane behaviour of each specimen was studied. The results highlight the importance of producing symmetric elements as well as the beneficial effects that the admixture of short dispersed steel fibres to the cementitious matrix provide to such kind of joints


2020 ◽  
Vol 9 (2) ◽  
pp. 437 ◽  
Author(s):  
Amr G. Ghoneim ◽  
Hilal A. Hassan ◽  
Louay A. Aboul-Nour

Fibers and bacterial additives in concrete have achieved significant success as a construction material. This paper presents the field of concrete self-repairing by introducing both Bacillus subtilis bacteria and polyethylene fiber as a dual-components. The main research goal is to reveal the principles of concrete self-repairing. At first, the research investigates the fiber-reinforced-concrete behavior, the concrete self-repairing process with the Bacillus subtilis bacteria for forming bacterial-concrete. And then, the study highlights the damage-repairing numerical simulation of fiber-reinforced-bacterial-concrete. The research shows the bacterial-concrete benefits to durability and mechanical properties besides to the polyethylene fiber assistance to enhance post-cracking tensile resistance and the pre-peak elastic modulus of concrete. The novelty of the fiber-reinforced-bacterial-concrete is the matrix combined improvement of both basic material properties and the post-cracking deflection capacity.  


10.14311/654 ◽  
2004 ◽  
Vol 44 (5-6) ◽  
Author(s):  
M. Konrad ◽  
R. Chudoba

In this paper we analyze the performance of a bond layer between the multi-filament yarn and the cementitious matrix. The performance of the bond layer is a central issue in the development of textile-reinforced concrete. The changes in the microstructure during the loading result in distinguished failure mechanisms on the micro, meso and macro scales. The paper provides a brief review of these effects and describes a modeling strategy capable of reflecting the failure process. Using the model of the bond layer we illuminate the correspondence between the disorder in the microstructure of the yarn and the bonding behavior at the meso- and macro level. Particular interest is paid to the influence of irregularities in the micro-structure (relative differences in filament lengths, varying bond quality, bond-free length) for different levels of local bond quality between the filament surface and the matrix. 


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