scholarly journals RC members with a flexural‐strengthening layer of CFRP textile‐reinforced concrete under monotonic and cyclic long‐term loading

2022 ◽  
Author(s):  
Redouan El Ghadioui ◽  
Juliane Wagner ◽  
Jonas Klein ◽  
Tilo Proske ◽  
Manfred Curbach ◽  
...  
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.


2019 ◽  
Vol 9 (7) ◽  
pp. 1322 ◽  
Author(s):  
Silke Scheerer ◽  
Robert Zobel ◽  
Egbert Müller ◽  
Tilo Senckpiel-Peters ◽  
Angela Schmidt ◽  
...  

Today, the need for structural strengthening is more important than ever. Flexural strengthening with textile reinforced concrete (TRC) is a recommendable addition to already proven methods. In order to use this strengthening method in construction practice, a design model is required. This article gives a brief overview of the basic behavior of reinforced concrete slabs strengthened with TRC in bending tests as already observed by various researchers. Based on this, a design model was developed, which is presented in the main part of the paper. In addition to the model, its assumptions and limits are discussed. The paper is supplemented by selected application examples to show the possibilities of the described strengthening method. Finally, the article will give an outlook on open questions and current research.


Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3856
Author(s):  
Young-Jun You ◽  
Hyeong-Yeol Kim ◽  
Gum-Sung Ryu ◽  
Kyung-Taek Koh ◽  
Gi-Hong Ahn ◽  
...  

Textile reinforced concrete (TRC) has widely been used for strengthening work for deteriorated reinforced concrete (RC) structures. The structural strengthening often requires accelerated construction with the aid of precast or prefabricated elements. This study presents an innovative method to strengthen an RC slab-type element in flexure using a precast panel made of carbon TRC. A total of five RC slabs were fabricated to examine the flexural strengthening effect. Two of them were strengthened with the precast panel and grouting material and another set of two slabs was additionally strengthened by tensile steel reinforcement. The full-scale slab specimens were tested by a three-point bending test and the test results were compared with the theoretical solutions. The results revealed that the ultimate load of the specimens strengthened with the TRC panel increased by at least 1.5 times compared to that of the unstrengthened specimen. The application of the precast TRC panel and grouting material for the strengthening of a prototype RC structure verified its outstanding constructability.


Bauingenieur ◽  
2017 ◽  
Vol 92 (09) ◽  
pp. 364-369
Author(s):  
Sergej Rempel ◽  
Arne Spelter ◽  
Josef Hegger ◽  
Norbert Will

Zur Sicherstellung der Tragfähigkeit innerhalb der Lebensdauer von Bauteilen sind neben der Bemessung für Kurzzeitbelastungen auch ausreichende Kenntnisse zum Dauerstandverhalten erforderlich. Dies gilt insbesondere auch für den Textilbeton, der im Vergleich zu Stahlbeton eine deutlich längere Lebensdauer aufweisen soll. Das Dauerstandverhalten wird in der Regel durch die Dauerstandfestigkeit der verwendeten Werkstoffe charakterisiert, die unter anderem durch die Spannung, die Temperatur, die Feuchtigkeit und den pH-Wert (Alkalität) beeinflusst wird. Zur Untersuchung des Dauerstandverhaltens von textilbewehrtem Beton existieren zum aktuellen Zeitpunkt keine Prüfnormen. Im ersten Teil des Beitrags wird auf der Basis vorhandener Regelwerke und Prüfkonzepte für FVK-Bewehrungen, zu denen Untersuchungen zum Kriechverhalten, zur Alkaliresistenz und Dauerstandfestigkeit existieren, ein Prüfkonzept für den Textilbeton abgeleitet. Damit wird im zweiten Teil ein Versuchsaufbau vorgestellt und ein Vorschlag zum erforderlichen Prüfumfang zur Ermittlung der Dauerstandfestigkeit von Textilbeton gemacht. Mit den Ergebnissen soll die innerhalb der geplanten Nutzungsdauer eines Bauteils ansetzbare Textilspannung festgelegt werden.


2017 ◽  
Vol 36 (23) ◽  
pp. 1712-1726 ◽  
Author(s):  
Dejun Liu ◽  
Hongwei Huang ◽  
Jianping Zuo ◽  
Kang Duan ◽  
Yadong Xue ◽  
...  

For the eccentric compression structures which cannot be strengthened by wrap method, this paper presents an experimental and numerical study on flexural strengthening by applying textile reinforced concrete at the tensile face. Seven short columns were constructed and tested under eccentric load. One of the columns did not receive any strengthening and was used as the control column, whereas the rest six were externally upgraded by textile-reinforced concrete layers. The main parameters taken into account covered: (a) type of mortar, (b) preload level, and (c) number of textile-reinforced concrete layers. Besides the experimental program, a numerical investigation utilizing non-linear finite element analysis was carried out and a good agreement was obtained between the experimental and numerical results. Further, the numerical analysis was extended to additional cases to deepen the understanding of flexural-enhancing mechanism . It is concluded that textile-reinforced concrete substantially increases the flexural capacity of the eccentric compression columns; the more the textile layer, the greater the gain. However, the preload has an apparently adverse influence on the strengthening effectiveness, as it causes the strain loss of the textile; the bigger the preload level, the more the loss.


2021 ◽  
Vol 11 (6) ◽  
pp. 2771
Author(s):  
Mohammad Alma’aitah ◽  
Bahman Ghiassi ◽  
Ali Dalalbashi

This paper aims to provide a review of the current literature on the durability of textile-reinforced concrete and mortar (TRC/TRM) composites. Most previous studies have focused on the role of chemical attacks, freeze-thaw conditions, and high temperatures on the mechanical performance of these composites. Information on the long-term performance of TRCs under synergistic action of mechanical and environmental loads is scarce. Considering the variety of fabrics and matrices used for the production of TRC composites, the existing data are still very limited and comprehensive studies are needed in this field. Additionally, due to the lack of standard procedures, different approaches are often followed for durability or post-ageing mechanical tests, or sufficient data on the curing and post-ageing preparation procedures followed are not provided. These have led to incompatibility of the existing data and in some cases contradictory results on the durability of these materials.


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

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5787
Author(s):  
Hana Žáková ◽  
Jiří Pazderka ◽  
Pavel Reiterman

The main aim of this study was to investigate the improved autogenous healing of concrete caused by a crystalline admixture in combination with textile reinforced concrete (TRC). This phenomenon (improved healing) has not yet been described by any independent study, and not at all in relation to TRC. The results of the study confirmed that the interaction between TRC and the crystalline admixture’s self-healing ability is advantageous and usable. The application of crystalline admixture could ensure the long-term entirety of the TCR element, where microcracks could occur. This allows for the creation of advantageous, thin (achieved by TRC) and waterproof (achieved by the crystalline admixtures) concrete structures. Moreover, this does not depend on temperature in the range of 4–30 °C (lower temperatures are of course problematic, as for most other cementitious materials). However, the interaction of both materials has its limits; the cracks must not be too wide (max. 0.1 mm), otherwise they will not heal. On the other hand, the advantage is that it does not matter what type of cement is used (CEM I and CEM II showed the same results), and the composition of the newly formed crystals in the cracks corresponds to the composition of the C-S-H gel, so it can be assumed that secondary hydration of the Portland cement occurred in the crack area.


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