Comparative low-velocity impact response of textile-reinforced concrete and steel-fiber-reinforced concrete beams

Yoo, Doo-Yeol,Gohil, Udityasinh,Gries, Thomas,Yoon, Young-Soo SAGE Publications 2016 Journal of composite materials Vol.50 No.17

<P>In this study, the effect of the textile reinforcement type on the flexural response of textile-reinforced concrete beams under static and impact loads was investigated. In addition, to compare the flexural capacities with those of conventional steel-fiber-reinforced concrete, steel-fiber-reinforced concrete beams having similar compressive strength with that of textile-reinforced concrete were fabricated and tested according to the fiber content. Enhancements in the flexural capacities were obtained using polymer-coated textile reinforcement, and three-dimensional textile reinforcement resulted in slightly better flexural performance than two-dimensional textile reinforcement under both static and impact loads. Upon comparison with the results obtained from the steel-fiber-reinforced concrete beams, the textile-reinforced concrete specimen with polymer-coated textile reinforcement exhibited the best flexural performance in terms of the strength, toughness, and residual load carrying capacity (higher than or at least similar to those of the steel-fiber-reinforced concrete with a fiber volume content of 2%), whereas the textile-reinforced concrete specimens with uncoated textile reinforcement exhibited lower strength and toughness than those of the steel-fiber-reinforced concrete with a fiber volume content of 0.5%. Finally, the strain-rate sensitivity of the flexural strength for textile-reinforced concrete was found to be similar to that for steel-fiber-reinforced concrete.</P>

탄소 직물 배치위치에 따른 TRC 패널의 휨성능 평가

이종억,양준모,김승직,장준호 한국복합신소재구조학회 2019 복합신소재구조학회논문집 Vol.10 No.6

Textile reinforced concrete (TRC), which has merits of light weight design, free molding, and pseudo-ductile performance, is expected as a substitute for reinforced concrete. In this study, TRC panel specimens were fabricated and four-point bending tests were performed in order to investigate the flexural performance of carbon textile reinforced concrete panel and to investigate the effect of carbon textile position. In addition, the flexural behavior of the specimens was numerically calculated based on the general reinforced concrete concept and compared with the experimental results. As a result of the test, the bond failure between concrete matrix and carbon fabric resulted in a large decrease in flexural strength and the decreased performance could be reduced by the eccentric placement of the carbon fabric near the bottom. The numerical calculation results of the TRC panel showed that the initial behavior was similar to that of the bending test. However, since the occurrence of the second crack, there was a big difference between the behaviors due to bond failure. 경량화 설계 및 자유로운 성형이 가능하고 유사연성의 장점을 가지는 직물보강 콘크리트는 철근콘크리트의 대체재로큰 기대를 모으고 있다. 본 연구에서는 탄소 직물을 보강한 콘크리트 복합체 (TRC) 패널의 휨 특성을 살펴보고, 탄소 직물의배치 위치 변수에 따른 차이를 살펴보기 위해 TRC 시험체를 제작하고 4점 재하 휨실험을 수행하였다. 또한, 일반 철근콘크리트개념을 바탕으로 시험체의 휨 거동을 수치계산 결과와 실험결과를 비교하였다. 실험 결과, 콘크리트 매트릭스에서 탄소 직물간의 부착파괴로 인해 TRC 패널의 큰 휨강도 감소와 내하력 감소가 나타났고, 탄소 직물을 시험체 하부로 편심 배치한 경우 휨성능의 감소를 다소 줄일 수 있었다. TRC 패널의 수치계산 결과, 초기 거동에서는 휨실험 결과와 유사한 거동을 나타내었지만, 두 번째 균열의 발생 이후부터는 부착파괴의 발생으로 거동의 큰 차이를 나타내었다.

직물섬유 보강 콘크리트 복합패널의 휨성능에 대한 해석적 평가

양준모,손홍준,김승직,김대진 한국복합신소재구조학회 2019 복합신소재구조학회논문집 Vol.10 No.6

Textile-reinforced concrete (TRC) is a composite material, in which concrete matrix is reinforced with textile fabric, and retains high strength and excellent ductility. This paper evaluates the effective material properties of TRC members and predict their structural behavior by multiscale-based finite element simulations. For this purpose, we utilize the three-dimentional multiscale finite element method based on the reduced-order model. The load-displacement curves of several four-point bending specimens are obtained by performing a finite element analysis utilizing the obtained effective material properties and compared with the test data to verify the effectiveness of the proposed approach. 직물섬유 보강 콘크리트(textile reinforced concrete, TRC)는 콘크리트 매트릭스를 직물섬유로 보강한 복합재료로 높은강도 및 우수한 연성을 발휘한다. 본 논문에서는 TRC로 보강된 구조 부재의 성능 평가를 위해 그 유효물성치를 멀티스케일에기반한 해석적 방법을 통해 평가하였다. 유효물성치 산정을 위해 감소차수모델(reduced order model)에 기반한 3차원 유닛셀 유한요소해석법을 이용하였다. 계산된 유효물성치를 TRC 보강 휨 부재의 유한요소해석에 활용하여 하중-변위 그래프를 도출하였다. 계산된 유효물성치를 TRC 보강 휨 부재의 유한요소해석에 활용하여 하중-변위 그래프를 도출하였으며, 이의 정확성을 평가하기 위해 TRC 복합패널의 4점 휨실험을 수행하고 그 결과를 유한요소 해석결과와 비교 및 분석하였다.

접착 방식 그리드 타입 CFRP로 인장보강된 직물복합구조 인장실험체의 모르타르 압축강도에 따른 인장거동 평가

김경민,박성우 대한건축학회지회연합회 2022 대한건축학회연합논문집 Vol.24 No.6

This paper aims to experimentally evaluate the effect of the compressive strength of mortar on the tensile behavior of textile reinforced concrete (TRC) specimens applied the developed grid-type carbon fiber reinforced polymer (CFRP) reinforcement (hereafter referred to as carbon grid), K-Carbon as reinforcement. The experimental results showed that the higher compressive strength of mortar could be effective for the tensile behavior of a TRC specimen reinforced with carbon grid in terms of crack formation and strength. The tensile performance of carbon grid was also revealed to be increased with increasing compressive strength of mortar, but the tensile strength of all carbon grids placed on the specimens was less than 0.5 times the tensile strength of the carbon grids because of the local stress concentration acting on the carbon grids and the silp with mortar. On the other hand, the tensile stress-strain relationship of TRC specimens was idealized as a simple bilinear curve with a bend-over point corresponding to the initial cracking point, and the idealized bilinear curve was revealed to generally illustrate the tensile stress-strain relationship of TRC specimens.

TRM으로 보강된 RC 슬래브의 휨 성능에 관한 실험적 연구

정규산,한상훈,홍기남,고원준,조용인 한국복합신소재구조학회 2016 복합신소재구조학회논문집 Vol.7 No.4

Flexural capacity of a Textile Reinforced Mortar(TRM) was investigated by an experimental study. The test program was accomplished on reinforced concrete(RC) slabs consisted of concrete(average compressive strength of 22.23 MPa) and rebar(strength class of SD400). RC slab had 450 mm and 150 mm in size and 2,600 mm in clear span. Strengthening was accomplished by applying carbon-fiber mesh in layers of mortar. Control slab(unstrengthened) and six slabs strengthened with TRM were fabricated to confirm the reinforcing performance in this study. Test variables considered amount of reinforcement and use of anchorage. As a results, it was validated that the flexural capacity of slabs strengthened with TRM increased from 159.9% to 285.2% according to the amount of TRM compared with unstrengthened slab. Experimental results indicated that there are increase in ductility as well as load carrying and deformation capacities when using multiple layers of textile.

Effect of polymer addition on air void content of fine grained concretes used in TRCC

Esma Gizem Daskiran,Mehmet Mustafa Daskiran,Mustafa Gencoglu 사단법인 한국계산역학회 2017 Computers and Concrete, An International Journal Vol.20 No.2

Textile Reinforced Cementitious Composite (TRCC) became the most common construction material lately and have excellent properties. TRCC can be employed in the manufacture of thin-walled facade elements, load-bearing integrated formwork, tunnel linings or in the strengthening of existing structures. These composite materials are a combination of matrix and textile materials. There isn\'t much research done about the usage of polymer modified matrices in textile reinforced cementitious composites. In this study, matrix materials named as fine grained concretes (dmax 1.0 mm) were investigated. Air entraining effect of polymer modifiers were analyzed and air void content of fine grained concretes were identified with different methods. Aim of this research is to study the effect of polymer modification on the air content of fine grained concretes and the role of defoamer in controlling it. Polymer modifiers caused excessive air entrainment in all mixtures and defoamer material successfully lowered down the air content in all mixtures. Latex polymer modified mixtures had higher air content than redispersible powder modified ones. Air void analysis test was performed on selected mixtures. Air void parameters were compared with the values taken from air content meter. Close results were obtained with tests and air void analysis test found to be useful and applicable to fine grained concretes. Air void content in polymer modified matrix material used in TRCC found significant because of affecting mechanical and permeability parameters directly.

Dynamic Compressive Behavior of CTRC and ECC Layered Concrete under Impact Load

Aofei Guo,Fen Zhou,Yunxing Du,Rui Yan 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.11

In this study, carbon textile reinforced concrete (CTRC) and engineered cementitious composites (ECC), together with steel fibers, were combined to fabricate two-layer concrete, called CTRC-ECC concrete. The dynamic compressive behavior of CTRC-ECC concrete was studied through the quasi-static compressive test and the impact test using a split Hopkinson pressure bar (SHPB). The effects of the thickness of CTRC, steel fibers, and impact face on the dynamic compressive strength, dynamic increase factor (DIF), strain at peak, and impact toughness of CTRC-ECC concrete were discussed. The results showed that as the thickness of CTRC increased, the dynamic compressive strength followed an increasing trend generally; the DIF decreased; and the strain at peak and the impact toughness increased firstly and then decreased. The addition of steel fibers to CTRC could increase the dynamic compressive strength significantly when the thickness of CTRC is less than 10 mm, improve the impact toughness slightly, but reduce the DIF significantly. In terms of the strain at peak, it firstly increased and then reduced and lastly did not change too much by steel fibers. The effect of impact face on the dynamic compressive strength, DIF, and impact toughness was not significant; however, when the CTRC face was subjected to impact load, the strain at peak could be slightly higher.

Flexural Durability and Chloride Diffusion Equation of TRC-Strengthened Beams under a Chloride Environment

Shiping Yin,Yuntao Hua,Yulin Yu 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.6

In this study, the chloride ion diffusion and structural performance of beams reinforced with textile-reinforced concrete (TRC) were evaluated. The parameters investigated were chloride concentration, sustained load and number of textile layers. The results demonstrate that the content and diffusion coefficient of chloride increased with increasing chloride concentration. Higher chloride concentrations accelerated the crack propagation and deflection changes and caused the reduction of the load-carrying capacity of the beams. The sustained load promoted the chloride transport of the TRC, increasing the chloride ion content and diffusion coefficient and causing substantial damage to the microstructure of the TRC. In addition, the performance (such as cracking resistance, deflection and flexural capacity) of beams with a large sustained load ratio decreased to a less extent than did the performance of the unloaded beams. The content and diffusion coefficient of chloride in the unstrengthened beams were obviously larger than those in the strengthened beams, but increasing the textile layers number had little influence on these factors. In addition, for the unstrengthened beams, the cracks and deflections developed rapidly, and the load decreased greatly, especially the cracking load. Finally, in accordance with Fick’s second law of diffusion, a chloride diffusion equation in TRC layers under new boundary conditions was proposed.

Project Life INSUSHELL: Reducing the Carbon Footprint in Concrete Construction

Tomoscheit, Silke,Gries, Thomas,Horstmann, Michael,Hegger, Josef Sustainable Building Research Center 2011 International journal of sustainable building tech Vol.2 No.2

Within the Life INSU-SHELL project (Environmentally Friendly fa$\c{c}$ade Elements made of thermal insulated Textile Reinforced Concrete) RWTH Aachen University together with industrial partners developed and implemented an innovative and eco friendly modular system for sandwich fa$\c{c}$ades. The thin-walled, light-weight sandwich structure combines Textile Reinforced Concrete (TRC) and a PUR-rigid-foam-insulation. With the use of TRC a large quantity of concrete material and therefore $CO_2$-output can be avoided. The lower amount of concrete used in the new elements results in a reduction of $CO_2$-output of about 70% in comparison to a similar element of ferroconcrete. The lower weight saves energy and fuel. Moreover it reduces the pollutant emission in transport and application. The employment of the innovative elements at the new INNOTEX building (ITA: Institut fuer Textiltechnik of RWTH Aachen University) with a fa$\c{c}$ade size of about $590\;m^2$ saved large quantities of $CO_2$-output in comparison to conventional building techniques.

Bonding Behavior of TRC-Confined Concrete and Reinforcement under Chloride Erosion Environment

Lei Jing,Shiping Yin,Henglin Lv 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.3

The improved effect of the bonding behavior of concrete and reinforcement is a critical indicator for estimating the validity of strengthening measures. The bonding behavior of unconfined or textile reinforced concrete (TRC)-confined concrete and a plain or deformed reinforcement was comparatively analyzed via the pull-out tests, and the influence of chloride wet-dry cycles also was considered on the bonding behavior. Moreover, the bonding behavior was further revealed from the view of energy. The study results indicated that the bonding failure of specimens with a deformed reinforcement was changed after TRC confinement, showing a certain ductile failure characteristic, and the integrity of the confined specimens was ensured at failure. The impact of chloride attack on the bonding behavior of concrete and a plain or deformed reinforcement was different under the unconfined or TRC-confined condition. The deterioration mechanism of the bonding behavior needs to be further investigated when the reinforcement is corroded seriously. The results from the energy analysis are consistent with the pull-out test results.