Fiber Bridging Degradation Based Fatigue Analysis of ECC under Flexure

Suthiwarapirak, Peerapong; Matsumoto, Takashi

doi:10.2208/journalam.6.1179

Cited by 19 publications

(10 citation statements)

References 5 publications

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“…According to the constitutive relation of UHTCC under tension, as shown in Fig. (a), after initial cracking, pseudo strain hardening turned up, and the deformation of UHTCC also developed linearly with a rather small increase in tensile strain. In this stage, no crack emerged in the concrete layer, and the deformation of this layer also behaved linearly on the basis of its tensile constitutive relationship, as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Flexural behaviour of UHTCC‐layered concrete composite beam subjected to static and fatigue loads

2013

Fatigue Fract Eng Mat Struct

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A B S T R A C T As an engineered material, ultra-high toughness cementitious composite (UHTCC) exhibits the characteristics of pseudo strain hardening and multiple cracking under uniaxial tension. It can be applied as the reinforcing and protective material of concrete structures. In this paper, static and fatigue flexural tests were carried out on UHTCC-layered concrete composite beams, for which UHTCC layer was used on the tension side. Under both static and fatigue loads, plane section assumption was suitable for such composite beams, and a good bond strength was achieved between the two layers. For static specimens, the UHTCC layer enhanced the ductility of the concrete layer. While under cyclic loads, because of the reinforcing effect of UHTCC, more than one crack were formed in the concrete layer, which led to a ductile deformation. Furthermore, the fatigue damage process of the composite beam was analysed.Keywords bending fatigue; fatigue damage process; interface bond strength; plane section assumption; UHTCC-layered concrete composite beam.N O M E N C L A T U R E S P cr = initial cracking load of the composite beam P C cr = initial cracking load of the concrete layer P U cr = initial cracking load of the layer of ultra-high toughness cementitious composite P cr = average initial cracking load of the composite beam P C cr = average initial cracking load of the concrete layer P U cr = average initial cracking load of the layer of ultra-high toughness cementitious composite P max = maximum value of fatigue loads P min = minimum value of fatigue loads P u = average ultimate load of static specimens S = fatigue stress level I N T R O D U C T I O NIn the past decades, concrete is the most widely used engineered material all over the world. However, because of its brittle performance, much money and labour have to be input to repair concrete structures. To improve these disadvantages, fibre reinforced concrete has been investigated in recent decades. One is ultra-high toughness cementitious composite (UHTCC), which exhibits the characteristics of multiple cracking and pseudo strain hardening under uniaxial tension. The UHTCC should simultaneously possess the following characteristics: 1 it is reinforced with short fibre with the corresponding volume fraction lower than 2.5%; the hardened composite exhibits significant pseudo strain-hardening and multiple-cracking behaviours with tensile strain capability above 3%; and, it can effectively keep the crack width below 100 mm even when the strain achieves its maximum value. The outstanding tensile and flexural behaviour of UHTCC is strongly connected to the achievement of a steady state condition of crack propagation. To produce multiple fine cracks, special proportion and appropriate fibre-matrix bond characteristics of UHTCC are required. 2 This engineered material also has some other excellent properties, such as ultra-high toughness, insensitivity to notches and good durability. 3,4 Besides, it can be used as the protective layer for steel bars

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Section: Resultsmentioning

confidence: 99%

Flexural behaviour of UHTCC‐layered concrete composite beam subjected to static and fatigue loads

2013

Fatigue Fract Eng Mat Struct

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“…To facilitate fatigue evaluation of the 15 material mixes shown above without completing millions of cycles of experimental fatigue loading, a fatigue model for ECC materials developed by Suthiwarapirak & Matsumoto (2004) is used. This model, based on previous work by Zhang (1998) and Suthiwarapirak & Matsumoto (2003), is shown as Equation 1.…”

Section: Estimation Of Service Lifementioning

confidence: 99%

Design of green engineered cementitious composites for pavement overlay applications

Lepech

Qian

et al. 2008

Life-Cycle Civil Engineering

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The construction, repair and rehabilitation of concrete pavements relies on the production and flow of large quantities of concrete and its constituents. Within the US, nearly 43 megatons of cement are used annually for the construction, repair and rehabilitation of concrete pavements, accounting for over 39 megatons of CO 2 emissions. To reduce environmental impact and improve the sustainability of pavement overlay systems, a class of materials called Engineered Cementitious Composites (ECC) has been designed for durable rigid pavement overlays.ECC overlays are designed to enhance sustainability in two ways. First, ''greener'' ECC materials incorporate high volumes of industrial wastes including fly ash, ground granulated blast furnace slag (GGBFS), and waste foundry sands and carbon residue to reduce the environmental impacts of material production. Fundamental micromechanics carefully guide the green material design to maintain pseudo-strain hardening material behavior under tension. This ductile behavior is critical to the second mechanism for sustainability enhancement. Through a distinct fracture phenomenon, the ductility of ECC effectively eliminates reflective cracking, a major cause of premature overlay failure, thereby increasing durability and reducing life-cycle maintenance. Experimental and theoretical analyses verify the green material and durable overlay design approaches. Incorporating industrial wastes, over 70% of ECC virgin constituents have been replaced without reducing critical mechanical performance characteristics. The combination of green raw materials, a 50% reduction in overlay thickness, and a doubling of service life as compared to concrete overlays, leads to significant sustainability improvements have been achieved. This paper presents the methodology and results of incorporating green cementitious materials design into rigid pavement overlay systems.

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“…Fatigue failure characteristics and fiber bridging characteristics of UHTCC under flexure were investigated and it was found that UHTCC exhibited significantly higher fatigue life and more ductility than concrete, polymer cement mortar and steel fiber reinforced concrete [21][22][23][24][25]. In addition, flexural fatigue behavior of concrete beams with UHTCC layer [26][27][28] and the tensile failure property of UHTCC under monotonic and cyclic tensile loads [29,30] has been studied.…”

Section: Introductionmentioning

confidence: 99%

Investigation on Compressive Fatigue Damage Process of Ultra-High Toughness Cementitious Composites

Huang

et al. 2016

Proceedings of the 9th International Conference on Fracture Mechanics of Concrete and Concrete Structures

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Ultra-high toughness cementitious composites (UHTCC) is a kind of cementitious material reinforced by random distributed short fibers, which was proposed by Li and Leung and was designed with micromechanical principles to achieve the strain hardening behavior. This material has potential use in particular environments and structures that experience repeated or fatigue loads. Considering that the fatigue behavior of ultra-high toughness cementitious composites under compression is crucial for its application in certain conditions (e.g. airport runway and road pavements) and fatigue damage of structural components might be affected by both the flexural and compressive fatigue behaviors, the available work is rather limited and a better understanding of the compressive fatigue behavior is required. In this study, a series of monotonic and fatigue tests were performed to investigate the fatigue behavior of this material under compression. Compressive fatigue tests were conducted on 32 cylinder specimens (70 mm in diameter and 140 mm in height). The loading frequency of fatigue tests was set as 4 Hz and the maximum stress was 90%, 85%, 80%, 75%, 70% and 65% of the compressive strength with the stress ratio (the ratio between the minimum fatigue loads to the maximum fatigue load) set constant as 0.1. The S -N relationship of ultra-high toughness cementitious composites was given, which indicates that the fatigue life of this material is higher than that of plain concrete and steel fiber reinforced concrete under the same stress level. It is observed that, the specimen failure mode of ultra-high toughness cementitious composites is similar to that of strain softening fiber reinforced concrete. The failure surface and damage process of this material were investigated. A new failure mode of PVA fiber with crush end was discovered with the help of SEM analysis and EDS analysis. This failure mode forms by the ruptured end of fibers experiencing repeated crushing and friction. Besides, based on the various failure modes of PVA fibers, the fatigue failure surface could be divided into three regions, including fatigue source region, transition region and crack extension region. During fatigue failure process, micro cracks initiate in the fatigue source region, propagate in the transition region and form main crack in the crack extension region.

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Fiber Bridging Degradation Based Fatigue Analysis of ECC under Flexure

Cited by 19 publications

References 5 publications

Flexural behaviour of UHTCC‐layered concrete composite beam subjected to static and fatigue loads

Flexural behaviour of UHTCC‐layered concrete composite beam subjected to static and fatigue loads

Design of green engineered cementitious composites for pavement overlay applications

Investigation on Compressive Fatigue Damage Process of Ultra-High Toughness Cementitious Composites

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