Engineered Cementitious Composites Layer Research Articles

Large-scale model test study of the mechanical characteristics on sprayed ECC layer of highway tunnel under confining pressure

As the geological environment of highway tunnels becomes increasinlgy complex, sprayed engineered cementitious composites (ECC) has broad application prospects in the field of highway tunnel support. This study focuses on the shotcrete layer in the initial support of Wulingtou extra-long highway tunnel, the 1:4 scale model test of sprayed ECC layer under confining pressure was prepared. Its mechanical properties and real-time joint monitoring are determined using strain gauges, distributed optical fibers, and cameras. The results show that the maximum confining pressure of the sprayed ECC layer is 0.975MPa with the maximum displacement of 15.497cm, which outperforms ordinary shotcrete. The loading process of steel bars and sprayed ECC can be divided into three stages, with the change rate of these three stages showing an ascending trend. The failure mode is ductile, involving normal section, oblique section compression shear failure and bending shear failure. In addition, based on the similarity theory, the real mechanical characteristics of the sprayed ECC layer at the tunnel site can be predicted according to the experimental model.

Enhancement of cantilevered RC beams exhibiting inadequate lap spliced reinforcement using sustainable reinforced ECC layers

Designguidelines require an adequate overlap length for reinforcing bars, especially in extended spans of elements constructed from Reinforced Concrete (RC). Insufficient overlap can have adverse effects on key characteristics like bending strength and deformability of RC beams. The potential danger of failure in such elements is a significant concern as is considered a potential threat, and this study addresses it through experimental identification and numerical analysis to be mitigated carefully in this study to enhance the safety and sustainability of buildings to mitigate the risk of failure. The current investigation is centered on investigating the structural behavior of cantilevered RC beams exhibiting inadequate overlap between reinforcing bars in the hogging moment region. These beams have been strengthened through the application of ferrocement layers of Engineered Cementitious Composite (ECC). The experimental study consisted of eleven beams, which were categorized into four groups and subjected to bending loads until they reached failure. The research assessed various factors, such as the casting method (whether cast-in-situ or precast), the installation technique (involving the use of epoxy, or epoxy with anchors), and the length of the ECC layer. This layer was configured to have a length of 30Ø, 40Ø, and 50Ø, with Ø representing the diameter of the reinforcing bars along the zone subjected to hogging moments. According to findings, strengthening of specimens exhibiting insufficient steel overlap through an ferrocement ECC layer exhibited an improved overall structural behavior compared to the defective control beam. The most significant enhancement in both failure mode and load-deflection behavior was observed in beams strengthened through the incorporation of a cast-in-situ ECC layer with anchor bolts. Additionally, augmenting the strengthening length not only increased the initial stiffness of the reinforced beams but also enhanced their energy absorption capacity. Furthermore, the study involved the construction of a numerical simulation employing the Finite Element Method (FEM) simulating the observed behavior in experimentally tested beams. The model's precision was validated through a comparison of its results with the experimental data, revealing a satisfactory level of accuracy.

Flexural behavior of RC beams reinforced by ECC layer and steel plate: numerical simulation

PurposeThe combination of an Engineered Cementitious Composite (ECC) layer and steel plate to reinforce RC beams (ESRB) is a new strengthening method. The ESRB was proposed based on the steel plate at the bottom of RC beams, aiming to solve the problem of over-reinforced RC beams and improve the bearing capacity of RC beams without affecting their ductility.Design/methodology/approachIn this paper, the finite element model of ESRB was established by ABAQUS. The results were compared with the experimental results of ESRB in previous studies and the reliability of the finite element model was verified. On this basis, parameters such as the width of the steel plate, thickness of the ECC layer, damage degree of the original beam and cross-sectional area of longitudinal tensile rebar were analyzed by the verified finite element model. Based on the load–deflection curve of ESRB, ESRB was discussed in terms of ultimate bearing capacity and ductility.FindingsThe results demonstrate that when the width of the steel plate increases, the ultimate load of ESRB increases to 133.22 kN by 11.58% as well as the ductility index increases to 2.39. With the increase of the damage degree of the original beam, the ultimate load of ESRB decreases by 23.7%–91.09 kN and the ductility index decreases to 1.90. With the enhancement of the cross-sectional area of longitudinal tensile rebar, the ultimate bearing capacity of ESRB increases to 126.75 kN by 6.2% and the ductility index elevates to 2.30. Finally, a calculation model for predicting the flexural capacity of ESRB is proposed. The calculated results of the model are in line with the experimental results.Originality/valueBased on the comparative analysis of the test results and numerical simulation results of 11 test beams, this investigation verified the accuracy and reliability of the finite element simulation from the aspects of load–deflection curve, characteristic load and failure mode. Furthermore, based on load–deflection curve, the effects of steel plate width, ECC layer thickness, damage degree of the original beam and cross-sectional area of longitudinal tensile rebar on the ultimate bearing capacity and ductility of ESRB were discussed. Finally, a simplified method was put forward to further verify the effectiveness of ESRB through analytical calculation.

Impact of SCMs and fibres in ECC on the fire resistance of hot-jointed SCC/ECC composites

The influence of various supplementary cementitious materials (SCMs) and fibres on the fire resistance of composite systems that combine engineered cementitious composites (ECCs) in tension with self-compacting concrete (SCC) in compression was examined. The study was designed to determine the ideal ECC formulation for optimising mechanical properties and bonding performance at ambient and elevated temperatures. The SCC and ECC were hot-joined without vibration or surface preparation, using a fresh-to-fresh casting method. Modifications to the chemical composition of the ECCs included the addition of class F fly ash (FAF), class C fly ash (FAC) or slag, as well as polyvinyl alcohol (PVA) fibres or steel fibres. The samples were exposed to temperatures of 200°C, 400°C, 600°C and 800°C, followed by comprehensive testing to evaluate their flexural strength, tensile strength and interfacial properties. The results indicate that the incorporation of an ECC layer within the SCC system significantly improved mechanical strength and thermal stability, both at ambient temperatures and under high-temperature conditions. Notably, the addition of FAF (rather than FAC or slag) in the ECC layer offered superior thermal stability and ensured the retention of desirable residual mechanical properties. Moreover, steel fibre reinforcement greatly improved the SCC/ECC bonding, outperforming PVA reinforcement at elevated temperatures.

Shear Strengthening of Reinforced Concrete Beams Using Engineered Cementitious Composites and Carbon Fiber-Reinforced Polymer Sheets

This study evaluates the performance of Reinforced Concrete (RC) beams enhanced in shear using Engineered Cementitious Composites (ECCs) and Carbon Fiber-Reinforced Polymers (CFRPs). The experimental study encompasses fifteen RC beams. This set includes one control specimen and fourteen beams fortified in shear with Externally Bonded (EB) composites. Two of these specimens were enhanced with ECC layers, while the remaining were augmented with combined CFRP-ECC layers. Variables in the test included the ECC layer thickness, matrix type, number of CFRP layers, and strengthening configurations such as full wrapping, vertical strips, and inclined strips. The results indicated that the shear capacity of the fortified beams increased by 61.1% to 160.1% compared to the control specimen. The most effective structural performance was observed in the full wrapping method, which utilized a single CFRP layer combined with either 20 mm or 40 mm ECC thickness, outperforming other techniques. However, the inclined strip method demonstrated a notably higher load-bearing capacity than the full wrapping approach for beams with double CFRP layers paired with 20 mm and 40 mm ECC thicknesses. This configuration also exhibited superior ductility compared to the rest. Furthermore, the experimental shear capacities obtained were juxtaposed with theoretical values from prevailing design standards.

Efficient prediction of the load-carrying capacity of ECC-strengthened RC beams – An extra-gradient boosting machine learning method

As a result of the excellent crack width control capabilities of engineered cementitious composites (ECC), an ECC layer located in tension zones in reinforced concrete structures can transform wide harmful cracks into harmless dense microcracks. As a result, reinforced concrete structures are more durable and less prone to corrosion in aggressive environments. In the literature, there are equations that can predict the flexural capacity of ECC-strengthened RC beams. However, these equations are primarily regression-based and contain a limited number of parameters. With the help of the machine learning (ML) technique, a more comprehensive equation considering all the governing parameters can be proposed for ECC-strengthened RC beams. In the present study, a large database containing data from 217 ECC-strengthened beam specimens was collected from around two dozen publications. These data were then employed to develop an ML model using the XG boost algorithm. The model uses 20 input variables to predict the load-carrying capacity of the ECC-strengthened beam. The optimal model can produce a predicted-target dataset for the test dataset with an accuracy level of above 80%. Model parameters with the greatest significance according to Gini indexes were yield strength of the steel bars in the concrete substrate, beam depth, longitudinal reinforcement area, and ECC thickness. The analysis of SHAP (an acronym for SHapley Additive Explanations) values revealed a consistent pattern from the optimized model. Eventually, the study offers a free and easy-to-use graphical user interface to facilitate user interaction with the developed XG Boost model.

Blast resistance of ECC and composite slabs subjected to near-field explosion

Due to the unfavorable blast resistance of reinforced concrete (RC) slabs, particularly with the frequent occurrence of penetration and spalling damage, engineered cementitious composite (ECC) provided a promising alternative for enhanced blast resistance through its direct application as a building material or by reinforcing existing RC slabs due to its excellent tensile ductility and toughness. In the present study, the blast resistance of the RC slab, the ECC slab, and the composite slab (RC slab reinforced by ECC layer) was investigated and compared through experimental and numerical approaches. Firstly, the material properties of the ECC were acquired through the quasi-static compressive test, as well as quasi-static and dynamic tensile tests, which felicitated the parameter calibration in the K&C model for ECC. Then the numerical models of the RC slab, the ECC slab, and the RC/ECC composite slab were established and validated with the blast test results. The test and numerical results showed that the ECC and composite slabs exhibited superior anti-blast performance in terms of failure mode, damage extent, and load mitigation compared to the RC slab. Owing to the remarkable ductility and toughness, the ECC and composite slabs could greatly reduce the possibility and severity of penetration and spalling damage. Furthermore, five significant parameters impacting the blast resistance of ECC and composite slabs were summarized through dimensional analysis including the tensile strength of ECC σt, the total explosive energy Q, the standoff distance R, the slab thickness H, and the slab span L. Then a dimensionless number was proposed to determine the failure mode and predict the residual deflection at the center of the ECC and composite slabs. The results could serve as a reference for the design of ECC and composite slabs to resist blast loading in the field of structural protection.

Axial compression test on concrete columns hybrid strengthened with CFRP/CPVC tube and ECC cladding layers

Existing research proved that the confinement of fiber-reinforced polymer (FRP) and commercially available chlorinated polyvinyl chloride (CPVC) tubes can considerably improve the strength and ductility of concrete columns. Meanwhile, engineered cementitious composite (ECC), as a kind of high-ductility and high-energy absorbing material, can effectively improve the ductility of concrete columns. In this study, a novel hybrid system was proposed, including the hybrid confinement of carbon fiber-reinforced polymer (CFRP) and CPVC, and an inner ECC layer. Its compressive behavior was explored by the axial compression test, and the effects of the number of CFRP layers, the diameter of the CPVC tubes, and the net spacing of the CFRP strips were considered as the test variables. The test results showed that CFRP-CPVC confinement can significantly improve the peak strength and corresponding strain of cylinders, and the inner ECC layer can enhance the relative ductility. Compared to the diameter of the CPVC tube and the net spacing of CFRP strips, thicker CFRP layers and full CFRP wrapping noticeably improved the loading capacity of the specimens. Finally, a theoretical model was given for predicting the peak axial stress of the specimens, which can provide a reference for designing the hybrid strengthening system.

Effect of fire exposure on the bonding behavior of hybrid engineered composite systems

When used with self-compacting concrete (SCC) in a fresh state, engineered cementitious composites (ECC) can enhance flexural properties and durability. There is, however, some uncertainty as to whether the composites and their related interfacial bonds will endure high temperatures. This article investigates how fire exposure affects hot-jointed concrete systems (CS) that combine SCC and ECC. Residual flexural and tensile properties and possible degradation/debonding of the interfacial zone after exposure to 800 °C were examined, considering the effect of three different fiber types (i.e. polyvinyl alcohol (PVA), steel (SF), and hybrid PVA/steel fibers) in the tension ECC layer. Visual, microstructural, ultrasonic pulse velocity and mass loss properties were assessed for air- and water-cooled specimens. Also, mathematical models were proposed based on the results of each concrete composite. ECC added to SCC at fresh-to-fresh state significantly increased its flexural and splitting tensile resistance, as well as thermal integrity. All composites were negatively affected by fire, but composite systems maintained their interfacial bond without excessive degradation. It was also determined that fibers at the interface area of composite systems are crucial to preserving their mechanical and physical bonding under fire, thus SF resulted in higher thermal resistance compared to PVA.

Flexural behaviour of high strength engineered cementitious composites (ECC)-reinforced concrete composite beams

The flexural behaviour is investigated in this paper for engineered cementitious composite (ECC)-reinforced concrete (RC) composite beams. The thickness and shape of the ECC layer are the variables studied. ECC has proved to be one of the ideal construction materials for improving the flexural capacity of reinforced conventional concrete beams. When the composite beam specimens reached the load-bearing limit state, only dense micro-cracks appeared in the ECC layer in the tensile zone, and no local fracture was observed in the test, reflecting the high ductility of ECC. The load values for all phases of the ECC-RC composite beams are higher than those of the RC beams, suggesting that the composite beams have better ductility and energy absorption capacity. In addition, the ability of the U-shaped ECC layer composite beam to limit crack development and the synergistic effect with the reinforcement is superior compared to the other tested beams. Finally, considering the strain-hardening characteristics of ECC, based on the force equilibrium conditions, the formulae are derived for the flexural capacity of ECC-RC composite beams.

Flexural Performance of Composite RC Beams Having an ECC Layer at the Tension Face

This paper presents an experimental study on the flexural behavior of composite Reinforced Concrete (RC) beams having a monolithic Engineered Cementitious Composites (ECC) layer at the tension face. Due to the brittle nature of normal concrete, clear cover on the tension side of beam cracks results in spalling and corrosion of reinforcement. The proposed technique overcomes the inherent brittle behavior of normal concrete with the incorporation of ECC on the tension face. This also helps in reducing bond-splitting, cover-spalling, and buckling of reinforcement in RC flexural members. For testing purposes, six full-scale beam specimens (225 mm x 300 mm x 2400 mm) with the same reinforcement were cast and tested. Out of six, two specimens were made of conventional concrete, whereas the remaining four (two each) had an ECC layer of 75mm and 100mm thick at the tension face respectively. Each specimen was installed with three strain gauges (one each at the midspan top & bottom surface of concrete and one midspan rebar on the tension face) and one LVDT at midspan. The samples were then subjected to simple monotonic loading under a third-point bending test as per ASTM C78. The load-displacement, stress-strain and moment-curvature curves were obtained for all the tested specimens. It was found that ECC-strengthened beam samples displayed an increased flexural performance at first crack, yield, and ultimate load-carrying capacity as compared to conventional RC specimens. Whereas a better crack arrest with even distribution of cracks and improvement in ductility was observed for the ECC-strengthened composite beams.

Performance of engineered cementitious composite (ECC) monolithic and composite slabs subjected to near-field blast

To improve the performance of reinforced concrete (RC) structural members subjected to blast, especially the spalling due to the brittleness of concrete, engineered cementitious composite (ECC) was applied in monolithic and composite slabs and their responses subjected to near-field blast were experimentally investigated in the present study. First, two different ECC materials were prepared and tested with quasi-static direct tension and flexural tests, whose results showed significantly improved tensile ductility and strength compared to normal concrete. Then a field test was conducted to investigate the response of ECC monolithic and composite slabs under near field blast, with an RC slab as reference. The responses of these slabs were compared in terms of response mode, residual deformation, crack initiation and development, spalling, strain time history, etc. The test observations suggested that in addition to the ductile response and failure of ECC subjected to quasi-static direct tension and flexural tests, ECC still exhibited ductile response at high strain rate when applied in monolithic and composite slabs under near field blast. Compared to the perforation and spalling of RC slab, the ECC monolithic or composite slabs underwent large deformation, until collapse failure with a major crack in the mid-span occurred. Importantly, throughout the whole response process, even the ECC monolithic and composite slabs collapse with a major crack at mid-span, no spalling was observed. Furthermore, no delamination occurred in the interface between the RC and ECC layer of the RC/ECC slabs. Both the ECC monolithic slab and RC/ECC composite slab exhibited favorable performance subjected to near-field blast. These observations implied that the ECC is promising in the potential application of structural protection against blast, not only for replacing certain key components in the newly built structures but also for retrofitting existing RC structures.

Flexural capacity of RC beams reinforced with ECC layer and steel plate

This paper presents the results of constructing reinforced concrete (RC) beams with Engineered Cementitious Composite (ECC) layers and steel plates. Among the eleven sample beams tested under static loading, one was not reinforced, two were reinforced with steel plates (steel RC beams), and the other eight were reinforced with both ECC layers and steel plates (ECC + steel RC beams). Besides, this test adopted the following variables: the connection mode between an ECC layer and an RC beam, the thickness of an ECC layer, and the cross-section area of a steel plate. It can be observed that the combination of the ECC layer and the steel plate on an RC beam significantly delayed the formation and development of cracks, thereby enhancing the over-reinforcement of the steel RC beams, as well as increasing their flexural capacity and ductility. Furthermore, the ultimate load for the ECC + steel RC beams was insignificantly affected by the differences in the connection mode. In addition, the flexural capacity of an ECC + steel RC beam increased as the thickness of the ECC layer and the cross-sectional area of the steel plate increased.

Effect of using Engineered Cementitious Composites (ECC) on failure behavior of flat slab-column connections

Load capacity and ductility are two key characteristics of the flat slab-column connection in high seismic areas. This study specifically examined the effect of strengthening layer thickness of Engineered Cementitious Composites (ECC) on punching shear strength and post punching behavior of flat slabs. The effect of the unbalanced moment, ECC thickness of the slab and the strengthening ECC layer on flat slab punching and post punching behavior were also investigated. Thirteen reinforced concrete flat slab specimens were made and examined. It was observed that the replacement of slab concrete with ECC increased the punching capacity and improved post-punching behavior without a large and sudden drop in load. In addition, the use of ECC as a strengthening layer for the flat slabs significantly increased the punching and post-punching shear strength capacities. The change in failure mechanism was observed from a sudden and abrupt failure to a ductile failure with high-energy absorption when more ECC layer thicknesses were used.

Effect of Using ECC Layer on the Flexural Performance of RC Beams Previously Strengthened with EB CFRP Laminates

This paper studies the efficiency of applying an engineered cementitious composite (ECC) layer to the tensile surface of (RC) beams that were previously strengthened using externally bonded (EB) carbon fiber-reinforced polymer (CFRP) laminates. One control and ten strengthened RC beams were produced and tested utilizing a four-point loading regime. For strengthened beams, two beams were kept strengthened using only CFRP, and additional ECC layers were added to the rest of the strengthened beams. The CFRP width and overlap length and position were among the test factors. Experimental results revealed that strengthening RC beams with CFRP laminates enhanced both the stiffness and flexural capacity of beams. Additional enhancements were obtained through the application of the additional ECC layers. The existence of the ECC layer alongside the CFRP laminate improved the flexural capacity by 102% and 125% when using CFRP widths of 50 mm and 100 mm, respectively, and the stiffness was improved by an average value of 318%. Three-dimensional (3D) finite element models (FEMs) were developed using ABAQUS software and verified against the experimental results to model the response of the tested beams. The verified model was used to conduct a parametric study to consider the effect of the ECC layer thickness and the reinforcement ratio on the strengthened beam behavior. The numerical results revealed that the effect of the reinforcement ratio was more significant than the ECC layer thickness in enhancing the load-displacement response, especially after the cracking stage.

Experimental and numerical analysis of RC beams strengthened with ECC and stainless steel strips

Strengthening of reinforced concrete (RC) structures may be required for several reasons and flexural strengthening of normal concrete (NC) beams is widely carried out using laminated fibres. However, the incompatibility of the concrete cover can lead to fibre debonding or concrete cover dislocation. These are some of the critical setbacks in common practice and the cost of fibre can be high. A novel flexural strengthening technique for NC beams is thus proposed: durable strips of stainless steel plate (SSP) bonded over a engineered cementitious composite (ECC), which is in complete contact with the flexural reinforcement of a slave beam through shear connectors. The flexural behaviour of NC beams strengthened with ECC and SSP strips was investigated experimentally and numerically. Three variables were investigated: the thickness of the SSP, the ECC layer with or without deformed steel bars and three different strengthening techniques. The experimental results showed that hybrid ECC–SSP strengthening improved the ultimate capacity of the NC beams by as much as 156%. A three-dimensional finite-element model (FEM) was developed and validated using the experimental results. The FEM accurately predicted the experimentally observed flexural behaviour of the NC beams with hybrid ECC–SSP strengthening. An analytical model to predict the ultimate load of NC beams with hybrid ECC–SSP strengthening was also developed.

Experimental and numerical investigations of the effectiveness of engineered cementitious composites and stainless steel plates in shear strengthening of reinforced concrete beams

AbstractThis paper investigates the shear strengthening of reinforced concrete (RC) beams incorporating engineered cementitious composite (ECC) and stainless steel plates (SSPs). The use of ECC, characterized by strain‐hardening in conjunction with SSPs, was investigated in this study to improve the shear performance of RC beams. Total 10 RC beams were tested under static loading up to failure to investigate a few key parameters, namely: material of strengthening (ECC and SSPs), the thickness of ECC, and shape and configuration of SSPs. Experimental findings showed that the proposed strengthening methods can significantly improve the failure pattern and increase the ultimate shear capacity of the studied RC beams by 36%–97% compared to the unstrengthened beam. Experimental results were compared against the predicted ultimate shear strength of RC beams using design equations specified by various design codes. Nonlinear three‐dimensional finite element modeling was developed for beams strengthened with ECC layer and validated against the test results and found to be accurate. Based on the experimental and numerical results, new shear capacity formulae were proposed considering the ratio of ECC‐to‐concrete beam cross‐section (ρECC) and then verified against the numerical predictions.

Research on Impact Resistance of Reinforced Concrete Beams Strengthened with Carbon Fiber Reinforced Polymer Grid and Engineered Cementitious Composites.

When reinforced concrete structures are subjected to impact loads, they may suddenly yield or fail, or even collapse as a whole. In this paper, the impact resistance of reinforced concrete (RC) beams strengthened with carbon fiber reinforced polymer (CFRP) grid and engineered cementitious composites (ECC) was studied. Drop hammer impact tests were conducted on eight beams, then the finite element model was used to simulate the impact test, finally a simplified two-degree-of-freedom (TDOF) model was proposed for CFRP grid reinforced ECC layer strengthened RC beams under impact loading. The results showed that CFRP grid reinforced ECC layer significantly improved the impact resistance of RC beams. When the ECC and CFRP grid were used, the crack development was inhibited after the concrete cracked in the tensile area, avoiding the brittle damage of concrete beams with one crack to the end. Compared with the control beam, the reaction force of RC beams strengthened with CFRP grid and ECC under impact load increased by 16.2%~34.5%, the maximum mid-span displacement decreased by 16.3%~31.6% and the mid-span residual displacement decreased by 36.02%~49.53%. The finite element model and the proposed TDOF mode were demonstrated to effectively simulate the strengthened beam under impact loading.

Fatigue performance of corrosion-damaged beams strengthened with FRP grid-reinforced ECC matrix composites

An investigation on the flexural fatigue behavior of corrosion-damaged reinforced concrete (RC) beams that were strengthened with a fiber-reinforced polymer (FRP) grid-reinforced engineered cementitious composite (ECC) matrix is presented in this paper. The concrete cover, which was damaged by the corrosion of the tensile steel bars, was chipped away and reinstated with an ECC layer that was embedded with an FRP grid. A total of 12 beams were constructed, and 11 of them were subjected to cyclic fatigue loading. The test results indicated that the final failure mode of the strengthened beams was still dominated by the brittle fracture of the tensile steel reinforcements. The fatigue life of the beams increased significantly with increasing strengthening amounts of the FRP grid but decreased with the corrosion ratio and the upper limit fatigue load level. At a sufficient strengthening amount, the fatigue life of strengthened beams could be restored to that of the original uncorroded beams. By regression analysis of the stress range–fatigue life (S–N) curve, a prediction formula for fatigue life was derived with a satisfactory correlation coefficient. In addition, the tested midspan deflections and the results that were calculated using available empirical models or theoretical calculation approaches were compared and evaluated.

Shear strengthening of reinforced concrete beams with high-strength steel wire and engineered cementitious composites

Engineered cementitious composite (ECC) is a type of high-performance fibre-reinforced cementitious composite with good ductility and excellent crack control ability. It has attracted increasing attention as a structural repair material in severely corrosive environments. However, the strength improvement is limited when ECC is used alone for shear strengthening of existing reinforced concrete (RC) members, although its shear capacity is much higher than that of other brittle cementitious materials such as cement mortar. This study proposes a novel shear strengthening method for RC beams with both high load-carrying capacity and good durability through the combination of high-strength steel wire and an ECC layer. The shear behaviours of the beams were tested under static loading. The test results showed that the shear strength and the ultimate displacement were significantly improved through shear strengthening. A large number of fine cracks appeared on the ECC layer before the failure of the beams. The load-carrying capacity was reduced by pre-damage owing to the important role of the shear resistance of the concrete with respect to the total shear capacity. The shear strength of the strengthened beams cannot be accurately predicted by the current design code owing to the ignorance of the shear resistance of ECC.