scholarly journals Toward Structural Health Monitoring of Civil Structures Based on Self-Sensing Concrete Nanocomposites: A Validation in a Reinforced-Concrete Beam

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Diego L. Castañeda-Saldarriaga ◽  
Joham Alvarez-Montoya ◽  
Vladimir Martínez-Tejada ◽  
Julián Sierra-Pérez
Keyword(s):  
Reinforced Concrete ◽  
Damage Detection ◽  
Direct Current ◽  
Health Monitoring ◽  
Electrical Resistance ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Structural Member ◽  
Rc Beam ◽  
Electric Resistance

AbstractSelf-sensing concrete materials, also known as smart concretes, are emerging as a promising technological development for the construction industry, where novel materials with the capability of providing information about the structural integrity while operating as a structural material are required. Despite progress in the field, there are issues related to the integration of these composites in full-scale structural members that need to be addressed before broad practical implementations. This article reports the manufacturing and multipurpose experimental characterization of a cement-based matrix (CBM) composite with carbon nanotube (CNT) inclusions and its integration inside a representative structural member. Methodologies based on current–voltage (I–V) curves, direct current (DC), and biphasic direct current (BDC) were used to study and characterize the electric resistance of the CNT/CBM composite. Their self-sensing behavior was studied using a compression test, while electric resistance measures were taken. To evaluate the damage detection capability, a CNT/CBM parallelepiped was embedded into a reinforced-concrete beam (RC beam) and tested under three-point bending. Principal finding includes the validation of the material’s piezoresistivity behavior and its suitability to be used as strain sensor. Also, test results showed that manufactured composites exhibit an Ohmic response. The embedded CNT/CBM material exhibited a dominant linear proportionality between electrical resistance values, load magnitude, and strain changes into the RC beam. Finally, a change in the global stiffness (associated with a damage occurrence on the beam) was successfully self-sensed using the manufactured sensor by means of the variation in the electrical resistance. These results demonstrate the potential of CNT/CBM composites to be used in real-world structural health monitoring (SHM) applications for damage detection by identifying changes in stiffness of the monitored structural member.

Application of Fly Ash-Based Geopolymer for Structural Member and Repair Materials

2014 ◽  
Vol 92 ◽  
pp. 74-83 ◽  
Author(s):  
Wanchai Yodsudjai
Keyword(s):  
Reinforced Concrete ◽  
Fly Ash ◽  
Concrete Beam ◽  
Setting Time ◽  
Reinforced Concrete Beam ◽  
Structural Member ◽  
Steel Reinforcement ◽  
Flexural Behavior ◽  
Fundamental Properties ◽  
Repair Materials

The applications of using fly ash-based geopolymer as a structural member and a repair materials in reinforced concrete structure was conducted. The optimum mix proportion of fly ash-based geopolymer concrete using for structural beam and fly ash-based geopolymer mortar using for repair material were developed. The flexural behavior of fly ash-based geopolymer reinforced concrete and the durability aspect namely the corrosion of steel reinforcement were investigated using the electrical acceleration. For the repair purpose, the fundamental properties; that is, compressive strength, flexural strength, bonding strength between fly ash-based geopolymer mortar and mortar substrate, setting time and chloride penetration were investigated. Also, the durability of conventional reinforced concrete beam repaired by the fly ash-based geopolymer mortar comparing with the comercial repair mortar was investigated. The behavior of the fly ash-based geopolymer reinforced concrete beam was similar to that of the conventional reinforced concrete beam; however, the corrosion of the steel reinforcement of the fly ash-based geopolymer reinforced concrete beam was higher than that of the conventional reinforced concrete beam. The fundamental properties of the fly ash-based geopolymer mortar were not different from that of the commercial repair materials; however, the durability of the reinforced concrete beam repaired by the fly ash-based geopolymer mortars performed a little lower than that of repaired with the commercial repair motar and also the control reinforced concrete with no repair. As a result, even there will be still a need of improvement there was a good tendency for using the fly ash-based geopolymer as the structural member and the repair materials.

Shear Failure of Patched Reinforced Concrete Beam without Web Reinforcements

2017 ◽  
Vol 737 ◽  
pp. 441-447 ◽  
Author(s):  
Stefanus Kristiawan ◽  
Agus Supriyadi ◽  
Senot Sangadji ◽  
Hapsara Brian Wicaksono
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Shear Failure ◽  
Unsaturated Polyester ◽  
Reinforced Concrete Beam ◽  
Concrete Cover ◽  
Patch Repair ◽  
Rc Beam ◽  
Diagonal Crack ◽  
The Web

Degradation of reinforced concrete (RC) element could lead to a reduction of its strength and serviceability. The degradation may be identified in the form of spalling of concrete cover. For the case of RC beam, spalling of concrete cover could occur at the web of the shear span due to corrosion of the web reinfocements. The shear strength of the damaged-RC beam possibly will become less conservative compared to the corresponding flexural strength with a risk of brittle failure. Patch repair could be a choice to recover the size and strength of the damaged-RC beam. This research investigates the shear failure of patched RC beam without web reinforcements with a particular interest to compare the shear failure behaviour of patched RC beam and normal RC beam. The patch repair material used in this research was unsaturated polyester resin (UPR) mortar. The results indicate that the initial diagonal cracks leading to shear failure of patched RC beam occur at a lower level of loading. However, the patched RC beam could carry a greater load before the diagonal crack propagates in length and width causing the beam to fail in shear.

FE Analysis on the Structural Behavior of Reinforced Concrete Beam Damaged by Fire

2013 ◽  
Vol 351-352 ◽  
pp. 743-746
Author(s):  
Soo Yeon Seo ◽  
Yu Gun Chung
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Fe Analysis ◽  
Structural Behavior ◽  
Rc Beam ◽  
Support Condition ◽  
Strength Deterioration ◽  
Simple Support ◽  
Analytical Result

This paper presents an analytical result about strength deterioration of reinforced concrete (RC) beams due to damage by fire. For the evaluation of the result, three RC beam specimens were made and two of those were exposed to fire. And then beam test was performed for those including non-heated specimen to evaluate the strength deterioration due to the fire damage under simple support condition. Strength decrease of materials due to the fire was evaluated through material test for concrete and reinforcements, respectively. Nonlinear Finite element (FE) analysis was performed by considering the decrease of materials due to fire. The analysis results showed that the structural behavior of fire-damaged RC beam was able to be simulated by using FE analysis with consideration of the reduction of material capacity due to fire.

scholarly journals Cracking Propagation and Pattern Behaviour of Irregular-Shaped Polyethylene Terephthalate Fibre Reinforced Concrete Beam

2015 ◽  
Vol 773-774 ◽  
pp. 911-915 ◽  
Author(s):  
J.M. Irwan ◽  
R.M. Asyraf ◽  
N. Othman ◽  
H.B. Koh ◽  
A.K. Aeslina ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Polyethylene Terephthalate ◽  
Concrete Beam ◽  
Volume Fraction ◽  
Reinforced Concrete Beam ◽  
Rc Beam ◽  
Materials Properties ◽  
Tensile Strength Test ◽  
Structural Test ◽  
Polyethylene Terephthalate Fibre

This paper reports the results on cracking propagation and pattern of reinforced concrete (RC) beam conducted using irregular-shaped Polyethylene Terephthalate (IPET) as a fibre. Three volume fraction of IPET fibre is used namely, 0.5%, 1% and 1.5%. All RC beam specimens are tested under four point loading under flexural capacity behaviour. Prior to structural test, the materials properties which include the compressive and tensile strength test and modulus of elasticity test were determined. The results than are compared with control RC beam. It is found that the RC beam with IPET fibre does not significantly change the behaviour of failure mode, cracking propagation and pattern compared to control RC beam.

Effective Method of Repairing RC Beam Using Externally Bonded Steel Plate

2014 ◽  
Vol 567 ◽  
pp. 399-404 ◽  
Author(s):  
Md Ashraful Alam ◽  
Ali Sami Abdul Jabbar ◽  
Mohd Zamin Jumaat ◽  
Kamal Nasharuddin Mustapha
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Steel Plate ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Steel Plates ◽  
Rc Beam ◽  
External Reinforcement ◽  
Externally Bonded ◽  
Damaged Beams

Repair of reinforced concrete beam with externally bonded steel plate or fibre reinforced polymer (FRP) laminate is becoming both environmentally and economically preferable rather than replacement of deficient beam. The well known advantages of external reinforcement over other methods include; low cost, ease of maintenance and the ability to strengthen part of the structure while it is still in use. The disadvantage of this method, however, is the premature debonding of the externally bonded strips which is brittle and undesired mode of failure. It is also known that debonding of the externally bonded steel plates prevents the reinforced concrete (RC) beam from reaching its full strengthening capacity. The aim of this study was to increase the scientific understanding on the behaviour of damaged reinforced concrete beams strengthened and/or retrofitted for shear using vertical steel plate fixed with adhesive and steel connectors to eliminate or delay debonding failure. Four reinforced concrete beam specimens were prepared to investigate the effects of connectors in preventing or delaying premature debonding of shear strips to restore the capacities of fully damaged beams. Three damaged beams have been repaired and strengthened with steel plates and loaded monotonically up to the maximum load capacities in order to define load–deflection relationship. It is concluded that the repairing of severely shear-damaged RC beams with steel plates by using steel and adhesive connectors can fully restore the original shear capacities of the beams.

scholarly journals THE EFFECTS OF INCLINED SHEAR REINFORCEMENT IN REINFORCED CONCRETE BEAM

2018 ◽  
Vol 30 (1) ◽  
Author(s):  
Nor Fazlin Zamri ◽  
Roslli Noor Mohamed ◽  
NurHafizah A. Khalid ◽  
Kang Yong Chiat
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Shear Failure ◽  
Reinforced Concrete Beam ◽  
Rc Beam ◽  
Rc Beams ◽  
Shear Reinforcement ◽  
Strain Behaviour ◽  
Different Types ◽  
Loading System

This paper presents the findings of an experimental data on the effects of inclined shearreinforcement in reinforced concrete (RC) beam. Two types of shear reinforcement of RC beamwere investigated, conventional stirrups (vertical links) and inclined shear reinforcement (45degrees of inclined shear reinforcement). The RC beam with conventional stirrups wasdesignated as a control specimen. The RC beams with different types of shear reinforcementwere tested for shear under four-point loading system. Comparisons were made between bothtypes of RC beam on load-deflection, load-steel strain, load-concrete strain behaviour and modeof failure. The theoretical and experimental were calculated by using conventional formulation inaccordance to EC 2 in order to verify the experimental results. From the results, it was observedthat the RC beam with 45 degree inclined shear reinforcement improved structural performancein shear by approximately 20% and thus prolong the shear failure behaviour as compared to theRC beam with vertical links.

Laminated Composite Beam with Bonded CFRP Reinforcement Stress Performance Analysis

2012 ◽  
Vol 204-208 ◽  
pp. 3160-3163
Author(s):  
Yong Wei Wang ◽  
Yan Qin Guo ◽  
Hong Xia Li
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Concrete Beam ◽  
Laminated Composite ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Rc Beam ◽  
Essential Difference ◽  
Cfrp Composite ◽  
Laminated Layer

Based on the test of 7 reinforced concrete beam reinforcement test data comparison analysis shows that only the ordinary reinforced concrete beams with externally bonded CFRP, effectively improve the bearing capacity of members, but due to the lower tensile reserves and the upper compression reserve is relatively insufficient, make a component similar over-reinforced beam brittle failure, its ultimate bearing capacity was significantly lower than the upper part at the same time a laminated layer of the RC beam. Laminated paste CFRP composite reinforced RC beam damage characteristics and common reinforced concrete beam was no essential difference, but the laminated layer thickness reaches to a certain degree, the CFRP can also occur with sudden local cleavage fracture.

Relationship between Half-Cell Potentials and Load Carrying Capacity of Corroded Reinforced Concrete Beam-Column Joints

2013 ◽  
Vol 351-352 ◽  
pp. 939-944
Author(s):  
Ming Li ◽  
De Jian Shen ◽  
Jie Yang ◽  
Zheng Hua Cui
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Carrying Capacity ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Rc Beam ◽  
Load Carrying Capacity ◽  
Half Cell ◽  
Load Carrying ◽  
The Relationship

This paper aims at detailed investigation on the relationship between half-cell potentials and load carrying capacity of corroded RC beam-column joints. There are four specimens in the test with the corrosion rate to 0%, 3%, 9% and 15%. Results show that the potentials of normal joint are larger than that of corroded damaged joints. As the corrosion rate of joints increases, load carrying capacity and half-cell potentials decrease. Analytical method based on the values of half-cell potentials to evaluate the load carrying capacity of corroded joint is presented. Comparing the analytical and experimental results, the proposed method can predict the load carrying capacity of corroded reinforced concrete beam-column joints.

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