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

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.

2015 ◽  
Vol 23 (4) ◽  
pp. 1-7 ◽  
Author(s):  
Jamal Khatib ◽  
Adrian Jefimiuk ◽  
Sammy Khatib

Abstract The flexural properties of reinforced concrete beams containing expanded glass as a partial fine aggregate (sand) replacement are investigated. Four concrete mixes were employed to conduct this study. The fine aggregate was replaced with 0%, 25%, 50% and 100% (by volume) expanded glass. The results suggest that the incorporation of 50% expanded glass increased the workability of the concrete. The compressive strength was decreasing linearly with the increasing amount of expanded glass. The ductility of the concrete beam significantly improved with the incorporation of the expanded glass. However, the load-carrying capacity of the beam and load at which the first crack occurs was reduced. It was concluded that the inclusion of expanded glass in structural concrete applications is feasible.


2013 ◽  
Vol 351-352 ◽  
pp. 927-932
Author(s):  
Zheng Hua Cui ◽  
De Jian Shen ◽  
Cong Bin Huang ◽  
Ming Li

This paper addresses the results of an experimental study on relationship between half-cell potentials and load carrying capacity of corroded concrete RC shear walls. There are four specimens in the test with the corrosion rate of 0%, 3%, 9% and 15%, respectively. Before and after the accelerate corrosion test, half-cell potential measurement was used to attain half-cell potentials. The horizontal load carrying capacity was attained under cyclic loading. Results show that load carrying capacity of corrosion damaged walls decrease with the increase of corrosion rate, as well as half-cell potentials. The relationship among corrosion rate, half-cell potentials and load carrying capacity is presented.


Abstract. Concrete is the predominant material in the construction industry. To be sustainable, the old Reinforced Concrete (RC) buildings should be retrofitted, and the life of the building should be extended. Experimental study has been attempted to investigate the load carrying capacity of concrete beam strengthened with glass fiber and banana fiber mat. The primary aim of this study is to retrofit the RC beam specimen to enhance the load carrying capacity. All the beams were casted with the same grade of concrete (M30) and same structural detailing. Two-point symmetrical loading were given to the control beams to obtain load at initial crack and ultimate load. Then the beams other than control beams were loaded till it showes initial crack and then retrofitted with banana fiber and glass fiber bonded externally with resin. The retrofitted beams were tested for ultimate load performance. Load carrying capacity was higher for both retrofitting but the beam retrofitter with glass fiber showed significant improvement in the ultimate load carrying capacity.


2021 ◽  
Vol 9 (ICRIE) ◽  
Author(s):  
Ali I. Salahaldin ◽  
◽  
Muyasser M. Jomaa’h ◽  
Dlovan M. Naser ◽  
◽  
...  

One of the most common methods of strengthening, rehabilitation, or repairing of structural lightweight concrete (LWC) elements is the external carbon fiber reinforced polymer (CFRP) strips. This paper presents an experimental study on the flexural behavior of reinforced concrete beams which comprise lightweight aggregate concrete, in different proportions, strengthened by CFRP sheets. The experimental program included six specimens with a 1500mm effective span. Two of the specimens were normal concrete beams. Another two samples were lightweight beams with a 50% aggregate replacement with pumice. The last two specimens were lightweight concrete beams with a 75% aggregate replacement with pumice. These beams were casted and tested twice under a two-point load application, once before strengthening and the other after that. The experimental results show that full strengthening of the beams along with their entire length, increase in load-carrying capacity by 75%, 113%, and 107% for normal concrete beam, (50% aggregate replacement) LWC beam, and (75% aggregate replacement) LWC beam respectively. While the middle-third strengthening of the beams shows an increase in load-carrying capacity by 64%, 72%, and 57% for normal concrete beam, (50% aggregate replacement) LWC aggregate beam, and (75% aggregate replacement) LWC beam respectively. The strength of the two types of LWC beams was almost the same and it is about 85% of the concrete beam with normal weight.


Author(s):  
Agus Maryoto ◽  
Han Aylie ◽  
Hendriks Marius Jonkers

A galvalume corrugated sheet was utilized as formwork for a reinforced concrete beam in flexure. A numerical model was validated to the experimentally obtained data, and further adopted to simulate the behavior of this composite structure under elevated temperatures. The properties and constitutive stress-strain data of the basic materials were obtained from experiments, and superimposed into the finite element model. The study concluded that the load carrying capacity of the member decreased as a direct function on temperature increase, and the cracking moment was very sensitive to the temperature fluctuation. The elevated temperatures also altered the failure mode.


2018 ◽  
Vol 4 (7) ◽  
pp. 1595
Author(s):  
Nibras Abbas Harbi ◽  
Amer F. Izzet

The performance of composite prestressed concrete beam topped with reinforced concrete flange structures in fire depends upon several factors, including the change in properties of the two different materials due to fire exposure and temperature distribution within the composition of the composite members of the structure. The present experimental work included casting of 12 identical simply supported prestressed concrete beams grouped into 3 categories, depending on the strength of the top reinforced concrete deck slab (20, 30, and 40 MPa). They were connected together by using shear connector reinforcements. To simulate the real practical fire disasters, 3 composite prestressed concrete beams from each group were exposed to high temperature flame of 300, 500, and 700°C, and the remaining beams were left without burning as reference specimens. Then, the burned beams were cooled gradually by leaving them at an ambient lab condition, after which the specimens were loaded until failure to study the effect of temperature on the residual beams serviceability, to determine the ultimate load-carrying capacity of each specimen in comparison with unburned reference beam, and to find the limit of the temperature for a full composite section to remain composite. It was found that the exposure to fire temperature increased the camber of composite beam at all periods of the burning and cooling cycle as well as the residual camber, along with reduction in beam stiffness and the modulus of elasticity of concrete in addition to decrease in the load-carrying capacity.


Author(s):  
Diego L. Castañeda-Saldarriaga ◽  
Joham Alvarez-Montoya ◽  
Vladimir Martínez-Tejada ◽  
Julián Sierra-Pérez

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.


Sign in / Sign up

Export Citation Format

Share Document