scholarly journals Examination of Reinforcement Steel Bars Exposed to the Atmosphere

2020 ◽  
pp. 1-5
Author(s):  
Adejo O H ◽  
◽  
Ojo S A ◽  
Uzuh F U ◽  
Abere D V ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Sodium Chloride ◽  
Concrete Structures ◽  
The Other ◽  
Reinforced Concrete Structures ◽  
Reinforcement Steel ◽  
Corrosion Rates ◽  
Steel Bars ◽  
Steel Rebars ◽  
Strength And Ductility

Reinforcement steel bars are often exposed to the atmosphere before use in concrete structures. This exposure results in corrosion of these reinforcement bars. Corrosion of reinforcement bars is a common form of degradation of reinforced concrete structures. The electrochemical attack affects the mechanical properties of steel rebars. This study analysed the effect of exposing reinforcing steel bars to the atmosphere. The bars were divided into two; one part was exposed to the atmosphere for a period of four months during the rainy season while the other was unexposed. Afterwards; some mechanical, corrosion and metallographic tests were carried out on the steel samples. The results obtained showed that the hardness, impact strength and ductility increased with exposure while the yield and tensile strengths decreased with exposure. The exposed bar had high corrosion rates than the unexposed bar in 1M hydrochloric acid (HCl) while in 1M sodium chloride (NaCl), the corrosion rates for both the exposed and unexposed bars did not follow a particular trend

scholarly journals Examination of Reinforcement Steel Bars Exposed to the Atmosphere

2020 ◽  
pp. 1-5
Author(s):  
Adejo O H ◽  
Keyword(s):  
Mechanical Properties ◽  
Sodium Chloride ◽  
Concrete Structures ◽  
The Other ◽  
Reinforced Concrete Structures ◽  
Reinforcement Steel ◽  
Corrosion Rates ◽  
Steel Bars ◽  
Steel Rebars ◽  
Strength And Ductility

Reinforcement steel bars are often exposed to the atmosphere before use in concrete structures. This exposure results in corrosion of these reinforcement bars. Corrosion of reinforcement bars is a common form of degradation of reinforced concrete structures. The electrochemical attack affects the mechanical properties of steel rebars. This study analysed the effect of exposing reinforcing steel bars to the atmosphere. The bars were divided into two; one part was exposed to the atmosphere for a period of four months during the rainy season while the other was unexposed. Afterwards; some mechanical, corrosion and metallographic tests were carried out on the steel samples. The results obtained showed that the hardness, impact strength and ductility increased with exposure while the yield and tensile strengths decreased with exposure. The exposed bar had high corrosion rates than the unexposed bar in 1M hydrochloric acid (HCl) while in 1M sodium chloride (NaCl), the corrosion rates for both the exposed and unexposed bars did not follow a particular trend.

scholarly journals Bond-Slip Behavior between Stainless Steel Rebars and Concrete

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 979 ◽  
Author(s):  
Margherita Pauletta ◽  
Nicola Rovere ◽  
Norbert Randl ◽  
Gaetano Russo
Keyword(s):  
Stainless Steel ◽  
Reinforced Concrete ◽  
Carbon Steel ◽  
Service Life ◽  
Failure Modes ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Bond Behavior ◽  
Steel Bars ◽  
Steel Rebars

Maintenance of reinforced concrete structures is a prevailing topic, especially with regard to lifeline structures and bridges, many of which are now designed with a service life beyond 100 years. Reinforcement made of ordinary (carbon) steel may corrode in aggressive environments. Stainless steel, being much more resistant to corrosion, is a valid solution to facilitate the protection of the works, increasing the service life and reducing the need for repair and maintenance. Despite the potential for stainless steel to reduce maintenance costs, studies investigating the influence of stainless steel on the behavior of reinforced concrete structures are limited. This study investigated the bond behavior of stainless steel rebars by means of experimental tests on reinforced concrete specimens with different concrete cover thicknesses, concrete strengths, and bar diameters. In each case, identical specimens with carbon steel reinforcement were tested for comparison. The failure modes of the specimens were examined, and a bond stress–slip relationship for stainless steel bars was established. This research shows that the bond behavior of stainless steel rebars is comparable to that of carbon steel bars.

Effect of Minor Additives on First Stage Graphitisation in White Cast Iron

1984 ◽  
Vol 34 ◽  
Author(s):  
P. L. Roy ◽  
A. K. Chakrabart ◽  
P. Banerjee
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
Sodium Chloride ◽  
Yield Strength ◽  
White Cast Iron ◽  
Elemental Sulphur ◽  
Optimum Dose ◽  
White Iron ◽  
Kinetics Of ◽  
Strength And Ductility

ABSTRACTMinor additions (0.05-0.2 wt.%) of sodium chloride, hexachloroethane and elemental sulphur to commercial white iron melts have been found to enhance the kinetics of first stage graphitisation during subsequent annealing of white iron samples. The optimum dose of sodium chloride and hexachloroethane addition is around 0.1%. Yield strength and ductility of annealed test bars treated with NaCl or C2Cl6 compare favourably with those of untreated test bars. Sulphur treatment causes slight deterioration in mechanical properties. Fully grown nodules in both treated and untreated samples appear porous under SEM. Possible mechanisms of acceleration of graphitisation in the treated samples have been suggested.

Nonlinear Analysis of Bearing Capacity of Reinforced Concrete Structures Using Strip Method

2013 ◽  
Vol 470 ◽  
pp. 921-924
Author(s):  
Hai Chao Tan
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Nonlinear Analysis ◽  
Rectangular Cross Section ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Strip Method ◽  
Basic Assumptions ◽  
Steel Bars ◽  
Fortran Language

As the progress of theory and computer technology, nonlinear analysis is widely applied in civil engineering. Strip method, as one of the numerical methods, is used widely especially in the analysis of beams, columns and shell structures. The first half of this paper introduces the theoretical model and the basic assumptions of the strip method; the latter half of this paper compiles the strip method into computer program using FORTRAN language. At last, using beams with rectangular cross-section of reinforced concrete structures as an example, the paper analyze the factors, such as the strength of the steel bars, which have an impact on the bearing capacity of reinforced concrete structures.

Influence of NaCl on Mechanical Properties and Microstructure of Cement Stone

2013 ◽  
Vol 700 ◽  
pp. 136-139
Author(s):  
Xin Tang ◽  
Jin Huang
Keyword(s):  
Mechanical Properties ◽  
Sodium Chloride ◽  
Crystalline Phase ◽  
The Other ◽  
Cement Stone ◽  
X Ray Diffraction ◽  
X Ray ◽  
Main Crystalline Phase ◽  
Gel Phase ◽  
Scanning Electron

The mechanical properties and microstructure of cement stone containing different sodium chloride (NaCl) have been investigated. Uni-axial compression experiments were used to study mechanical properties. The main crystalline phase composition of cement specimens was determined by means of X-ray diffraction (XRD). Surface morphology of cement stone was observed by using scanning electron microscopy (SEM). The obtained results showed that compared with the other samples, the sample incorporated 14% sodium chloride was quite different, whose compressive strength was higher and microstructure was denser. The sodium chloride crystalline phase and the hydration (C-S-H) gel phase co-existed.

scholarly journals Historical reinforced concrete structures – used materials and calculating algorithms

2015 ◽  
Vol 14 (2) ◽  
pp. 105-112 ◽  
Author(s):  
Bartosz Szostak ◽  
Maciej Trochonowicz
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Structural Element ◽  
Historical Building ◽  
Historical Material ◽  
Low Strength ◽  
Concrete Elements

During designing in historical object we can have a problem with historical reinforced concrete elements. Many designers, classifies this elements as low strength. They are convicted that this type of elements in historical building can be only a monument and cannot be used in this construction as an structural element. It is very important in this type of buildings to keep as many historical material as it is possible. Authors researched the literature which has been a guide in the design and execution of these elements. By comprising used algorithms and physico-mechanical properties of old materials with algorithms and materials, which are using today, we are able to estimate the strength of such elements.

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