scholarly journals Corrosion studies on XD3 reinforced concrete samples prepared by using calcium nitrate as inorganic corrosion inhibitor with different superplasticizers

2020 ◽  
Vol 64 (1) ◽  
pp. 11-18
Author(s):  
S. A. Abdulsada ◽  
R. Bak ◽  
A. Heczel ◽  
T. I. Török
Keyword(s):  
Reinforced Concrete ◽  
Room Temperature ◽  
Calcium Nitrate ◽  
Inhibition Mechanism ◽  
Test Results ◽  
European Standard ◽  
Corrosion Properties ◽  
Steel Reinforced Concrete ◽  
Corrosion Studies ◽  
Nitrate Anions

AbstractThis research paper presents an analysis of the corrosion properties of steel-reinforced concrete samples during immersion in 3.5 wt. % NaCl aqueous solution by measuring their response both cathodic and anodic polarization in order to determine the corrosion rates in the function of their calcium nitrate inhibitor content. This cheap inorganic inhibitor was added to the concrete mix in concentrations of 1% and 3% by weight of cement in addition to two different superplasticizers (MapeiDynamon SR 31 and Oxydtron). The compressive strengths of the so prepared samples were also checked according to the relevant European standard and were within the acceptable limits, so this inhibitor does not weaken this important property of the concrete samples.The test results on steel reinforced samples immersed in 3.5 wt. % NaCl aqueous solutions at room temperature showed promising corrosion mitigating effects just after 6 months testing period. After 6 months the lower corrosion currents (i.e. better corrosion resistance) for both types of superplasticizers were observed with those samples which contained 3% calcium nitrate inhibitor. The best result was observed with sample C4 (in this case 3% calcium nitrate was added to the mixture of cement+Oxydtron superplasticizer). The advantageous inhibition mechanism of nitrate anions is also discussed and interpreted.

scholarly journals Analysis and Modification of Methods for Calculating Axial Load Capacity of High-Strength Steel-Reinforced Concrete Composite Columns

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6860
Author(s):  
Jun Wang ◽  
Yuxin Duan ◽  
Yifan Wang ◽  
Xinran Wang ◽  
Qi Liu
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
High Strength Steel ◽  
Slenderness Ratio ◽  
High Strength ◽  
Confinement Effect ◽  
Test Results ◽  
Composite Columns ◽  
Steel Reinforced Concrete ◽  
Modified Formula

To investigate the applicability of the methods for calculating the bearing capacity of high-strength steel-reinforced concrete (SRC) composite columns according to specifications and the effect of confinement of stirrups and steel on the bearing capacity of SRC columns. The axial compression tests were conducted on 10 high-strength SRC columns and 4 ordinary SRC columns. The influences of the steel strength grade, the steel ratio, the types of stirrups and slenderness ratio on the bearing capacity of such members were examined. The analysis results indicate that using high-strength steel and improving the steel ratio can significantly enhance the bearing capacity of the SRC columns. When the slenderness ratio increases dramatically, the bearing capacity of the SRC columns plummets. As the confinement effect of the stirrups on the concrete improves, the utilization ratio of the high-strength steel in the SRC columns increases. Furthermore, the results calculated by AISC360-19(U.S.), EN1994-1-1-2004 (Europe), and JGJ138-2016(China) are too conservative compared with test results. Finally, a modified formula for calculating the bearing capacity of the SRC columns is proposed based on the confinement effect of the stirrups and steel on concrete. The results calculated by the modified formula and the finite element modeling results based on the confinement effect agree well with the test results.

scholarly journals Hysteretic Behavior of Steel Reinforced Concrete Columns Based on Damage Analysis

2019 ◽  
Vol 9 (4) ◽  
pp. 687 ◽  
Author(s):  
Bin Wang ◽  
Guang Huo ◽  
Yongfeng Sun ◽  
Shansuo Zheng
Keyword(s):  
Reinforced Concrete ◽  
Damage Index ◽  
Hysteresis Loops ◽  
Time History ◽  
Hysteretic Behavior ◽  
Loading Path ◽  
Test Results ◽  
Hysteresis Model ◽  
Skeleton Curve ◽  
Steel Reinforced Concrete

With the aim to model the seismic behavior of steel reinforced concrete (SRC) frame columns, in this research, hysteresis and skeleton curves were obtained based on the damage test results of SRC frame columns under low cyclic repeat loading and the hysteretic behavior of the frame columns was further analyzed. Then, the skeleton curve and hysteresis loops were further simplified. The simplified skeleton curve model was obtained through the corresponding feature points obtained by mechanical and regression analysis. The nonlinear combination seismic damage index, which was developed by the test results and can well reflect the effect of the loading path and the number of loading cycle of SRC frame columns, was used to establish the cyclic degradation index. The strength and stiffness degradation rule of the SRC frame columns was analyzed further by considering the effect of the accumulated damage caused by an earthquake. Finally, the hysteresis model of the SRC frame columns was established, and the specific hysteresis rules were given. The validity of the developed hysteresis model was verified by e comparison between the calculated results and the test results. The results showed that the model could describe the hysteresis characteristics of the SRC frame columns under cyclic loading and provide guidance for the elastoplastic time-history analysis of these structures.

scholarly journals Flexural Behavior of Bamboo Reinforced Concrete Beam with Steel Stirrups

2019 ◽  
Vol 8 (4S2) ◽  
pp. 97-99
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Reinforced Concrete Beam ◽  
Flexural Behavior ◽  
Test Results ◽  
Steel Reinforced Concrete ◽  
Beam Design ◽  
Materials Used ◽  
Bamboo Reinforcement

The flexural behavior of concrete beams reinforced with bamboo was studied experimentally. Bamboo was used as the main reinforcement with different bonding materials in place of steel. A nominal mix of M20 grade concrete was adopted for the beam design. The Bamboo surface was treated with common binding materials like Araldite and Bitumen. Araldite and Bitumen are good binding materials used to connect materials like steel, carbon and many different materials. Two specimens were casted with bitumen coating, two specimens were coated with araldite, two specimens were casted without any binder coating and a specimen was casted using normal steel reinforcement. Beams were casted with bamboo reinforcement and cured for 28 days. Deflection and flexural behavior of the beams were monitored. The test results imply that araldite coating in concrete beams with bamboo reinforcement increased the flexural strength to that of bamboo reinforced concrete using bitumen which is lesser strength to that of steel reinforced concrete beam.

Experimental Study on Residual Load Bearing Capacity of SRC Eccentric Columns after Exposure to Fire

2010 ◽  
Vol 163-167 ◽  
pp. 2240-2246 ◽  
Author(s):  
Jun Hua Li ◽  
Yue Feng Tang ◽  
Ming Zhe Liu
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Ultimate Strength ◽  
Room Temperature ◽  
Ultimate Load ◽  
Flexural Rigidity ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Steel Reinforced Concrete

This paper provided three test data pertaining to the mechanical properties of steel reinforced concrete (SRC) eccentric columns after exposure to fire and one comparative test data pertaining to the mechanical properties of steel reinforced concrete columns at room temperature. The influence of eccentricity on failure mode, distortion performance and ultimate load bearing capacity are mainly studied. Test results show that the failure modes of steel reinforced concrete eccentric columns after exposure to fire are similar to that at room temperature. Strain along the section height at mid-span section of eccentric columns before loaded to 90% ultimate load bearing capacity is linearly distributed and well agree with the plane section supposition. After exposure to fire, the flexural rigidity and load bearing capacity of specimens are all declined compared with that at normal temperature. In various loading stages from the initial loading to 80% ultimate strength, the ratio of flexural rigidity of SRC eccentric columns after exposure to fire and at normal temperature is ranged from 0.30 to 0.59. With the same concrete strength and heating condition, the ultimate strength of specimens decreases with the increasing of eccentricity. The ultimate bearing capacity of all specimens at normal room temperature is calculated on the method proposed by Chinese regulation JGJ 138-2001. The compared results of experimental values and calculating values show that the residual load bearing capacity of SRC eccentric columns after exposure to fire is about 69% to 81% of that at room temperature.

scholarly journals Experimental study on damage evaluation of stainless steel–reinforced concrete piers under lateral impact

2020 ◽  
Vol 12 (5) ◽  
pp. 168781402092488
Author(s):  
Bo Wu ◽  
Shixiang Xu
Keyword(s):  
Stainless Steel ◽  
Reinforced Concrete ◽  
Impact Damage ◽  
Test System ◽  
Reinforcement Ratio ◽  
Test Results ◽  
Lateral Impact ◽  
Steel Reinforced Concrete ◽  
Steel Bars ◽  
The Impact

Horizontal impact tests of stainless steel–reinforced concrete piers with different reinforcement ratios at different impact velocities were carried out by using the ultra-high drop weight impact test system. Degree of piers damage after impact was comprehensively analyzed by measuring the acceleration of the impact body, the displacement of the top of the pier specimens, the strain of the steel bars, the rotation of the pier bottom, and the crack development of concrete. The test results showed that under the same impact velocity, with the decrease in reinforcement ratio, the peak acceleration of the impact body, the displacement of the top of pier specimens, the strain of steel bars, and the pier bottom rotation all increase. To a certain extent, increasing the reinforcement ratio of bridge piers can effectively reduce impact damage.

scholarly journals Research on Hysteretic Models for Prestressed and Non-Prestressed Steel Reinforced Concrete Frames

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Huihui Luo ◽  
Kun Wang
Keyword(s):  
Reinforced Concrete ◽  
Slenderness Ratio ◽  
Test Results ◽  
Concrete Frames ◽  
Reinforced Concrete Frame ◽  
Relevant Research ◽  
Steel Reinforced Concrete ◽  
Concrete Frame ◽  
Composite Frame ◽  
Load Displacement

The beam-column fibre model is used to simulate the entire hysteretic process of the prestressed and non-prestressed steel reinforced concrete frame, and the results are compared with the test results. Based on the analysis of a large number of parameters, the hysteretic curve characteristics of this kind of composite frame are discussed, and the load-displacement hysteretic models of single-storey and single-span composite frame are established. The models can comprehensively consider the influence of axial compression ratio and column slenderness ratio and can predict the hysteretic behaviour of this kind of composite frame under horizontal loads. The load-displacement hysteretic models are consistent with the numerical simulation results. Relevant research can provide reference for simplifying the elastic-plastic dynamic analysis of structures.

Long-Term Deformations of Steel-Reinforced Concrete Columns under Sustained Axial Loads

2013 ◽  
Vol 351-352 ◽  
pp. 645-649
Author(s):  
Zhou Yi Chen ◽  
Yang Wang ◽  
Jian Qing Wu
Keyword(s):  
Reinforced Concrete ◽  
Axial Loading ◽  
Test Results ◽  
Axial Loads ◽  
Steel Reinforced Concrete ◽  
Dependent Behavior ◽  
Shrinkage And Creep ◽  
Long Term Behavior ◽  
Creep And Shrinkage

Steel-reinforced concrete (SRC) columns have been widely used over the past few decades. However, very limited research has been conducted on the time-dependent behavior of these columns caused by creep and shrinkage under sustained loading. This paper presents the results of an experimental study of the long-term behavior of short SRC columns under sustained axial loading. Long-term axial deformations due to shrinkage and creep of the concrete were recorded. In analysis of the test results, time analysis of the SRC columns under sustained axial loads using the age-adjusted effective modulus method was proven to be suitable by employing the ACI 209 model for prediction of shrinkage and the CEB-FIP90 model for the prediction of creep.

Axial Bearing Capacity of Steel Reinforced Concrete Short Column with Double Circular Steel Tubes

2013 ◽  
Vol 721 ◽  
pp. 720-725
Author(s):  
Juan Wang ◽  
Jun Hai Zhao ◽  
Sai Wu ◽  
Nan Li
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Relevant Literature ◽  
Steel Tube ◽  
Test Results ◽  
Steel Tubes ◽  
Element Analysis ◽  
Steel Reinforced Concrete ◽  
Short Column ◽  
Good Agreement

Based on the twin shear unified strength theory, analyzing the condition of load for the steel tube and the core-concrete under tri-axial compression, the formula of axial bearing capacity of steel reinforced concrete short column with double circular steel tubes was established and the influencing factors on it were discussed. By the comparison between the results calculated by the formula and the test results, it shows good agreement. Meanwhile, applying the formula to an engineering example, good agreement can be found in the comparison between the calculation in this paper and finite element analysis result in relevant literature. The conclusions can provide a reference for the engineering design.

Nonlinear Analysis on Stainless Steel Reinforced Concrete Columns under Low-Cyclic Load

2012 ◽  
Vol 256-259 ◽  
pp. 588-591
Author(s):  
Guo Xue Zhang ◽  
Chang Wei Wang ◽  
Jia Wei Huang
Keyword(s):  
Stainless Steel ◽  
Reinforced Concrete ◽  
Cyclic Load ◽  
Concrete Columns ◽  
Element Model ◽  
Test Results ◽  
Earthquake Simulation ◽  
Reinforced Concrete Columns ◽  
Static Test ◽  
Steel Reinforced Concrete

In order to study the elastic-plastic mechanics properties of the stainless steel reinforced concrete columns under low-cyclic load, the engineering open-source earthquake simulation system OpenSees is used to carry out the numerical simulation. The comparison between the computed results and the pseudo-static test results shows that the OpenSees may stimulate the mechanical properties of the stainless steel reinforced concrete columns by using the fiber element model, both of the skeleton curves and hysteretic curves are well agreement with the tests results.

Fire Performance of CFST, SRC and RC Frames

2011 ◽  
Vol 99-100 ◽  
pp. 300-303
Author(s):  
Guang Yong Wang ◽  
Xing Qiang Wang ◽  
Guang Wei Liu ◽  
Xiao Yang Liu ◽  
Da Fang Ma
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Failure Mechanism ◽  
Fire Resistance ◽  
Room Temperature ◽  
Steel Tube ◽  
Frame Structures ◽  
Fire Performance ◽  
Steel Reinforced Concrete ◽  
Rc Frames

Failure mechanism and fire resistance comparison of concrete-filled steel tube (CFST) frames, reinforced concrete (RC) frames and steel reinforced concrete (SRC) fames are proposed in this paper when their bearing capacity and rigidity at room temperature are similar. The result shows that the failure mode and failure mechanism of the 3 frame structures are much different, and the SRC frames have the maximum fire resistance.

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