scholarly journals Axial Compressive Behavior of Reinforced Concrete (RC) Columns Incorporating Multi-Walled Carbon Nanotubes and Marble Powder

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 247
Author(s):  
Abdul Jalil Khan ◽  
Liaqat Ali Qureshi ◽  
Muhammad Nasir Ayaz Khan ◽  
Akhtar Gul ◽  
Muhammad Umar ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Main Property ◽  
Concrete Columns ◽  
Sem Analysis ◽  
Multiwalled Carbon ◽  
Reinforced Concrete Columns ◽  
Multi Walled Carbon Nanotubes ◽  
Marble Powder

In this study, Multiwalled Carbon Nanotubes (MWCNTs) and Marble Powder (MP) have been utilized in reinforced concrete columns to assess their structural behavior. The nanotubes from 0.025% to 0.20% and 5% MP by weight of cement were used. The compressive strength of reinforced concrete columns and cubes was analyzed as the main property. The incorporation of MWCNTs and marble powder was able to increase the compressive strength of columns by 72.69% and mortar by 42.45% as compared to reference concrete. The ductility was noted to be improved by 42.04%. The load-deformation and stress-strain behaviors were also analyzed. The Scanning Electron Microscopy (SEM) analysis revealed the formation of a strong compact bridge (90–100 layers), Calcium Silicate Hydrate (C-S-H) gel, evenly dispersion, and bridging effect caused by MWCNTs. The incorporation of 0.20% MWCNTs by weight of cement was recommended to be effectively used as a reinforcing agent in concrete.

scholarly journals Construction of N-M Interaction Diagram for Reinforced Concrete Columns Strengthened with Steel Jackets Using Plastic Stress Distribution Method

2017 ◽  
Vol 3 (10) ◽  
pp. 929
Author(s):  
Mohannad Husain Al-Sherrawi ◽  
Hamza M. Salman
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Stress Distribution ◽  
Concrete Columns ◽  
Concrete Compressive Strength ◽  
Distribution Method ◽  
Reinforced Concrete Columns ◽  
Interaction Diagram ◽  
Steel Angle ◽  
Plastic Stress

No attempts have been made in developing the N-M interaction diagram for reinforced concrete columns strengthened with steel jackets using the plastic stress distribution method. Therefore, this paper presents an analytical model to construct the N-M interaction diagram for reinforced concrete columns strengthened with steel jackets using the plastic stress distribution method after assuming the behavior of strengthened column to be like composite column and including the effects of confinement on concrete compressive strength. The proposed model was compared with experimental results. The comparisons showed that the model is conservative and it reveals the ultimate strength of the strengthened column. A parametric study has been also carried out to investigate the influence of various parameters on the N-M interaction diagram of the strengthened column. These parameters were: dimensions of steel angle, yield stress of the steel angles, concrete compressive strength and the size of the reinforcement bars used in RC columns. The results made clear the effects of these parameters on the N-M interaction diagram, and encouraged the use of the model in preliminary strengthening studies.

scholarly journals Numerical Analysis of Strength Capacity of High-Performance Reinforced Concrete Columns with Varied Parametric Study

2020 ◽  
Vol 14 (1) ◽  
pp. 141-151
Author(s):  
Hadi N. G. Al-Maliki
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Load Capacity ◽  
Axial Loading ◽  
Concrete Columns ◽  
Reinforced Concrete Columns ◽  
Strength Capacity ◽  
The Moment

Introduction: This study includes the analysis of the strength capacity of high performance reinforced concrete columns subjected to concentric axial loading. The main variables are based on the compressive strength of concrete and steel reinforcing ratios. All the columns are fixed, supported by two ends. Methods: This study is based on a calculation done according to ACI Code-318M-2011 equations for columns analysis to evaluate the ultimate strength then applied these load on samples to compare between them by software program Prokon V.3. The comparison is based on reinforcement ratio and moment resistance capacity. Results: The analysis results show that when increasing the main reinforcement with high-performance concrete led, there will be an increased load capacity by about (40 to 215%) and moment resistance capacity by about (35 to 50%) with the same load conditions. According to the analysis of the results, the moment resistance capacity of constant sample value with different reinforcing ratio leads to these resist depending on the load applied, and the concrete compressive strength of columns. Conclusion: Reasonable correlation of the results is demonstrated, which ensured the adequacy of the analysis by test program, both hand calculation and software Prokon.V.3.

Stirrup effects on compressive strength and ductility of confined concrete columns

2013 ◽  
Vol 10 (6) ◽  
pp. 497-506 ◽  
Author(s):  
Jure Radnic ◽  
Radoslav Markic ◽  
Alen Harapin ◽  
Domagoj Matesan ◽  
Goran Baloevic
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Cross Section ◽  
Experimental Testing ◽  
Rectangular Cross Section ◽  
Concrete Columns ◽  
Confined Concrete ◽  
Reinforced Concrete Columns ◽  
Strength And Ductility

The results of experimental testing of stirrup effects on compressive strength and ductility of axially loaded confined reinforced concrete columns of rectangular cross-section are presented. Effects of different concrete strengths, different stirrup bar diameters and different stirrup spacing on column's bearing capacity and ductility have been researched.

Experimental and numerical investigations on the size effect of moderate high-strength reinforced concrete columns under small-eccentric compression

2017 ◽  
Vol 27 (5) ◽  
pp. 657-685 ◽  
Author(s):  
Liu Jin ◽  
Zixing Ding ◽  
Dong Li ◽  
Xiuli Du
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Size Effect ◽  
Compressive Loading ◽  
High Strength ◽  
Concrete Columns ◽  
Failure Behavior ◽  
Reinforced Concrete Columns ◽  
Failure Patterns ◽  
Softening Behavior

The paper deals with an experimental investigation and numerical simulation of moderate high-strength reinforced concrete (RC) columns subjected to a small-eccentric compressive loading ( e0 = 0.25 h0). A series of tests on the behavior of 12 geometrically similar moderate high-strength reinforced concrete columns with two different stirrups ratios (i.e., 0% and 0.66%) were conducted. The maximum structural size of the square reinforced concrete columns was 800 mm. A 2D mesoscale method for the simulation of the behavior of reinforced concrete columns was established. The numerical tests on the reinforced concrete columns with larger stirrup ratios (1.2% and 2.4%) were carried out complementarily, based on the fact that the simulation results were consistent with the available test observations. The failure patterns, the nominal compressive stress–strain relationships, the nominal compressive strength, and the post-peak softening behavior of the reinforced concrete columns were studied. Furthermore, the influence of stirrups on failure behavior and size effect of the reinforced concrete columns was revealed. One can conclude that (1) the size effect exists in the nominal compressive strength of the eccentrically loaded high-strength reinforced concrete columns with the four different stirrup ratios; (2) comparison of the present test results and the “size effect law” proposed by Bažant shows good agreement; (3) the presence of stirrups improves the nominal strengths, makes the failure of columns less brittle, and weakens the size effect; and (4) the proposed mesoscale numerical method is capable of describing the mechanical behavior of eccentrically loaded reinforced concrete columns.

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