scholarly journals Volumetric Deformations and Crack Control in Reinforced Concrete Structures

2021 ◽  
Author(s):  
Mahmut Acarcan
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Structural Integrity ◽  
Concrete Structures ◽  
Prediction Equation ◽  
Reinforcement Ratio ◽  
Strain History ◽  
Reinforced Concrete Structures ◽  
Limited Information ◽  
Reinforcement Design

Restraint temperature and shrinkage strains are one of the major reasons for cracking of reinforced concrete. Cracking of concrete reduces structural integrity, initiates or accelerates deterioration mechanisms, causes serviceability problems and may raise aesthetical concerns. Particularly for liquid retaining structures, cracks are vital for structural functionality. Measures must be take to prevent or control crack. In most cases, it may not be feasible to prevent crack formation, but crack width can be controlled by providing sufficient amount of reinforcement. Design guides provide limited information on adequate reinforcement design for temperature and shrinkage cracks in reinforced concrete structures. The Finite Element Method(FEM) was used in order to investigate the crack risk, magnitude of crack width, and adequate reinforcement ratio for controlling cracks within the design specifications. In order to find the thermal and shrinkage strains effect during early ages, computer simulations was performed for hardening concrete. Using the computer program ABAQUS/6.4, incremental numerical analysis technique was implemented that provided realistic simulation of stress/strain history. Considering an appropriate value for thermal and shrinkage strains, a parametric study was carried out to estimate the reinforcement ratio for fixed base walls. The crack width was estimated based on the calculated steel stress and the ACI 318-02 crack prediction equation. With consideration of ACI 350-01 specification for allowable crack width, the required amount of reinforcement ratio for various wall dimensions was recommended.

scholarly journals Volumetric Deformations and Crack Control in Reinforced Concrete Structures

2021 ◽  
Author(s):  
Mahmut Acarcan
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Structural Integrity ◽  
Concrete Structures ◽  
Prediction Equation ◽  
Reinforcement Ratio ◽  
Strain History ◽  
Reinforced Concrete Structures ◽  
Limited Information ◽  
Reinforcement Design

Restraint temperature and shrinkage strains are one of the major reasons for cracking of reinforced concrete. Cracking of concrete reduces structural integrity, initiates or accelerates deterioration mechanisms, causes serviceability problems and may raise aesthetical concerns. Particularly for liquid retaining structures, cracks are vital for structural functionality. Measures must be take to prevent or control crack. In most cases, it may not be feasible to prevent crack formation, but crack width can be controlled by providing sufficient amount of reinforcement. Design guides provide limited information on adequate reinforcement design for temperature and shrinkage cracks in reinforced concrete structures. The Finite Element Method(FEM) was used in order to investigate the crack risk, magnitude of crack width, and adequate reinforcement ratio for controlling cracks within the design specifications. In order to find the thermal and shrinkage strains effect during early ages, computer simulations was performed for hardening concrete. Using the computer program ABAQUS/6.4, incremental numerical analysis technique was implemented that provided realistic simulation of stress/strain history. Considering an appropriate value for thermal and shrinkage strains, a parametric study was carried out to estimate the reinforcement ratio for fixed base walls. The crack width was estimated based on the calculated steel stress and the ACI 318-02 crack prediction equation. With consideration of ACI 350-01 specification for allowable crack width, the required amount of reinforcement ratio for various wall dimensions was recommended.

Damage of Reinforced Concrete Structures due to Steel Corrosion

2015 ◽  
Vol 1111 ◽  
pp. 187-192
Author(s):  
Corina Sosdean ◽  
Liviu Marsavina ◽  
Geert de Schutter
Keyword(s):  
Reinforced Concrete ◽  
Building Materials ◽  
Structural Integrity ◽  
Colorimetric Method ◽  
Concrete Structures ◽  
Steel Corrosion ◽  
Degradation Process ◽  
Reinforced Concrete Structures ◽  
Chloride Ingress ◽  
Rc Structures

Reinforced concrete (RC) became one of the most widely used modern building materials. In the last decades a great interest has been shown in studying reinforcement corrosion as it became one of the main factors of degradation and loss of structural integrity of RC structures. The degradation process is accelerated in the case of RC structures situated in aggressive environments like marine environments or subjected to de-icing salts. In this paper it is shown how steel corrosion of the embedded rebars occurs and how this affects the service life of reinforced concrete structures. Also, an experimental study regarding the combined effect of carbonation and chloride ingress was realized. Samples with and without rebars were drilled from a RC slab which was stored in the laboratory for two years. Non-steady state migration tests were realized in order to determine the chloride profile, while the carbonation depth was measured using the colorimetric method based on phenolphthalein spraying. It was concluded that carbonation has a significant effect on chloride ingress, increasing it.

scholarly journals Effects of Tension Reinforcement Ratio on Ductility of Mid-Rise Reinforced Concrete Structures

2018 ◽  
Vol 1 (1) ◽  
pp. 702-708
Author(s):  
Onur Onat ◽  
Burak Yön
Keyword(s):  
Reinforced Concrete ◽  
Failure Mode ◽  
Concrete Structures ◽  
Reinforcement Ratio ◽  
Reinforced Concrete Structures ◽  
Rc Structures ◽  
Beam Elements ◽  
First Case ◽  
Rc Structure ◽  
Determine Effect

Failure mode of reinforced concrete (RC) structures are classified according to tension reinforcement ratio of beam elements. To determine effect of tension reinforcement ratio on performance of RC structure, two planar RC structure were selected. One of them is 5 stories other of them is 7 stories. Two different concrete class, C20 and C25, were considered for analysis. Three tension reinforcement combinations were considered, three different tension reinforcement ratios were used. First case is the ratio of the tension reinforcement is lower than that of the compression reinforcement, second case is the ratio of the tension reinforcement is equal to the ratio of the compression reinforcement and third case is the ratio of the tensile reinforcement is higher than the compression reinforcement.

scholarly journals Experimental study of the influence of crack width due to corrosion behaviour using different measurement methods and different exposures

2019 ◽  
Vol 289 ◽  
pp. 08005
Author(s):  
Martin Schneider ◽  
Georg Gardener
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Corrosion Behaviour ◽  
Concrete Strength ◽  
Concrete Structures ◽  
Chloride Ions ◽  
Reinforced Concrete Structures ◽  
Reinforcing Steel ◽  
Surface Corrosion ◽  
Potential Mapping

Corrosion of reinforcing steel has a great influence in reducing the lifetime of concrete structures; Carbonation of the concrete pore solution causes surface corrosion on the steel and diffusion of chloride ions through the capillary system of the concrete cover causes pitting corrosion on the steel surface. Corrosion of metals is highly dependent on the environmental conditions. Exposure to chloride ions can be critical to the service life of reinforced concrete structures. The durability of reinforced concrete structures exposed to deicing salt or marine environments can be affected by impact of chloride ions. Detection methods for the rate of corrosion of non-destructive and destructive procedures were analysed. The potential mapping applied on the concrete surface was discussed as a standard method for corrosion detection and will be explained in detail including the application boundaries of the method. It is assumed that the corrosion behaviour of reinforcing steel depends on crack widths. To analyse that, 8 coated and 8 uncoated test samples with different concrete strength classes were used. The concrete objects were exposed to a 3% sodium chloride solution. The corrosion behaviour of reinforcing steel is analysed by using potential mapping with different reference electrodes (Ag/AgCl and Cu/CuSO4). The results show a significant correlation between crack size and protection system on the surface. The maximum crack width with a low indication of corrosion was found to be 0.1 mm.

scholarly journals The Mechanical Properties of Centrifuged Concrete in Reinforced Concrete Structures

2020 ◽  
Vol 10 (10) ◽  
pp. 3570
Author(s):  
Romualdas Kliukas ◽  
Ona Lukoševičienė ◽  
Arūnas Jaras ◽  
Bronius Jonaitis
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Concrete Strength ◽  
Concrete Structures ◽  
High Strength ◽  
Reinforcement Ratio ◽  
Transverse Reinforcement ◽  
Reinforced Concrete Structures ◽  
Test Results ◽  
Moduli Of Elasticity

This article explores the influence of transverse reinforcement (spiral) and high-strength longitudinal reinforcements on the physical-mechanical properties of centrifuged annular cross-section elements of concrete. The test results of almost 200 reinforced, and over 100 control elements are summarizing in this article. The longitudinal reinforcement ratio of samples produced in the laboratory and factory varied from 1.0% to 6.0%; the transverse reinforcement ratio varied from 0.25% to 1.25%; the pitch of spirals varied from 100 mm to 40 mm and the concrete strength varied from 25 MPa to 60 MPa. Experimental relationships of coefficients for concrete strength, moduli of elasticity and limits of the longitudinal strain of centrifuged concrete in reinforced concrete structures in short-term concentrically compression were proposed.

Prediction of Crack Width of Chloride Contaminated Reinforced Concrete Structures

2006 ◽  
Vol 302-303 ◽  
pp. 610-617
Author(s):  
Jia Jin Zheng ◽  
Xin Zhu Zhou ◽  
Shi Lang Xu
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Corrosion Rate ◽  
Crack Width ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Cover Depth ◽  
Steel Bar ◽  
Bar Diameter ◽  
Chloride Contaminated

Crack width is a significant parameter for assessing service life of reinforced concrete structures in chloride-laden environments. Corrosion-induced concrete cracking is a predominant causal factor influencing premature degradation of reinforced concrete structures, incurring considerable costs for repairs and inconvenience to the public due to interruptions. This gives rise to the need for accurate prediction of crack width in order to achieve cost-effectiveness in maintaining serviceability of concrete structures. It is in this regard that the present paper attempts to develop a quasi-brittle mechanical model to predict crack width of chloride contaminated concrete structures. Assuming that cracks be smeared uniformly in all directions and concrete be a quasi-brittle material, the displacement and stress in a concrete cover, before and after surface cracking, were derived respectively in an analytical manner. Crack width, as a function of the cover depth, steel bar diameter, corrosion rate and time, was then determined. Finally, the analysis results were verified by comparing the solution with the experimental results. The effects of the cover depth, steel bar diameter and corrosion rate on the service life were discussed in detail.

Calculation of the Minimum Reinforcement for Limitation of Crack Width According to Change of National Annex for ČSN EN 1992-1-1

2015 ◽  
Vol 1106 ◽  
pp. 217-220
Author(s):  
Jiří Šmejkal ◽  
Jaroslav Procházka
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Concrete Structures ◽  
Maximum Distance ◽  
Reinforced Concrete Structures ◽  
Optimal Amount ◽  
Minimum Reinforcement ◽  
Concrete Elements

Design of minimum reinforcement for concrete elements with regard to width of cracks is important for consumptions of steel. Optimal amount of reinforcement shall ensure that cracks, which are typical for reinforced concrete structures, will be small that the serviceability and durability will be not influenced. One of most important parameter for crack width is the maximum distance between cracks. The information connecting with various procedures for design and minimum reinforcement with regard to width of cracks are given in this article.

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