Crack control for reinforced and prestressed concrete structures

1980 ◽  
Vol 7 (3) ◽  
pp. 466-476
Author(s):  
H. A. Falkner
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Crack Width ◽  
Crack Formation ◽  
Concrete Structures ◽  
Expansion Joints ◽  
Crack Control ◽  
Total Length ◽  
Maximum Crack

The principal relationship between concrete and rebars when cracks form in reinforced concrete (RC) and prestressed concrete (PC) structures is presented. Mainly for better understanding, crack formation in concrete is compared with that of other materials such as wood or soil.Cracks in RC and PC structures are almost unavoidable and are more often caused by restraint forces than by loads. Cracks are harmless for serviceability and durability if crack width is limited to hair cracks up to 0.2 or 0.3 mm. Although it has been proved that cracks up to 0.4 mm wide do not increase corrosion of the embedded steel, engineers have to strive to limit crack width primarily to get a good appearance from concrete structures.References are given to completed RC and PC structures having a maximum crack width of less than 0.2 mm and structures without expansion joints up to a total length of 140 m.

scholarly journals Analysis of Crack Width Development in Reinforced Concrete Beams

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3043
Author(s):  
Barbara Goszczyńska ◽  
Wiesław Trąmpczyński ◽  
Justyna Tworzewska
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Crack Formation ◽  
Concrete Beams ◽  
Concrete Structures ◽  
Diagnostic Methods ◽  
Reinforced Concrete Beams ◽  
Reinforced Concrete Structures ◽  
Maximum Crack ◽  
Concrete Elements

The reliability and durability of reinforced concrete structures depend on the amount of concrete cracking. The risk associated with cracks generates a need for diagnostic methods for the evaluation of reinforced concrete structures. This paper presents the results of a study of 10 single-span reinforced concrete beams to follow the process of crack formation and changes in their width. The beams were loaded to failure with two forces in a monotonic manner with unloading and in a cyclic manner. Continuous observation of the crack formation process was provided by the digital image correlation system. The simplified method for estimating the maximum crack width is proposed. The presented results confirmed the stochastic character of the process of crack formation and development. The maximum crack widths calculated on the basis of the proposed formula were on the safe side in relation to those calculated according to Eurocode 2. It was also confirmed that the distances between cracks do not depend on the loading manner. Hence the density function describing the distribution of distances between cracks can be used to assess the condition of reinforced concrete elements. The research has also shown the suitability of the DIC system (ARAMIS) for testing concrete elements.

Numerical Modeling of Time-Dependent Deformations of Concrete at 3D Analysis of Structures

2020 ◽  
Author(s):  
◽  
Ante Džolan
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Concrete Structures ◽  
Real Life ◽  
Nonlinear Behavior ◽  
3D Analysis ◽  
Actual Behavior ◽  
Realistic Simulation ◽  
Highly Nonlinear ◽  
Prestressed Structures

Concrete is a material with highly nonlinear behavior. In parallel, there are numerous secondary effects in concrete, such as aging, shrinkage, and creep, which further complicate the realistic simulation of reinforced concrete and prestressed concrete structures. In modern times, due to bolder construction, increasing spans and high rising construction, the need for realistic simulation of the behavior of concrete structures under conditions of various types of loads is becoming more pronounced. On the other hand, models with a small number of real-life parameters that can describe the actual behavior of concrete as accurately as possible are necessary. One such model, the previously developed model Precon 3D, which is based on a small number of parameters and can very well describe the behavior of concrete, reinforced concrete and prestressed structures for short-term static loads was taken as the basis for this work. Through this work, the numerical model Precon 3D has been upgraded with a model for following the behavior of concrete during time, i.e. the model has been upgraded with a model of creep and shrinkage of concrete, which is necessary for following the behavior of prestressed structures. The developed software has been tested against several experimental examples from the literature, with a very good match between numerical and experimental results.

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.

Research on Safety Evaluation System of Reinforced Concrete Structures Based on the Blasting Damage

2014 ◽  
Vol 1065-1069 ◽  
pp. 1217-1221
Author(s):  
Guo Quan Zhu ◽  
Jun Lin Tao ◽  
Xiao Ling Liu
Keyword(s):  
Reinforced Concrete ◽  
Evaluation System ◽  
Concrete Structures ◽  
Safety Evaluation ◽  
Security Level ◽  
Reinforced Concrete Structures ◽  
Element Analysis ◽  
Database Technology ◽  
Maximum Crack ◽  
Evaluation Platform

The safety of reinforced concrete structures will be impacted by the explosions. Using the calculations result of finite element analysis software, combining with database technology, a security level evaluation platform of blasting damage in reinforced concrete structures is established. The platform assesses the safety of damaged structure from the remaining bearing capacity, maximum crack width and maximum deflection, etc. It gives the security level from different aspects of the structure and the integrated security level, and repair advice.

Research on Influences of the Coarse Aggregate Size on the Cracks of the Reinforced Beam

2012 ◽  
Vol 503-504 ◽  
pp. 832-836
Author(s):  
Hong Quan Sun ◽  
Jun Ding
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Coarse Aggregate ◽  
Concrete Beams ◽  
Fractal Theory ◽  
Aggregate Size ◽  
Reinforced Concrete Beams ◽  
Static Loads ◽  
Reinforced Beams ◽  
Maximum Crack

This paper gives the influences of the coarse aggregate size on the cracks of the beam with different aggregate sizes under static loads. The coarse aggregate sizes are ranked into three classes: small size (4.75mm ~ 19mm), big size (19mm ~ 37.5mm) and mixed size (4.75mm ~ 37.5mm). The developments of cracks of three reinforced concrete beams with the different of coarse aggregate sizes under the static loads are researched. The results show that under the action of the same loads, The reinforced concrete beams with the big aggregate size and mixed aggregate size have almost the same maximum crack width, while the maximum crack width of the beam with small aggregate size is less than formers. Using fractal theory, the fractal dimension of the cracks is studied. The result shows that the aggregate sizes have significant effect to the cracks on the reinforced beams.

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