Accounting for steel rebar effect on resistivity profiles in view of reinforced concrete structure survey

2019 ◽  
Vol 223 ◽  
pp. 898-909 ◽  
Author(s):  
Marie Antoinette Alhajj ◽  
Sérgio Palma-Lopes ◽  
Géraldine Villain
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
Reinforced Concrete Structure ◽  
Steel Rebar

scholarly journals Alternative methodology for linear polarization resistance assessment of reinforced concrete structure

2018 ◽  
Vol 199 ◽  
pp. 06009 ◽  
Author(s):  
Gabriel Samson ◽  
Fabrice Deby ◽  
Jean-Luc Garciaz ◽  
Jean-Louis Perrin
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Current Density ◽  
Linear Polarization ◽  
Concrete Structure ◽  
Polarization Resistance ◽  
Concrete Cover ◽  
Reinforced Concrete Structure ◽  
Linear Polarization Resistance ◽  
Steel Rebar

For reinforced concrete structures, several corrosion detection methods exist: concrete resistivity, half-cell potential or linear polarization resistance (LPR) measurement. The LPR value can be linked to the corrosion rate thanks the Stern-Geary equation if strong hypotheses are made. Existing commercial devices use a guard ring to canalize the current on specific steel rebar area and assume that the steel rebar is uniformly polarized. However, recent works reveal that the top part of the steel rebar, right under the counter electrode, is the most polarized point. The particular point is referred as the point of interest (PI). This works belongs to the DIAMOND project which aims to produce a new corrosion rate measurement device. Comsol® software was used to model the influence of concrete cover, resistivity and injected current on the current density at the PI. Moreover, a significant influence of the steel rebars diameter was also demonstrated. Two types of abacus are built. The first one links to polarization measured on the surface to the polarization on the rebar at the PI. The second links the ratio between the current density at the PI and the density of injected current to concrete cover and steel rebar diameter. The Stern-Geary equation can now be used at the PI without using the approximation of a uniformly polarized rebar. The corrosion state of reinforced concrete structure can be controlled more precisely. The methodology is then applied on two concrete slabs in which three metal bars are embedded at different concrete covers. The first slab is prepared with ordinary concrete while the second contain chloride to artificially activate the corrosion process. The results reveal that the rebars embedded on the first slab are not corroding (icorr ≤0.2 μΑ/cm2) while the second rebar are corroding (icorr>0.2 μΑ/cm2).

Test and Study on Impact of Corrosion on Bond Force between Steel and Concrete

2010 ◽  
Vol 36 ◽  
pp. 176-181
Author(s):  
Xian Feng He ◽  
Shou Gang Zhao ◽  
Yuan Bao Leng
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Concrete Structure ◽  
Steel Corrosion ◽  
Reinforced Concrete Structure ◽  
Bond Force ◽  
Steel Bars ◽  
Protection Layer ◽  
Corrosion Of Steel ◽  
The Impact

The corrosion of steel will have a bad impact on the safety of reinforced concrete structure. In severe cases, it may even be disastrous. In order to understand the impact of steel corrosion on the structure, tests are carried out to study corrosion and expansion rules of steel bars as well as the impact rules of corrosion on bond force between steel and concrete. The results show that wet and salty environment will result in steel corrosion; relatively minor corrosion will not cause expansion cracks of protection layers; when steel rust to a certain extent, it will cause cracks along the protection layer; when there exists minor corrosion in steel and the protection layer does not have expansion cracks, the bond force is still large and rapidly decreases as the corrosion rate increases.

Assessment of the aftertreatment quality of concrete

2021 ◽  
Author(s):  
Lisa Ptacek ◽  
Alfred Strauss ◽  
Clémence Bos ◽  
Martin Peyerl
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
Test Methods ◽  
Reinforced Concrete Structure ◽  
Process Step ◽  
Simple Tool ◽  
Lack Of Control ◽  
Complex Construction

<p>The curing of concrete is extremely important for the durability of a reinforced concrete structure. In practice, due to the complex construction processes, the very limited phases and the lack of control, aftertreatment is often neglected by executing companies. Hence infrastructure operators are therefore very interested in having a robust, simple tool that enables aftertreatment to be easily checked and, as a result, to convey the importance of this process step to the client. In the project presented here, classic and novel test methods are presented and discussed, as well as their suitability for the detection of the aftertreatment quality on laboratory samples and subsequently on some real structures.</p>

scholarly journals Numerical Analysis of a Moderate Fire inside a Segment of a Subway Station

2018 ◽  
Vol 8 (11) ◽  
pp. 2116 ◽  
Author(s):  
Rodrigo Díaz ◽  
Hui Wang ◽  
Herbert Mang ◽  
Yong Yuan ◽  
Bernhard Pichler
Keyword(s):  
Reinforced Concrete ◽  
Surface Temperature ◽  
Concrete Structure ◽  
Fire Test ◽  
Material Behavior ◽  
Sensitivity Analyses ◽  
Subway Station ◽  
Elastic Model ◽  
Reinforced Concrete Structure ◽  
Actual Distribution

A 1:4 scaled fire test of a segment of a subway station is analyzed by means of three-dimensional Finite Element simulations. The first 30 min of the test are considered to be representative of a moderate fire. Numerical sensitivity analyses are performed. As regards the thermal boundary conditions, a spatially uniform surface temperature history and three different piecewise uniform surface temperature histories are used. As regards the material behavior of concrete, a temperature-independent linear-elastic model and a temperature-dependent elasto-plastic model are used. Heat transfer within the reinforced concrete structure is simulated first. The computed temperature evolutions serve as input for thermomechanical simulations of the fire test. Numerical results are compared with experimental measurements. It is concluded that three sources of uncertainties render the numerical simulation of fire tests challenging: possible damage of the structure prior to testing, the actual distribution of the surface temperature during the test and the time-dependent high-temperature behavior of concrete. In addition, the simulations underline that even a moderate fire represents a severe load case, threatening the integrity of the reinforced concrete structure. Tensile cracking is likely to happen at the inaccessible outer surface of the underground structure. Thus, careful inspection is recommended even after non-catastrophic fires.

Research Progress on Reinforced Concrete Laminated Slab in China

2012 ◽  
Vol 174-177 ◽  
pp. 263-267
Author(s):  
Ming Li ◽  
Zhe Zhe Sun ◽  
Wei Jian Zhao ◽  
Yong Liu
Keyword(s):  
Reinforced Concrete ◽  
Experimental Research ◽  
Concrete Structure ◽  
Early Stage ◽  
Research Progress ◽  
Horizontal Load ◽  
Reinforced Concrete Structure ◽  
Research Results ◽  
Load Carrying ◽  
New Generation

The development of new generation prefabricated reinforced concrete structure is still at an early stage in China. Reinforced concrete laminated slab, as an important horizontal load carrying member, is paid much attention to in research. Based on the research results about it in China, the progress of which is summarized, including the form, characteristics and experimental research of sandwich laminated slab, anti-ribbed laminated slab, and hollow laminated slab etc. Finally, the further research is prospected.

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