Innovative test method for the investigation of carbonation and chloride ingress on reinforced concrete components exposed to mechanical loads

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.

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Development of fiber reinforced concrete repair materials

Canadian Journal of Civil Engineering ◽

10.1139/l05-093 ◽

2006 ◽

Vol 33 (2) ◽

pp. 126-133 ◽

Cited By ~ 8

Author(s):

N Banthia ◽

R Gupta ◽

S Mindess

Keyword(s):

British Columbia ◽

Reinforced Concrete ◽

Cellulose Fiber ◽

Fiber Reinforced Concrete ◽

Test Method ◽

Fiber Reinforced ◽

Parking Garage ◽

Shrinkage Cracking ◽

University Of British Columbia ◽

Repair Materials

Early age shrinkage cracking remains a critical concern for cement-based repairs and overlays. Fibers mitigate such cracking, but no standardized technique of assessing the performance of a given fiber exists. Recently, a novel technique of making such an assessment was developed at The University of British Columbia (UBC). In this test method, currently being balloted through the ASTM, an overlay of fiber reinforced concrete (FRC) material to be tested is cast directly on a fully matured sub-base with protuberances, and the entire assembly is subjected to controlled drying. Cracking in the overlay is then monitored and characterized. The technique was recently employed to develop "crack-free" overlay materials for two repair sites. One was a parking garage in Downtown Vancouver, British Columbia, and the other was the plaza deck at The UBC Aquatic Center. For the parking garage, a carbon fiber reinforced concrete and for the plaza deck, a cellulose fiber reinforced concrete were developed. Both overlays were instrumented with strain sensors and data were monitored over the Internet.Key words: fiber reinforced concrete, shrinkage cracking, strain monitoring, carbon fibers, cellulose fibers.

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Detection of Reinforcement Corrosion in Reinforced Concrete Structures by Potential Mapping: Theory and Practice

International Journal of Corrosion ◽

10.1155/2018/3027825 ◽

2018 ◽

Vol 2018 ◽

pp. 1-6

Author(s):

Gino Ebell ◽

Andreas Burkert ◽

Jürgen Mietz

Keyword(s):

Reinforced Concrete ◽

Influencing Factors ◽

Stress Measurement ◽

Concrete Structures ◽

German Society ◽

Theory And Practice ◽

Test Method ◽

Reinforced Concrete Structures ◽

Reinforcing Steel ◽

Potential Mapping

Electrochemical potential mapping according to guideline B3 of DGZfP (German Society for Nondestructive Testing) is a recognized technique for the localization of corroding reinforcing steels. In reinforced concrete structures the measured potentials are not necessarily directly linked to the corrosion likelihood of the reinforcing steel. The measured values may be significantly affected, different from, e.g., stress measurement, by different influences on the potential formation at the phase boundary metal/concrete itself as well as the acquisition procedure. Due to the complexity of influencing factors there is a risk that the results are misinterpreted. Therefore, in a training concept firstly the theoretical basics of the test method should be imparted. Then, frequently occurring practical situations of various influencing factors will be made accessible to the participants by a model object specially designed for this purpose. The aim is to impart profound knowledge concerning the characteristics of potential mapping for detecting corrosion of reinforcing steel in order to apply this technique in practice as reliable and economical test method.

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Full-Field Displacement and Strain Measurement: Application of Digital Image Correlation to Reinforcement Corrosion Induced Concrete Fracture and Cover Cracking

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.738-739.889 ◽

2015 ◽

Vol 738-739 ◽

pp. 889-892

Author(s):

Qiang Li ◽

Hong Fa Yu ◽

Jing Tong

Keyword(s):

Reinforced Concrete ◽

Steel Corrosion ◽

Test Method ◽

Image Correlation ◽

Concrete Fracture ◽

Reinforcement Corrosion ◽

Full Field ◽

Rc Structures ◽

Whole Process ◽

Cover Cracking

Cracking of the cover concrete due to steel corrosion is considered as one of the major issues of durability of reinforced concrete (RC) structures. This paper tentatively studies the feasibility of DIC to reinforcement corrosion induced concrete fracture and cover cracking measurement. Advantages and limitations of DIC-based non-contact full-field measurement for corrosion induced concrete fracture and cover cracking are discussed. Drawbacks in this test need improvement are pointed out and test method for further study of whole process of simulating the real reinforced concrete cracking is put forward.

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The Corrosion Probability and Flexural Strength of an RC Beam under Chloride Ingress Considering the Randomness of Temperature and Humidity

Materials ◽

10.3390/ma13102260 ◽

2020 ◽

Vol 13 (10) ◽

pp. 2260

Author(s):

Sen Pang ◽

Ming-kai Yu ◽

Hong-guang Zhu ◽

Cheng Yi

Keyword(s):

Reinforced Concrete ◽

Standard Deviation ◽

Relative Humidity ◽

Flexural Strength ◽

Early Stage ◽

Load Capacity ◽

Chloride Ingress ◽

Concrete Cracking ◽

Beam Design ◽

Temperature And Humidity

The load capacity of reinforced concrete structure will decrease by chloride ingress in coastal region. In this paper, the corrosion probability and flexural strength of a typical reinforced concrete beam design under the influence of temperature and humidity was obtained by the Monte Carlo method. The relationship between flexural strength, temperature, relative humidity, and geometric parameters was established. The annual average temperature and relative humidity were treated as random variables together with the geometric size and concrete compressive strength. The corrosion probability and flexural strength in a wave splashing zone, coastal atmospheric zone, and offshore atmospheric zone were calculated. The results show that the corrosion probabilities of the three regions are obviously different. When the standard deviation of temperature is less than 1.5 °C, the temperature can be treated as a constant in the calculation of the concrete cracking probability in the wave splashing zone. A binary logistic regression formula was given to predict whether the randomness of temperature and humidity should be considered in the offshore atmospheric zone. When the standard deviation of the temperature is less than 1 °C, the temperature randomness has no significant effect on the flexural strength of beams in the wave splashing zone. The flexural strength distribution conforms to the normal distribution in the early stage of service and the Weibull distribution after concrete cracking.

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Effect of Cu, Cr, S Doped TiO2 for Transparent Plastic Bar Reinforced Concrete

Applied Sciences ◽

10.3390/app10207334 ◽

2020 ◽

Vol 10 (20) ◽

pp. 7334

Author(s):

Seung-Hoon Seo ◽

Byoung-Il Kim

Keyword(s):

Absorption Spectrum ◽

Reinforced Concrete ◽

Visible Light ◽

High Performance Concrete ◽

Test Method ◽

Visible Absorption Spectrum ◽

Nox Removal ◽

Transparent Plastic ◽

Visible Absorption ◽

Uv Visible

In this study, after firing and powdering Cu, Cr, and S with NP-400 TiO2, an NOx removal rate test was performed according to the ISO test method to analyze the photocatalytic reactivity in visible light. The distribution of the photocatalyst and visible light reactivity on the surface of the test specimen were confirmed through SEM (Scanning electron microscope), EDS (Energy dispersive spectroscopy), XRD (X-ray diffraction), UV-visible absorption spectrum and energy band gap tests. The flowability of UHPC (Ultra high performance concrete) slightly decreased due to the increase in the photocatalyst mixing rate, but both J-Ring and L-Box test results showed that there is no problem when concrete is placed. As a result of SEM and EDS tests, good microstructure and peak values were confirmed in the test specimens doped with Cu, and as a result of the XRD test, anatase and rutile peaks were confirmed in the Cu, Cr, and S specimens. In the UV-visible absorption spectrum analysis, it was confirmed that only the specimen doped with Cu maintains a high absorption power of 0.8 up to 700 nm, and the inherent band gaps are reduced to 2.9 eV, thereby increasing the possibility of reaction in visible light. Finally, as a result of the NOx removal test by the ISO test method, about 15.8% was removed for 5 h in the specimen doped with Cu, and the removal efficiency is estimated to be possible up to about 25% when applied with the TPBRC (transparent plastic bar reinforced concrete).

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