scholarly journals Carbonic Gas Randomness Effect on Reinforced Concrete Carbonation

Engineering ◽  
2012 ◽  
Vol 04 (01) ◽  
pp. 6-10 ◽  
Author(s):  
Azhar Badaoui ◽  
M’hammed Badaoui ◽  
Fattoum Kharchi
Keyword(s):  
Reinforced Concrete ◽  
Concrete Carbonation ◽  
Carbonic Gas

MEASURING CRACK WIDTH IN RC AND R/FRC TIES THROUGHT LASER SCANNER

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Nicola Critelli ◽  
Alessandro Cesetti ◽  
Alessandro P. Fantilli ◽  
Francesco Tondolo
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Laser Scanner ◽  
Chloride Ion ◽  
Fiber Reinforced Concrete ◽  
Fundamental Parameter ◽  
Concrete Carbonation ◽  
Rc Structure ◽  
Chloride Ion Penetration ◽  
Conoscopic Holography

Durability of reinforced concrete (RC) structure is strictly connected to the capacity of concrete mass to protect the embedded reinforcement from corrosion. As cracks are almost inevitable, crack width is a fundamental parameter that needs to be controlled during the serviceability stage of RC members. In fact, not only the direct ingress of aggressive agents, such as oxygen and water, is a function of crack width, but also concrete carbonation and the chloride ion penetration are accelerated by the presence of wide cracks. Accordingly, the aim of present research project is to assess the width by using a new system, based on the optical conoscopic holography. It provides the non-contact measure of crack profile, taken at the end of each loading cycle, in ties subjected to sets of repeated loads. Both in plain and fiber-reinforced concrete (FRC), more than one crack width can be measured for the same crack.

Prediction of durability of structural concrete in aggressive exposures

2018 ◽  
Author(s):  
Сергей Леонович ◽  
Sergey Leonovich ◽  
Валентин Доркин ◽  
Valentin Dorkin ◽  
Оксана Чернякевич ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Building Materials ◽  
Limit State ◽  
Concrete Structures ◽  
Life Cycles ◽  
Reinforced Concrete Structures ◽  
Concrete Durability ◽  
Concrete Carbonation ◽  
Corrosion Of Steel

The monograph is devoted to the prediction of the longevity of reinforced concrete structures, the destruction of which is associated with corrosion of steel reinforcement caused by chloride aggression or concrete carbonation. On the basis of a comprehensive analysis of models for calculating the service life of structures and experimental data, preference is given to the mathematical model Dura Crete. Life cycles for the main degradation processes in concrete and reinforcement, periods of initiation and propagation of corrosion are considered. Particular attention is paid to the influence of environmental factors and the quality of concrete on the kinetics of chloride penetration and movement of the carbonization front. Formulated limit state design reinforced concrete durability in chloride attacks and carbonation. The basic provisions of the method of calculating the durability of reinforced concrete structures, based on the use of the reliability coefficient for the service life. The practical assessment of service life of reinforced concrete elements taking into account stochastic processes in concrete and reinforcement is made. Verification of the model reliability is performed. For all those interested in the issues of building materials and processes occurring in them.

Effect of concrete carbonation on natural frequency of reinforced concrete beams

2016 ◽  
Vol 20 (3) ◽  
pp. 316-330 ◽  
Author(s):  
Liye Zhang ◽  
Limin Sun
Keyword(s):  
Reinforced Concrete ◽  
Natural Frequency ◽  
Natural Frequencies ◽  
Concrete Beams ◽  
Physicochemical Process ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Accelerated Carbonation ◽  
Concrete Carbonation ◽  
Damage In Concrete

We carried out an experimental investigation to study the influence of concrete carbonation on the natural frequency of simply supported reinforced concrete beams. A total of 10 reinforced concrete test beams and 12 concrete-carbonation test specimens were subjected to different accelerated carbonation stages for 0, 7, 14, 21, and 28 days. Modal tests were performed on reinforced concrete test beams after the accelerated carbonation stages. In order to reduce the effect of other factors on the modal tests, constant temperature, relative humidity, and boundary conditions of the test beams were maintained in the experimental process. The experimental results show a trend of the natural frequencies of reinforced concrete test beams to decrease with the increase in concrete-carbonation depths. With statistical analyses of experimental data, this study established the relationship between concrete-carbonation depths and natural frequencies. Fitting lines for the drop in natural frequencies and carbonation depths are obtained for the first four modal frequencies. Based on the analysis of the physicochemical processes of concrete carbonation, the main reason behind the drop in natural frequencies is the increase in mass after concrete carbonation. The percentage composition of increase in mass after complete carbonation is obtained based on the analysis of the physicochemical process. This analysis demonstrates part of the reason for the drop in natural frequencies and proves that the experimental results are reliable and credible. This study provides further insight into the use of modal parameters to assess damage in concrete structures in structural health monitoring.

Strengthening of the Frame Structure at the Timisoreana Brewery, Romania

2010 ◽  
pp. 57-80
Author(s):  
Corneliu Bob ◽  
Sorin Dan ◽  
Catalin Badea ◽  
Aurelian Gruin ◽  
Liana Iures
Keyword(s):  
Reinforced Concrete ◽  
Load Resistance ◽  
Concrete Cover ◽  
Frame Structure ◽  
Reinforced Concrete Structure ◽  
Existing Structures ◽  
Concrete Carbonation ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Lateral Load Resistance

<p>Many structures built in Romania before 1970 were designed for gravity loads with inadequate lateral load resistance because earlier codes specified lower levels of seismic loads. Some of these structures are still in service beyond their design life. Also, some deterioration was observed in existing structures due to the actions of different hazard factors. This paper presents the case study of a brewery with reinforced concrete framed structure of five storeys and a tower of nine storeys, which has been assessed and strengthened. The brewery and the tower were built in 1961 and an extension in 1971. An assessment performed in 1999 showed up local damages at slabs, main girders, secondary beams, and columns; concrete carbonation; concrete cover spalled over a large surface; complete corrosion of many stirrups and deep corrosion of main reinforcement; and some broken reinforcement. Such damage was caused by salt solution, CO2, relative humidity RH 80%, and temperatures over 40◦C. Also, inadequate longitudinal reinforcement was deduced≈ from the structural analysis. The initial design, done in 1960, was according to the Romanian codes of that time with provisions at low seismic actions. The structural system weakness is due to present-day high seismic actions. The rehabilitation of the reinforced concrete structure was performed by jacketing with reinforced concrete for the main and secondary beams and columns. In 2003, due to continuous operation and subsequent damage of the structure, a new assessment was required. It was found that some beams and one column were characterized by inadequate main and shear reinforcement as well as corrosion of many stirrups at beams. The strengthening solution adopted was based on carbon fibre reinforced polymer composites for beams and column.</p>

Steel Fiber Reinforced Concrete Carbonation Simulation Research

2011 ◽  
Vol 243-249 ◽  
pp. 108-111 ◽  
Author(s):  
Yuan Yao Miao ◽  
Di Tao Niu ◽  
Yan Wang
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
Steel Fiber ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Reinforced Concrete Structure ◽  
Steel Fiber Reinforced Concrete ◽  
Carbonation Depth ◽  
Simulation Research ◽  
Concrete Carbonation

Durability of concrete structure due to carbonation problem has attracted worldwide attention. By studying on the performance of steel fiber reinforced concrete carbonation, simulations CO2corrosion environment was simulated. The impacts of the change law of carbonation depth of steel fiber reinforced concrete with water cement ratio (0.35,0.45,0.55), as well as steel fiber content (0%, 0.5%, 1.0%, 1.5% , 2.0%), pouring surface and age, on concrete carbonation depth were studied. Steel fiber reinforced concrete carbonation performance improvement role was analyzed. Thus, providing a experimental basis that can be used in the design and analysis of the durability of steel fiber reinforced concrete structure.

scholarly journals Probabilistic Analysis of Reinforced Concrete Carbonation Depth

2013 ◽  
Vol 04 (03) ◽  
pp. 205-215
Author(s):  
Azhar Badaoui ◽  
M’hammed Badaoui ◽  
Fattoum Kharchi
Keyword(s):  
Reinforced Concrete ◽  
Probabilistic Analysis ◽  
Carbonation Depth ◽  
Concrete Carbonation

Researches on Concrete Carbonation

2013 ◽  
Vol 357-360 ◽  
pp. 737-742
Author(s):  
Zhong Yuan Li ◽  
Zhu Jun Wang
Keyword(s):  
Reinforced Concrete ◽  
Steel Corrosion ◽  
Co2 Concentration ◽  
Reinforced Concrete Buildings ◽  
Engineering Community ◽  
Concrete Buildings ◽  
Concrete Carbonation ◽  
Core Issues

The cause and prevention of concrete carbonation are core issues in the engineering community. With the improvement of the global CO2 concentration, more and more reinforced concrete buildings are faced with the problems of carbonation acceleration and following threats of steel corrosion which will heavily undermine the safety and durability of R.C. structures. The article from three major aspects, Concrete carbonation mechanism, causes of carbonation and carbonation influences, reviews and summarizes the current researches on carbonation and proposes valuable suggestions.

scholarly journals Estimation of Concrete Carbonation Depth Considering Multiple Influencing Factors on the Deterioration of Durability for Reinforced Concrete Structures

2016 ◽  
Vol 2016 ◽  
pp. 1-18 ◽  
Author(s):  
Hae-Chang Cho ◽  
Hyunjin Ju ◽  
Jae-Yuel Oh ◽  
Kyung Jin Lee ◽  
Kyung Won Hahm ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Concrete Member ◽  
Carbonation Depth ◽  
Inference System ◽  
Concrete Carbonation ◽  
Reinforced Concrete Member ◽  
Inspection Data ◽  
Adaptive Neurofuzzy Inference System

While the durability of concrete structures is greatly influenced by many factors, previous studies typically considered only a single durability deterioration factor. In addition, these studies mostly conducted their experiments inside the laboratory, and it is extremely hard to find any case in which data were obtained from field inspection. Accordingly, this study proposed an Adaptive Neurofuzzy Inference System (ANFIS) algorithm that can estimate the carbonation depth of a reinforced concrete member, in which combined deterioration has been reflected based on the data obtained from field inspections of 9 buildings. The proposed ANFIS algorithm closely estimated the carbonation depths, and it is considered that, with further inspection data, a higher accuracy would be achieved. Thus, it is expected to be used very effectively for durability estimation of a building of which the inspection is performed periodically.

scholarly journals Visible Corrosion Damage in Carbonated Reinforced Concrete

2021 ◽  
Vol 65 (2) ◽  
pp. 129-148
Author(s):  
Alina Lahdensivu ◽  
Jukka Lahdensivu
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Damage ◽  
Research Data ◽  
Cover Depth ◽  
Concrete Panels ◽  
Concrete Carbonation ◽  
Minimum Cover ◽  
Localized Damage

Abstract This study discusses visible corrosion damage due to carbonation in concrete balconies and facades. The focus of the study was to find out how the age of the structure, cover depth of concrete, carbonation coefficient, capillarity of concrete and the climate affect visible corrosion damage. The research data consist of condition investigation reports of existing concrete balconies and facades built between 1948 and 1996. Balcony slabs and brushed painted facades were the most prone to visible corrosion damage. None of the researched panels met the required minimum cover depth of reinforcement even at the time of construction. However, most of the visible damage on the database was localized damage and there was not much visible corrosion damage. The carbonation coefficient of balconies was higher than the carbonation coefficient of facades. Brushed painted facade panels had clearly higher carbonation coefficient than other facade panels. The carbonation coefficient was considerably lower on white concrete panels compared to other panel types. When capillarity of concrete raises, the carbonation rate of concrete increases slightly. However, no correlation can be seen. The capillarity of concrete and the carbonation rate of concrete had a major range.

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