scholarly journals Carbonation Resistance Classes of Concretes

2021 ◽  
Vol 10 (1) ◽  
pp. 50-66
Author(s):  
Cristinel Moraru ◽  
Adelina Apostu ◽  
Dan Georgescu
Keyword(s):  
Reinforced Concrete ◽  
Surface Defects ◽  
Major Change ◽  
Concrete Cover ◽  
Concrete Bridges ◽  
Design Stage ◽  
Cement Stone ◽  
Carbonation Reaction ◽  
Carbonation Resistance ◽  
Bridge Structures

Abstract Concrete carbonation is a phenomenon that occurs by the penetration into the cement stone of CO2 present in the atmosphere. The phenomenon occurs in the presence of water in which CO2 dissolves, forming carbonate ions, which in turn react with calcium ions in the pores of the concrete, resulting in calcium carbonate (calcite). The diffusion of CO2 occurs through pores and surface defects, it thus penetrates deeper into the concrete and the carbonation reaction can occur at a greater depth, eventually exceeding the thickness of the cover, causing corrosion of the reinforcement. [1] In the case of reinforced concrete bridges, corrosion induced by carbonation of concrete is one of the main causes of degradation. Thus, in the design stage of the reinforced concrete bridge structures, the inevitable process of carbonation of the concrete must be taken into account, in the design of the durability, by calculating the thickness of the concrete cover layer. This article aims to present the concept of carbonation resistance class, which will be a major change in the standard based on which the thickness of the concrete cover for reinforcement will be determined. This presentation is made in the context of the European performance approach to durability. In this sense, an analysis of the experimental results obtained in research on concrete prepared with different types of cements, carried out in collaboration with the laboratory of the Reinforced Concrete Structures Department, within the Technical University of Civil Engineering Bucharest. Proposals for classification in the carbonation resistance classes for concretes prepared with two types of cements are also presented.

Fatigue Behavior of Corroded Reinforced Concrete Beams-a Review

2011 ◽  
Vol 94-96 ◽  
pp. 1523-1526
Author(s):  
Shi Bin Li ◽  
Hong Wei Tang ◽  
Xin Wang
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Fatigue Behavior ◽  
Concrete Bridges ◽  
Reinforced Concrete Beams ◽  
Rc Structures ◽  
Concrete Members ◽  
Bridge Structures ◽  
Traffic Volumes ◽  
Chloride Attack

Reinforced concrete (RC) structures are widely used in civil engineering for their merits. A good-quality concrete provides a highly alkaline environment that forms a passive film on reinforcement surface, preventing steel bars from corroding. Due to chloride attack or concrete carbonization, corrosion of embedded reinforcement in concrete members is common for RC structures. Much importance should be attached to the fatigue of corroded concrete bridges because they bear not only static loads but also alternate loads. Followed along with the aging of bridge structures, the increase of traffic volumes, the augment of vehicle loads as well as the deterioration of service environment, many corroded concrete bridges are urgently needed security appraisal and residual fatigue life forecast. Fatigue of corroded RC beams is a key problem for the existing corrosion-damaged concrete bridges. But the interrelated research was little. Based on the most new study information, the production on fatigue of corroded concrete beams was listed and analyzed, and the problems on fatigue of corroded concrete beams were indicated.

Advanced Seismic Countermeasures for Concrete Bridges by Using Polymer in Japan

2011 ◽  
Vol 466 ◽  
pp. 207-214
Author(s):  
Makoto Kawakami ◽  
Fujio Omata ◽  
Jun’ichi Iketani ◽  
Satoru Matsuoka
Keyword(s):  
Reinforced Concrete ◽  
Epoxy Resin ◽  
Polymer Composites ◽  
Strong Earthquake ◽  
Steel Plate ◽  
Concrete Columns ◽  
Concrete Bridges ◽  
Civil Infrastructures ◽  
Bridge Structures ◽  
Bullet Train

Modern infrastructures such as viaducts, bullet train (Shinkansen) elevated tracks, and subway facilities in addition to houses and buildings were greatly damaged at the Hyogo-Ken Nanbu Earthquake that hit heavily populated urban cities in 1995. As a learning lesson from this earthquake, seismic countermeasures for civil infrastructures have been rapidly reviewed and implemented. In this study, damage of bridge structures due to this strong earthquake was reported and the current effective seismic retrofit of concrete columns and bridge-falling prevention systems by use of concrete polymer composites in Japan were introduced. Two main seismic countermeasure methods were introduced and discussed: Steel plate and fiber jacketing methods for existing reinforced concrete piers/columns, and unseating devices for bridge-falling prevention. Both these countermeasures use epoxy resin as essential component.

scholarly journals The Cover Depth Effect on Corrosion-Induced Deterioration of Reinforced Concrete Focusing on Water Penetration: Field Survey and Laboratory Study

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3478
Author(s):  
Shingo Asamoto ◽  
Junya Sato ◽  
Shinichiro Okazaki ◽  
Pang-jo Chun ◽  
Raktipong Sahamitmongkol ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Laboratory Study ◽  
Numerical Study ◽  
Steel Corrosion ◽  
Concrete Cover ◽  
Concrete Bridges ◽  
Water Penetration ◽  
Depth Effect ◽  
Cover Depth ◽  
Oxygen Penetration

Reinforced concrete bridges were visually surveyed in Japan, Thailand, and Vietnam to study the deterioration caused by internal steel corrosion under different climates, focusing on the concrete cover depth. Spalling or cracking arising from corrosion is likely where water is supplied. According to prior studies and our surveys, a concrete cover depth of more than 40 mm was found to prevent spalling, regardless of environmental conditions and structure age. Because water supply at steel is a key corrosion factor, it was hypothesised that under natural conditions, the water penetration in concrete would remain at a depth of approximately 40 mm. Our laboratory study examined water penetration under drying and wetting conditions. The results also suggested that under periodic rainfall conditions, the threshold of water penetration was not exceeded. The numerical study indicated maximum moisture evaporation to facilitate oxygen diffusion occurred at a depth of approximately 30–40 mm unless the concrete was exposed to continuous drying for more than one month. It was experimentally and numerically concluded that an adequate cover depth of greater than 40 mm could inhibit moisture and oxygen penetration at the steel, which supported the survey findings of cover depth effect on a high resistance to corrosion-induced deterioration despite an increase in service life.

scholarly journals ASSESSMENT OF TECHNICAL STATE AND DESIGN OF RECONSTRUCTION OF THE SMALL BRIDGE OF THE SLOVINSKY SYSTEM

2020 ◽  
pp. 52-65
Author(s):  
V.H. Kvasha ◽  
◽  
A.Ya. Muryn ◽  
L.V. Salyichuk ◽  
◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Concrete Cover ◽  
Concrete Bridges ◽  
Technical State ◽  
Design Standards ◽  
Reinforced Concrete Bridges ◽  
Current Design ◽  
Design Solutions ◽  
Bridge Reconstruction ◽  
Former Ussr

Abstract. In the 1950s and 1960s of the 20th century a lot of one- and two-span bridges with a span of 4-6 m were built on public roads on the territory of the former USSR. The paper describes the features of the design and construction of small four-hinged reinforced concrete bridges on lightweight supports of engineer Slovinsky system. The experience of surveying small bridges shows that in the context of a limited funding, compared to other types of bridges, maintenance and operation of these bridges does not get enough attention. There are relatively low material losses from their destruction and it is possible to restore them fairly easily. Therefore, many of them have a large number of defects and are in a poor physical condition. The purpose of the work is to draw attention of owners to the problems of small bridges using a specific example, as well as to present effective constructive solutions for the reconstruction of a small four-hinge bridge. These design solutions are developed on the basis of the research and development in Lviv National Polytechnic University and include the use of a reinforced concrete cover slab. The slab has been frequently used in other bridge reconstruction projects and proved its technical and economic efficiency in practice. The article gives characteristics of the bridge, the technical state of its structures, the main defects and damages, as well as the characteristics of the stream and its influence on the condition of the bridge. The design solutions for widening and strengthening the small bridge of the Slovinsky system can provide operational performance and consumer properties in accordance with the requirements of the current design standards for new bridges. These standards are able to ensure the service life of the reconstructed bridge.

Fracture Analysis of Reinforced Concrete Bridge Structures with Account of Concrete Cracking under Steel Corrosion

2013 ◽  
Vol 831 ◽  
pp. 364-369 ◽  
Author(s):  
Andrey V. Benin ◽  
Artem S. Semenov ◽  
S.G. Semenov
Keyword(s):  
Reinforced Concrete ◽  
Steel Corrosion ◽  
Concrete Cover ◽  
Concrete Bridge ◽  
Bond Slip ◽  
Reinforced Concrete Bridge ◽  
Initiation And Propagation ◽  
Bridge Structures ◽  
Concrete Blocks ◽  
Fracture Processes

A direct 3D finite element (FE) modeling of fracture processes in reinforced concrete bridge structures is considered with account of the macrocracks initiation and propagation, real geometry of reinforcing elements, discontinuity in the bond-slip behavior, using elastic-plastic-damage constitutive equations for concrete. The comparison of obtained FE results with experimental data is presented and discussed for the pulling ribbed bars out of concrete blocks, the spalling of concrete cover at the automobile bridge and cracking of ballastless deck at the railway bridge.

Analisa Pola Kegagalan Balok Beton Menggunakan GFRP Bar Tanpa Selimut Beton

2020 ◽  
Vol 24 (1) ◽  
pp. 11-16
Author(s):  
Saddam - Husein ◽  
Rudy Djamaluddin ◽  
Rita Irmawaty ◽  
Kusnadi Kusnadi
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Concrete Cover ◽  
Steel Reinforcement ◽  
Fiber Reinforced Polymer ◽  
Mode Analysis ◽  
Flexural Capacity ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Gfrp Bar

SADDAM HUSEIN. Analisa Pola Kegagalan Balok Beton Menggunakan GFRP Bar Tanpa Selimut Beton (dibimbing oleh Rudi Djamaluddin dan Rita Irmawaty) Struktur beton bertulang yang menggunakan tulangan baja pada daerah korosif, menjadi rawan terhadap kerusakan atau penurunan kekuatannya akibat korosi.Korosi pada tulangan baja merupakan salah satu faktor penyebab menurunnya kekuatan struktur beton bertulang. Salah satu material yang dikembangkan mengatasi korosi adalah penggunaan material tulangan GFRP (Glass Fiber Reinforced Polymer). Penelitian ini bertujuan untuk menganalisa kapasitas lentur dan pola kegagalan balok beton tanpa selimut dengan menggunakan material tulangan GFRP bar.   Desain penelitian merupakan eksperimental laboratorium dengan rekapitulasi sebanyak 6 sampel yang terdiri dari 2 Balok beton menggunakan tulangan baja dengan selimut beton, 2 balok beton menggunakan tulangan GFRP bar dengan selimut beton, 2 balok beton menggunakan GFRP bar tanpa selimut beton. Metode pengujian dilakukan dengan dengan pengujian lentur statik monotonik dan Analisis data menggunakan uji kondisi retak awal dan kondisi ultimit.   Hasil penelitian ini menunjukkan bahwa kapasitas lentur pada balok dengan tulangan GFRP bar lebih besar dibandingkan dengan balok tulangan baja dan mampu meningkatkan kapasitas lentur balok dalam menahan beban sebesar 39.76 %, pola kegagalan beton yang terjadi pada balok tulangan baja mengalami kegagalan lentur tekan ditandai dengan retakan yang terjadi pada sisi tertekan dan membentuk retakan tegak dengan sumbu netral beton yang tertekan, sedangkan pada balok beton tulangan GFRP tanpa selimut mengalami kegagalan keruntuhan tekan geser dengan kondisi tulangan berdeformasi (bi-linear) dengan retak miring dan secara tiba-tiba menjalar menuju sumbu netral beton yang tertekan sehingga terjadilah keruntuhan secara tiba-tiba.     SADDAM HUSEIN.Failure mode analysis of concrete Beams Using GFRP rebar Without concrete cover (supervised by Rudi Djamaluddin and Rita Irmawaty)   Reinforced concrete that uses rebar steel in corrosive areas, are prone to damage or decreased strength due to corrosion. Corrosion in the steel reinforcement is one of the factors that decreasing strength of reinforced concrete. One of the materials developed to overcome corrosion is the use of GFRP (Glass Fiber Reinforced Polymer) reinforcement material. This study aims to analyze the flexural capacity and failure mode of concrete beams without concrete cover using material GFRP bar as reinforcement.   The research design was an experimental laboratory with a recapitulation of 6 samples consisting of 2 beams using steel reinforcement with concrete cover.2 concrete beams using reinforcement GFRP bar with concrete cover, 2 beams using GFRP bars without concrete cover. The  research method uses the monotonic static flexure and analyzing the data using the initial crack condition and ultimate conditions test.   The results of the research indicate the flexural capacity of the beams with GFRP bar reinforcement is higher than steel reinforcement beams and can increase 39.76% of the flexural capacity of the beams in holding loads , the failure mode analysis occurs in steel reinforcing beam experiences compressive failure. Failure was characterized  by cracks that occur on the depressing side and form an upright crack with the neutral axis of the compressed concrete, whereas in GFRP reinforced concrete beams without concrete cover, failure of shear compression with conditions of deformed reinforcement (bi-linear) with sloping cracks and suddenly spread towards the neutral axis of the compressed concrete so that there was a sudden collapse.

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