Performance Based Specifications for Durability of Mass Concrete Blocks Subjected to Harsh Arabian Gulf Marine Environment

2016 ◽  
Vol 711 ◽  
pp. 444-452
Author(s):  
K. Rahman Muhammad ◽  
Al Omran Zaki ◽  
Ibrahim Mohammed ◽  
Al Nahdi Fahad ◽  
S. Barry Mohammed
Keyword(s):  
Service Life ◽  
Arabian Gulf ◽  
Concrete Structures ◽  
Experimental Investigations ◽  
Eastern Region ◽  
Mass Concrete ◽  
Reinforcing Steel ◽  
Concrete Blocks ◽  
Durability Performance

Concrete structures in the Eastern region of Saudi Arabia are exposed to the harsh Arabian Gulf environment, and they suffer from deterioration due to accelerated corrosion of the reinforcing steel resulting in reduced service life. The service life of reinforced concrete structures in this environment is strongly affected by the quality of concrete. The resistances of concrete to chloride penetration, the chloride threshold for corrosion initiation and corrosion rate of the reinforcing steel are critical in ensuring long-term durability of concrete structures. In order to ensure that the concrete functions in the harsh environment for which it is expected to meet the service life requirement, the concrete must be designed for durability performance. A prescriptive concrete specification emphasizing on limits on mix parameters is generally ineffective for durability issues. A performance based specification based on concrete quality represented by durability indices and compliance criteria measured on cast-in-place concrete provides a framework for the contractor and ready-mix concrete supplier to produce a structure meeting the stipulated service life by the client. This paper presents the results of experimental investigations conducted for mass-concrete blocks used in the quay walls off the coastline on a reclaimed land. For long-term durability, a concrete mix in which 50% and 70% of cement was replaced by ground blast furnace slag was used to cater for the durability performance requirements.

Durability Modeling for Enhancing the Service Life of a Building Constructed on a Reclaimed Land in the Sea

2016 ◽  
Vol 711 ◽  
pp. 622-629
Author(s):  
K. Rahman Muhammad ◽  
Ibrahim Mohammed ◽  
Al Omran Zaki ◽  
S. Barry Mohammed ◽  
Al Nahdi Fahad
Keyword(s):  
Service Life ◽  
Corrosion Inhibitor ◽  
Arabian Gulf ◽  
Strength Properties ◽  
Experimental Program ◽  
Experimental Investigations ◽  
Eastern Region ◽  
Reclaimed Land ◽  
Green Concrete ◽  
Concrete Mix

In reinforced concrete structures constructed on the coastline of the hypersaline Arabian Gulf water, corrosion of reinforcing steel causes cracking, delamination and spalling of concrete, within a time span of a few years. The King Abdullah Civic Center (KACC), being constructed on a reclaimed land off the coastline in the Eastern region of Saudi Arabia, is a major complex with wharves, quay walls, and breakwater and commercial buildings. To ensure the durability of buildings in the harsh marine environment and to provide a minimum service life of 35 years, a concrete mix in which 70% of Portland cement is replaced by granulated ground blast furnace slag (GGBFS) was recommended based on durability modeling conducted using the software STADIUM®. Concrete with 70% GGBFS provides for the dual objective of achieving a green concrete and an enhanced service life of the building. Based on durability modelling it was concluded that corrosion inhibitor should be used preferably in the concrete. A detailed experimental program was conducted to assess the durability and strength properties of the 70% GGBFS concrete, with and without corrosion inhibitor. This paper presents the results of experimental investigations and durability modeling conducted for the project. A 70% GGBFS concrete mix without corrosion inhibitor was adopted for the raft foundation and subsequently for the entire building to make it a green concrete building.

New Composite Materials that Reduce the Effect of Reinforcement Corrosion

2013 ◽  
Vol 837 ◽  
pp. 265-270 ◽  
Author(s):  
Vasile Constantinescu ◽  
Gheorghe Veniamin Bogus ◽  
Rares George Taran ◽  
Ioan Carcea
Keyword(s):  
Carbon Dioxide ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Service Life ◽  
Concrete Structures ◽  
Reinforcing Steel ◽  
Reinforcement Corrosion ◽  
Corrosion Initiation ◽  
Deicing Salts ◽  
The World

Concrete is a complex material of construction that enables the high compressive strength of natural stone to be sed in any configuration. In tension, however, concrete can be no stronger than the bond between the cured cement and the surfaces of the aggregate. This is generally much lower than the compressive strength of the concrete. Concrete is therefore frequently reinforced, usually with steel. When a system of steel bars or a steel mesh is incorporated in the concrete structure in such a way that the steel can support most of the tensile stresses and leave the immediately surrounding concrete comparatively free of tensile stress, then the complex is known as reinforced concrete. Corrosion of reinforcing steel in concrete leads to the premature failure of many structures exposed to harsh environments. Rust products form on the bar, expanding its volume and creating stress in the surrounding concrete. This leads to cracking and spalling, both of which can severely reduce the service life and strength of a member. Corrosion of reinforcing steel in concrete structures is one of the most expensive problems facing civil engineers in the world. The structural integrity of many bridges, overpasses, parking garages, and other concrete structures has been impaired by corrosion, and repairs are urgently required to ensure public safety. Corrosion-induced deterioration of reinforced concrete can be modelled in terms of three component steps: (1) time for corrosion initiation; (2) time, subsequent to corrosion initiation, for appearance of a crack on the external concrete surface (crack propagation); and (3) time for surface cracks to progress into further damage and develop into spalls, to the point where the functional service life, is reached. The two most common causes of reinforcement corrosion are: (i) localized breakdown of the passive film on the steel by chloride ions and (ii) general breakdown of passivity by neutralization of the concrete, predominantly by reaction with atmospheric carbon dioxide. Sound concrete is an ideal environment for steel but the increased use of deicing salts and the increased concentration of carbon dioxide in modern environments principally due to industrial pollution, has resulted in corrosion of the rebar becoming the primary cause of failure of this material. The scale of this problem has reached alarming proportions in various parts of the world. Corrosion in reinforced concrete structures is causing deterioration of our infrastructure. Structures in or near marine environments and transportation structures on which deicing salts are used are especially vulnerable. A widely promoted method for repairing damaged structures or for protecting structures in corrosive environments is the application of fiber-reinforced composite wraps over the surface of the structures elements.

scholarly journals Investigation of the relationship between the strength limit and the long time fatigue of steel reinforcements of reinforced concrete structures

2021 ◽  
pp. 28-40
Author(s):  
Denys Chernyshev ◽  
Yulia Makarenko ◽  
Tetiana Khomutetska ◽  
Valeriy Makarenko
Keyword(s):  
Reinforced Concrete ◽  
Crack Resistance ◽  
Hydrogen Content ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Reinforcing Steel ◽  
Term Operation ◽  
Strength Limit

The results of experimental studies have shown a strong effect of diffusion hydrogen on the static and cyclic parameters of crack resistance of reinforcing steel. It was found that with increasing flooding, especially when the hydrogen content exceeds 5 cm3/100g, both static strength and long-term strength (fatigue) decrease sharply. Moreover, these areas of hydrogen solution in reinforcing steel are characterized by a viscous nature of fracture, while for heavily flooded reinforcement (from 5 to 12 cm3/100g) is characterized by brittle fracture by the mechanism of microcracking in the hardened (martensite or troostite structure). The analysis of the obtained experimental results allowed to determine the optimal hydrogen content in the reinforcing steel (3…5 cm3/100g), the excess of which can cause a decrease in the crack resistance of the reinforcement during long-term operation, especially in corrosive environments. The mechanism of hydrogen influence on crack resistance of metal at static and alternating loading which consists in diffusion and dislocation movement of hydrogen in structure of a reinforcing core that as a result that causes strong flooding of steel and its embrittlement is offered. It is established that carbon and low-alloy sieves, which are characterized by ferritic-pearlitic and sorbitol structure provide high resistance, especially to long-term fatigue, and the transition to steels with a structure of martensite or tempered (transient structure of bainite) structure of bainite sharply reduces reinforcing steel, which makes it impossible to use in the manufacture of reinforcement involved in reinforced concrete structures designed for long-term operation (more than 50…60 years). Thus, the obtained diagram can be recommended to designers of reinforced concrete structures for hydraulic purposes, as it greatly facilitates the reasonable choice of reinforcement in the development of reinforced concrete structures for responsible and long-term use.

The Experimental Study on Fatigue Properties of CFRP Reinforced Concrete Beam

2011 ◽  
Vol 383-390 ◽  
pp. 3157-3161
Author(s):  
Zi Qi Li ◽  
Yan Yan Fan
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Service Life ◽  
Concrete Beam ◽  
Concrete Structures ◽  
Reinforced Concrete Beam ◽  
Fatigue Performance ◽  
Fatigue Properties ◽  
Experimental Basis

Based on the research of CFRP reinforced concrete beam , this article indicates that CFRP can improve greatly the fatigue performance of damage concrete beam, prolong its service life , and provide the experimental basis for long-term fatigue properties of CFRP concrete structures.

scholarly journals Modelling of Deterioration Effects on Concrete Structures

10.14311/344 ◽  
2002 ◽  
Vol 42 (3) ◽  
Author(s):  
B. Teplý
Keyword(s):  
Service Life ◽  
Probabilistic Approach ◽  
Concrete Structures ◽  
Analytical Models ◽  
Reinforcing Steel

In order to predict the service life of concrete structures models for deterioration effects are needed. This paper has the form of a survey, listing and describing such analytical models, namely carbonation of concrete, ingress of chlorides, corrosion of reinforcing steel and prestressing tendons. The probabilistic approach is applied.

scholarly journals Service Life Prediction of Concrete Structure Using Life-365 Software

2021 ◽  
Vol 12 (2) ◽  
pp. 1816-1826
Author(s):  
A. Deiveegan, Et. al.
Keyword(s):  
Service Life ◽  
Concrete Structure ◽  
Concrete Structures ◽  
High Strength ◽  
Vital Role ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Global Concern ◽  
Peak Value

The performances of repaired concrete structures continue to be a major global concern. This is the improvement in repairing materials and method, several repaired concrete structures still fail, leading to costly and time-consuming. This study was conducted to assess the effect of long-term chloride penetration as well as the effect of fly ash, water-cement ratio, and inhibitor on concrete structures to predict its Service life to obtained high strength durable concrete. The water-cement ratio played a vital role, as the water-cement ratio is reducing to get more service life of the concrete and at the value of 0.5, it seems that the peak value of service life of the concrete structure. In this paper, it is generally finding the service life of a concrete structure by reviewing the previous researches and by using Software Life-365.

Modeling of Chloride Penetration in Surface Treated Concrete

2008 ◽  
Vol 385-387 ◽  
pp. 765-768
Author(s):  
In Seok Yoon
Keyword(s):  
Cost Effectiveness ◽  
Service Life ◽  
Surface Treatment ◽  
Concrete Structures ◽  
Chloride Penetration ◽  
Treatment System ◽  
Chloride Diffusion ◽  
Maintenance Strategies ◽  
Marine Concrete ◽  
Durability Performance

The surface treatment system is one of the best options to extend the service life of marine concrete in terms of cost effectiveness versus durability performance. In order to establish rational maintenance strategies for surface treated concrete structures, however, it is necessary to define how to quantify and how to optimize the performance of the surface treatment system. The solution could be obtained from the prediction of chloride in surface treated concrete. In this study, theoretical solution to predict the behavior of chloride diffusion in surface treated concrete is constructed.

scholarly journals RELIABILITY OF REINFORCED CONCRETE STRUCTURES TAKING INTO ACCOUNT THE CONCRETE CREEP FACTOR

2021 ◽  
Vol 3 (6) ◽  
pp. 35-43
Author(s):  
V. Pshenichkina ◽  
B. Gricenko ◽  
A. Gluhov ◽  
Babovich Miodrag
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Concrete Strength ◽  
Concrete Structures ◽  
Ambient Air ◽  
Statistical Characteristics ◽  
Reinforced Concrete Structures ◽  
Concrete Creep ◽  
Wide Range

In the process of inspection of reinforced concrete structures being in long-term service, deflections of beams and slabs beyond the standard values are often detected, which is attributable to concrete creep occurring in the case of the early dismantling of shuttering. At the same time, any visual signs of their reduced load-bearing capacity are absent. Taking into account the high degree of uncertainty of the factors influencing the long-term strains of the concrete, the safe service life of such structures can vary within a rather wide range, and its actual value can be assessed only through probabilistic methods of the reliability theory. The paper presents the results of the investigation of the influence of concrete creep caused by the early dismantling of the shuttering on the reliability of prefabricated reinforced concrete floor beams of a three-storey building. The data obtained through the instrumental verification of the mechanical characteristics of the beam materials and their deformed state were used for design modelling. The authors carried out the probabilistic creep analysis of the beam through the method of statistical modelling taking into account the variability of concrete strength for various values of the relative humidity of the ambient air and the age of concrete at the moment of the load application. The statistical characteristics of the stress-strain modulus and the beam deflection values with various levels of probability were obtained. Due to con-crete creep, the safety analysis showed a 2,4 times reduction in the beam reliability index at the service life of a structure of 70 years.

Improvement Of Curvilinear Diagrams Of Concrete Deformation

2019 ◽  
pp. 99-104
Keyword(s):  
Reinforced Concrete ◽  
Peak Load ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Deformation Model ◽  
Reinforced Concrete Structures ◽  
Significant Difference ◽  
Deformation Diagrams

Problems when calculating reinforced concrete structures based on the concrete deformation under compression diagram, which is presented both in Russian and foreign regulatory documents on the design of concrete and reinforced concrete structures are considered. The correctness of their compliance for all classes of concrete remains very approximate, especially a significant difference occurs when using Euronorm due to the different shape and sizes of the samples. At present, there are no methodical recommendations for determining the ultimate relative deformations of concrete under axial compression and the construction of curvilinear deformation diagrams, which leads to limited experimental data and, as a result, does not make it possible to enter more detailed ultimate strain values into domestic standards. The results of experimental studies to determine the ultimate relative deformations of concrete under compression for different classes of concrete, which allowed to make analytical dependences for the evaluation of the ultimate relative deformations and description of curvilinear deformation diagrams, are presented. The article discusses various options for using the deformation model to assess the stress-strain state of the structure, it is concluded that it is necessary to use not only the finite values of the ultimate deformations, but also their intermediate values. This requires reliable diagrams "s–e” for all classes of concrete. The difficulties of measuring deformations in concrete subjected to peak load, corresponding to the prismatic strength, as well as main cracks that appeared under conditions of long-term step loading are highlighted. Variants of more accurate measurements are proposed. Development and implementation of the new standard GOST "Concretes. Methods for determination of complete diagrams" on the basis of the developed method for obtaining complete diagrams of concrete deformation under compression for the evaluation of ultimate deformability of concrete under compression are necessary.

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