scholarly journals Diffusion of chloride from seawater into the concrete analysis: a literature review on implemented approaches

2021 ◽  
Vol 930 (1) ◽  
pp. 012015
Author(s):  
Y S Ariningsih ◽  
D Nuralinah ◽  
A W W Saputra
Keyword(s):  
Analytical Methods ◽  
Coastal Region ◽  
Chloride Ions ◽  
Chloride Diffusion ◽  
Offshore Platforms ◽  
Destructive Testing ◽  
Existing Structures ◽  
Complex Process ◽  
Simple Equations ◽  
Strength And Durability

Abstract Infrastructures near the sea, such as ports, offshore platforms, bridges, and coastal buildings, are affected by seawater due to the coastal region. Chloride, contained in seawater, causes a decrease in the strength and durability of the concrete. Some researchers have published a paper on analyzing the penetration of chloride ions into concrete under different coastal environments and predicted chloride diffusion in concrete with computational modeling. This paper aims to review the existing literature related to various laboratory work tests and analytical methods in evaluating the diffusion of chloride from seawater into concrete. A set of forty papers were collected and reviewed that were published from 2011 until 2020 for studying. The review showed that chloride diffusion was a complex process and affected by many factors such as material properties, curing time, immersion/exposure time, and environmental conditions. Various experimental methods in the Laboratory were conducted using concrete specimens made from various materials in the exposed and submerged conditions. Researches in the field were carried out on existing structures with a certain building age using non-destructive testing. Meanwhile, the analytical methods applied simple equations and numerical simulation computational software.

Assessment of Timber Structures Using the X-Ray Technology

2013 ◽  
Vol 778 ◽  
pp. 321-327 ◽  
Author(s):  
Steffen Franke ◽  
Bettina Franke ◽  
Florian Scharmacher
Keyword(s):  
Assessment Method ◽  
Normal Function ◽  
Structural Timber ◽  
Timber Structures ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
X Ray ◽  
Existing Structures ◽  
Effective Assessment ◽  
Non Destructive

The assessment of timber structures is a permanent task to check the normal function of individual structural timber elements. Non-destructive testing methods are preferred but the value of the information is limited due to the performance of the applied assessment method. However, X-ray is a technology which allows a view into the structural member or the connections. The mobile X-ray technology has been used in laboratory tests and practical situations at existing structures and led to excellent results which allowed detailed analyses. The method and its possibilities for non-destructive testing of timber structures will be presented. The results reached show a high potential for an effective assessment of existing structures including connections and structural timber members.

scholarly journals Assessment of Timber Roof Structures before and after Earthquakes

Buildings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 528
Author(s):  
Nikola Perković ◽  
Mislav Stepinac ◽  
Vlatka Rajčić ◽  
Jure Barbalić
Keyword(s):  
Test Methods ◽  
Timber Structures ◽  
Destructive Testing ◽  
Policy Makers ◽  
Load Bearing ◽  
Existing Structures ◽  
Roof Structure ◽  
Before And After ◽  
Timber Roof Structures ◽  
Non Destructive

The global objective of sustainable development has been greatly directed toward the preservation of existing structures. Therefore, condition assessment and reconstruction of existing timber structures have been gaining importance in recent times. This is particularly evident on timber roofs whose elements are exposed to degradation, either because of rheological effects or due to the direct influence of moisture and biological factors. In case of accidental events, such as an earthquake, the question of the structure’s condition is essential for the condition of the entire building. In order to prove the load-bearing capacity and serviceability of existing structures, as well as to check the need for reconstruction, it is necessary to define crucial parameters that are influencing the condition of materials, elements, and systems. Although there are many non destructive testing methods, the frequency and scope of their use, as well as the decision-making approach, have not been defined. In the paper, non-destructive and semi-destructive methods frequently used for timber structures are explained. A systematic review of criteria to be used in the assessment of load-bearing timber structures in a seismic active area was the main objective of this paper as well as the illustration of non-destructive and semi-destructive test methods through a case study involving roof construction of a hundred-year-old building in Zagreb, Croatia. Pre- and post-earthquake inspection was made. The overall condition of the roof structure after two significant earthquakes can be assessed as satisfactory given that the observed system is a large-span and massive roof structure. The presented results and identification of typical damages after the earthquake are presented in order to facilitate policy makers and for the future implementation of development strategies in the renovation of the city.

scholarly journals Effect of Fly Ash as Cement Replacement on Chloride Diffusion, Chloride Binding Capacity, and Micro-Properties of Concrete in a Water Soaking Environment

2020 ◽  
Vol 10 (18) ◽  
pp. 6271 ◽  
Author(s):  
Jun Liu ◽  
Jiaying Liu ◽  
Zhenyu Huang ◽  
Jihua Zhu ◽  
Wei Liu ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Fly Ash ◽  
Binding Capacity ◽  
Chloride Ion ◽  
Chloride Content ◽  
Chloride Ions ◽  
Chloride Diffusion ◽  
Chloride Binding ◽  
Test Results ◽  
New Equation

This paper experimentally studies the effects of fly ash on the diffusion, bonding, and micro-properties of chloride penetration in concrete in a water soaking environment based on the natural diffusion law. Different fly ash replacement ratio of cement in normal concrete was investigated. The effect of fly ash on chloride transportation, diffusion, coefficient, free chloride content, and binding chloride content were quantified, and the concrete porosity and microstructure were also reported through mercury intrusion perimetry and scanning electron microscopy, respectively. It was concluded from the test results that fly ash particles and hydration products (filling and pozzolanic effects) led to the densification of microstructures in concrete. The addition of fly ash greatly reduced the deposition of chloride ions. The chloride ion diffusion coefficient considerably decreased with increasing fly ash replacement, and fly ash benefits the binding of chloride in concrete. Additionally, a new equation is proposed to predict chloride binding capacity based on the test results.

scholarly journals Effect of the Electric Field on the Distribution Law of Chloride Ions and Microstructure in Concrete with the Addition of Mineral Admixtures

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1380 ◽  
Author(s):  
Xiaoli Xie ◽  
Qingge Feng ◽  
Zheng Chen ◽  
Wei Lu
Keyword(s):  
Electric Field ◽  
Pore Structure ◽  
Chloride Ions ◽  
Mineral Admixtures ◽  
Chloride Diffusion ◽  
Electric Field Effect ◽  
Nacl Solution ◽  
Distribution Law ◽  
Chloride Migration ◽  
Chloride Profile

Migration testing of chloride under an electric field is a fast and effective method to determine the corrosion resistance of reinforced concrete against chloride. In this study, a series of admixture-involved (fly ash and slag) concrete specimens were produced for an accelerating chloride diffusion test in 3% NaCl solution under an electric field and natural chloride diffusion in 165 g/L NaCl solution under immersion conditions. Then, the chloride profile and pore structure of concretes aged 56 and 91 days were compared to investigate the effect of the electric field on chloride diffusion as well as the microstructure of the concrete. The results showed that, under accelerating electric field conditions, the degree to which chloride refined the internal pore structure of the concrete was weaker than that under natural immersion conditions. The applied electric field changed the pore structure inside the concrete, but it had little effect on the distribution of total, free, and bound chlorides and their mutual relationship. In addition, it is necessary to consider that the electric field effect on chloride migration varies with the concrete mix proportions.

scholarly journals Investigation on Durability Performance in Early Aged High-Performance Concrete Containing GGBFS and FA

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Seung-Yup Jang ◽  
Subbiah Karthick ◽  
Seung-Jun Kwon
Keyword(s):  
Diffusion Coefficient ◽  
High Performance ◽  
High Performance Concrete ◽  
Steel Corrosion ◽  
Chloride Ions ◽  
Chloride Diffusion ◽  
Structural Safety ◽  
Concrete Durability ◽  
Chloride Diffusion Coefficient ◽  
Rc Structures

The significance of concrete durability increases since RC (Reinforced Concrete) structures undergo degradation due to aggressive environmental conditions, which affects structural safety and serviceability. Steel corrosion is the major cause for the unexpected failure of RC structures. The main cause for the corrosion initiation is the ingress of chloride ions prevailing in the environment. Hence quantitative evaluation of chloride diffusion becomes very important to obtain a chloride diffusion coefficient and resistance to chloride ion intrusion. In the present investigation, 15 mix proportions with 3 water-to-binder ratios (0.37, 0.42, and 0.47) and 3 replacement ratios (0, 30, and 50%) were prepared for HPC (high-performance concrete) with fly-ash and ground granulated blast furnace slag. Chloride diffusion coefficient was measured under nonstationary condition. In order to evaluate the microstructure characteristics, porosity through MIP was also measured. The results of compressive strength, chloride diffusion, and porosity are compared with electrical charges. This paper deals with the results of the concrete samples exposed for only 2 months, but it is a part of the total test plan for 100 years. From the work, time-dependent diffusion coefficients in HPC and the key parameters for durability design are proposed.

Heavy Metals in Sediments from the Central New South Wales Coastal Region

1978 ◽  
Vol 29 (6) ◽  
pp. 777 ◽  
Author(s):  
A de Forest ◽  
SP Murphy ◽  
RW Pettis
Keyword(s):  
Heavy Metals ◽  
Environmental Assessment ◽  
Analytical Methods ◽  
New South ◽  
New South Wales ◽  
Coastal Region ◽  
South Wales ◽  
Coastal Marine ◽  
Sea Bed ◽  
Shelf Region

Coastal marine sediments were collected from 20 oceanographic stations along the central New South Wales coastal region in September 1975. Chemical and physical properties of the sediments were determined to establish analytical methods suitable for use in environmental assessment studies. Statistical analyses of the data indicated that this region is typical of an unpolluted continental shelf region, in which the sea bed is mainly composed of sand with some silt.

Integrity Management System for Fixed Offshore Structures Inspection Strategy

2004 ◽  
Author(s):  
Mohamed A. El-Reedy
Keyword(s):  
Management System ◽  
Offshore Structures ◽  
Assessment Method ◽  
Offshore Platforms ◽  
Offshore Structure ◽  
Structure Comparison ◽  
Actual Structure ◽  
Existing Structures ◽  
Integrity Management

The GUPCO offshore structure management system was developed as a part of an integrated infrastructure management system. This paper presents a case study of providing an integrity management system for inspection, evaluation and repair of the fixed offshore platforms in Gulf of Suez. The management system procedure is presented focusing on the first step for defining the highly risky weight to the lower risky weight structure based on API criteria for assessment of the existing structures. The risk analysis methodology for developing design and assessment criteria for fixed offshore structure based on consequence of failure is illustrated. In our case study the assessment method is applied for a number of fixed offshore structures. The above methodology is performed after theoretical assessment and then verifying by using ROV subsea inspection for the fixed offshore structure. Comparison between the actual structure performance and the predicting risk assessment for the structure from the model will be studied. The overall management system will be illustrated in scope of predictive maintenance philosophy and reliability for all offshore structures.

scholarly journals Effective and Apparent Diffusion Coefficients of Chloride Ions and Chloride Binding Kinetics Parameters in Mortars: Non-Stationary Diffusion–Reaction Model and the Inverse Problem

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5522
Author(s):  
Jerzy Jasielec ◽  
Jakub Stec ◽  
Krzysztof Szyszkiewicz-Warzecha ◽  
Artur Łagosz ◽  
Jan Deja ◽  
...  
Keyword(s):  
Diffusion Coefficients ◽  
Reaction Model ◽  
Chloride Ions ◽  
Diffusion Reaction ◽  
Chloride Diffusion ◽  
Accurate Estimation ◽  
Chloride Binding ◽  
Apparent Diffusion Coefficients ◽  
Binding Isotherms ◽  
Apparent Diffusion

A non-equilibrium diffusion–reaction model is proposed to describe chloride transport and binding in cementitious materials. A numerical solution for this non-linear transport with reaction problem is obtained using the finite element method. The effective chloride diffusion coefficients and parameters of the chloride binding are determined using the inverse method based on a diffusion–reaction model and experimentally measured chloride concentrations. The investigations are performed for two significantly different cements: ordinary Portland and blast furnace cements. The results are compared with the classical diffusion model and appropriate apparent diffusion coefficients. The role of chloride binding, with respect to the different binding isotherms applied, in the overall transport of chlorides is discussed, along with the applicability of the two models. The proposed work allows the determination of important parameters that influence the longevity of concrete structures. The developed methodology can be extended to include more ions, electrostatic interactions, and activity coefficients for even more accurate estimation of the longevity.

scholarly journals Reliability assessment of existing bridge constructions based on results of non-destructive testing

2018 ◽  
Vol 199 ◽  
pp. 06001 ◽  
Author(s):  
Stefan Küttenbaum ◽  
Alexander Taffe ◽  
Thomas Braml ◽  
Stefan Maack
Keyword(s):  
Measurement Data ◽  
Basic Research ◽  
Relevant Information ◽  
Structural Safety ◽  
Non Destructive Testing ◽  
Testing Methods ◽  
Destructive Testing ◽  
Uncertainty In Measurement ◽  
Existing Structures ◽  
Non Destructive

The non-destructive testing methods available for civil engineering (NDT-CE) enable the measurements of quantitative parameters, which realistically describe the characteristics of existing buildings. In the past, methods for quality evaluation and concepts for validation expanded into NDT-CE to improve the objectivity of measured data. Thereby, a metrological foundation was developed to collect statistically sound and structurally relevant information about the inner construction of structures without destructive interventions. More recently, the demand for recalculations of structural safety was identified. This paper summarizes a basic research study on structural analyses of bridges in combination with NDT. The aim is to use measurement data of nondestructive testing methods as stochastic quantities in static calculations. Therefore, a methodical interface between the guide to the expression of uncertainty in measurement and probabilistic approximation procedures (e.g. FORM) has been proven to be suitable. The motivation is to relate the scientific approach of the structural analysis with real information coming from existing structures and not with those found in the literature. A case study about the probabilistic bending proof of a reinforced concrete bridge with statistically verified data from ultrasonic measurements shows that the measuring results fulfil the requirements concerning precision, trueness, objectivity and reliability.

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