scholarly journals Evaluation of Concrete Durability Performance with Sodium Silicate Impregnants

2014 ◽  
Vol 2014 ◽  
pp. 1-11
Author(s):  
Sang-Soon Park ◽  
Yun Yong Kim ◽  
Byung Jae Lee ◽  
Seung-Jun Kwon
Keyword(s):  
Electrical Potential ◽  
Steel Corrosion ◽  
Chloride Diffusion ◽  
Concrete Durability ◽  
Chloride Diffusion Coefficient ◽  
Different Types ◽  
Chloride Attack ◽  
Scale Test ◽  
Durability Performance

This paper presents an enhanced performance in concrete impregnated with silicate compound. Two different types of impregnant materials (inorganic and combined type) are applied to concrete samples with different strength grade (21 MPa and 34 MPa). Through lab-scale test, improved performances in impregnated concrete are evaluated regarding porosity, strength, chloride diffusion coefficient, permeability of air/water, and absorption. Long-term exposure tests including strength, chloride penetration depth and contents, and electrical potential for steel corrosion are performed for different marine conditions. While the surface-impregnated concrete shows marginal increase in strength, significant improvements of porosity, absorption, and permeability are evaluated. The resistance to chloride attack reasonably improved through simply spraying the inorganic silicate in atmospheric-salt spraying condition.

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.

Microstructure Analysis on LILW Waste Disposal Facility by Accelerated Steel Corrosion Tests

2013 ◽  
Vol 378 ◽  
pp. 194-197
Author(s):  
Ki Beom Kim ◽  
Jang Hwa Lee ◽  
Do Gyeum Kim
Keyword(s):  
Diffusion Coefficient ◽  
Waste Disposal ◽  
Concrete Structures ◽  
Steel Corrosion ◽  
Microstructure Analysis ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Reinforcing Bar ◽  
Disposal Facility ◽  
Chloride Attack

Concrete structures such as LILW waste disposal facility located near the sea may suffer from chloride attack damages. This study aims to analysis mock-up test for acceleration corrosion of reinforcing bar and its deterioration in concrete structures by XRD and chloride diffusion coefficient. Corrosion acceleration experiment test has been developed and used to evaluate the effect of corrosion of reinforcing bar caused by seawater on engineered barrier of LILW waste disposal facility.

scholarly journals Chloride Induced Reinforcement Corrosion in Mortars Containing Coal Bottom Ash and Coal Fly Ash

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1933 ◽  
Author(s):  
Esperanza Menéndez ◽  
Cristina Argiz ◽  
Miguel Ángel Sanjuán
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Bottom Ash ◽  
Steel Corrosion ◽  
Chloride Diffusion ◽  
Chloride Ingress ◽  
Chloride Diffusion Coefficient ◽  
Coal Bottom Ash ◽  
Coal Ashes

Coal bottom ash is normally used as aggregate in mortars and concretes. When it is ground, its characteristics are modified. Therefore, the assessment of its long-term durability must be realized in depth. In this sense, an accelerated chloride ingress test has been performed on reinforced mortars made of Portland cement with different amounts of coal bottom ash (CBA) and/or coal fly ash (CFA). Corrosion potential and corrosion rate were continuously monitored. Cement replacement with bottom and fly ash had beneficial long-term effects regarding chloride penetration resistance. Concerning corrosion performance, by far the most dominant influencing parameter was the ash content. Chloride diffusion coefficient in natural test conditions decreased from 23 × 10−12 m2/s in cements without coal ashes to 4.5 × 10−12 m2/s in cements with 35% by weight of coal ashes. Moreover, the time to steel corrosion initiation went from 102 h to about 500 h, respectively. Therefore, this work presents experimental evidence that confirms the positive effect of both types of coal ashes (CBA and CFA) with regard to the concrete steel corrosion.

scholarly journals Influence of Hydrostatic Pressure and Cationic Type on the Diffusion Behavior of Chloride in Concrete

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2851
Author(s):  
Huanqiang Liu ◽  
Linhua Jiang
Keyword(s):  
Diffusion Coefficient ◽  
Hydrostatic Pressure ◽  
Diffusion Model ◽  
Coupling Effect ◽  
Experimental Results ◽  
Chloride Diffusion ◽  
Concrete Durability ◽  
Chloride Diffusion Coefficient ◽  
Diffusion Behavior ◽  
Diffusion Source

The durability of the concrete in underground and marine engineering is affected by the underground and ocean environment. Chloride diffusion coefficient under hydrostatic pressure is a key parameter of concrete durability design under corresponding conditions. Therefore, this paper studies the diffusion behavior of chloride in different diffusion source solutions by experiment and simulation. Based on the experimental results, this paper proposes a new chloride diffusion model under the coupling effect of diffusion and convection. The interaction of ions and compounds in the diffusion source solutions, concrete pore fluid, and concrete material are considered in the new chloride diffusion model. The experimental results show that chloride diffusion rate is significantly affected by hydrostatic pressure, which increases with the increase of hydrostatic pressure. The chloride diffusion coefficient shows a certain difference in difference diffusion source solutions. The chloride diffusion coefficient in divalent cationic diffusion source solutions is the largest, the chloride diffusion coefficient in the divalent and monovalent cationic compound ones is in the middle, and the chloride diffusion coefficient in the monovalent cationic ones is the smallest. There is a linear relationship between the chloride diffusion coefficient and the hydrostatic pressure whether in single or combined cationic diffusion source solutions.

Effect of Stone Powder Content on the Diffusing Parameter and Diffusion Attenuation Coefficient of Chloride Ion of Mechanical Sand Concrete

2014 ◽  
Vol 584-586 ◽  
pp. 1818-1822
Author(s):  
Ming Qiang Qin ◽  
Wen Zhan ◽  
Wen Bing Xu ◽  
Jin Hui Li
Keyword(s):  
Attenuation Coefficient ◽  
Chloride Ion ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
River Sand ◽  
Moderate Amount ◽  
Powder Content ◽  
And Diffusion ◽  
Better Than

The effect of stone powder content on the chloride diffusion coefficient and diffusion attenuation coefficient of chloride ion of mechanical sand (MS) concrete was studied. The results showed that the resistance to chloride ion permeability of MS concrete firstly increased and then decreased with the increase of the content of stone powder. The anti-permeability of the concrete which had moderate amount of stone powder was better than that of the natural river sand (NS) concrete. The diffusion attenuation coefficient of MS concrete was greater than that of the NS concrete, which was good for long-term durability of concrete structure.

scholarly journals Durability and Aesthetics of Architectural Concrete under Chloride Attack or Carbonation

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 839 ◽  
Author(s):  
Chang ◽  
Wang ◽  
Jin ◽  
Li ◽  
Feng ◽  
...  
Keyword(s):  
Chloride Content ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Tidal Zone ◽  
Aesthetic Appearance ◽  
Free Chloride ◽  
Carbonation Resistance ◽  
Chloride Resistance ◽  
Chloride Attack ◽  
The Aesthetic

Architectural concrete has been wildly used nowadays, and those served in an offshore environment often suffer from chloride penetration and carbonation. To assess the protection and decoration performances of architectural concrete, this study exposed architectural concrete to actual marine environments and accelerated carbonation conditions. The chloride and carbonation resistance of architectural concrete was determined to evaluate the protection performance, and the corresponding surface-color-consistency was adopted to characterize its decoration performance. The results show that the total and free chloride of concrete in the marine atmosphere zone and the tidal zone generally decreases with depth; chloride content arguments significantly with exposure time, with a chloride maximum peak near the surface. Moreover, the chloride diffusion coefficient is small throughout the measurements, indicating the superior chloride resistance of architectural concrete. Furthermore, architectural concrete also possesses excellent carbonation resistance based on the carbonation depth data obtained from the carbonation experiment. Therefore, architecture concrete served as protection covers can withstand both the chloride attack and carbonation tested in this paper. In addition, carbonation was found to have a profound influence on the aesthetics of architectural concrete. Therefore, carbonation should be carefully handled for better maintaining the aesthetic appearance of architectural concrete in long-term service.

Durability Design of Tunnel Concrete Lining under Chloride Attack

2012 ◽  
Vol 594-597 ◽  
pp. 1014-1017
Author(s):  
Lu Feng Yang ◽  
Hong Bin ◽  
Yu Bo
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Chloride Ions ◽  
Chloride Diffusion ◽  
Concrete Lining ◽  
Chloride Diffusion Coefficient ◽  
Initial Value ◽  
Durability Design ◽  
Chloride Attack ◽  
Finite Element Formulations

Chloride induced corrosion of reinforcing steel is one of major causes of deterioration of tunnel concrete lining under chloride attack. In this paper, a finite element model for chloride ions transport in tunnel concrete lining was proposed based on the Fick’s second law of diffusion. The governing partial differential equation was solved numerically in space as a boundary-value problem and in time as an initial-value problem by means of the finite element formulations. The maximum allowable value of chloride diffusion coefficient of tunnel concrete lining with service life of 100a was achieved and some constructive suggestions for durability design of tunnel concrete lining under chloride attack were also proposed.

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