Electrochemical repair Use of electrochemical migration to mitigate alkali-silica reaction in large scale concrete structures

2011 ◽  
pp. 137-146
Keyword(s):  
Large Scale ◽  
Concrete Structures ◽  
Alkali Silica Reaction ◽  
Electrochemical Migration

scholarly journals Damage Mechanism Evaluation of Large-Scale Concrete Structures Affected by Alkali-Silica Reaction Using Acoustic Emission

2018 ◽  
Vol 8 (11) ◽  
pp. 2148 ◽  
Author(s):  
Vafa Soltangharaei ◽  
Rafal Anay ◽  
Nolan Hayes ◽  
Lateef Assi ◽  
Yann Le Pape ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Nuclear Power ◽  
Power Plants ◽  
Large Scale ◽  
Concrete Structures ◽  
Volumetric Strain ◽  
Damage Mechanism ◽  
Recognition Algorithm ◽  
Alkali Silica Reaction ◽  
The Common

Alkali-silica reaction has caused damage to concrete structures, endangering structural serviceability and integrity. This is of concern in sensitive structures such as nuclear power plants. In this study, acoustic emission (AE) was employed as a structural health monitoring strategy in large-scale, reinforced concrete specimens affected by alkali-silica reaction with differing boundary conditions resembling the common conditions found in nuclear containments. An agglomerative hierarchical algorithm was utilized to classify the AE data based on energy-frequency based features. The AE signals were transferred into the frequency domain and the energies in several frequency bands were calculated and normalized to the total energy of signals. Principle component analysis was used to reduce feature redundancy. Then the selected principal components were considered as features in an input of the pattern recognition algorithm. The sensor located in the center of the confined specimen registered the largest portion of AE energy release, while in the unconfined specimen the energy is distributed more uniformly. This confirms the results of the volumetric strain, which shows that the expansion in the confined specimen is oriented along the thickness of the specimen.

Experimental study of deformation processes in large-scale concrete structures under quasistatic loading

2020 ◽  
Vol 15 (5) ◽  
pp. 619-633
Author(s):  
Igor Shardakov ◽  
Irina Glot ◽  
Aleksey Shestakov ◽  
Roman Tsvetkov ◽  
Valeriy Yepin ◽  
...  
Keyword(s):  
Experimental Study ◽  
Large Scale ◽  
Concrete Structures ◽  
Deformation Processes ◽  
Quasistatic Loading

scholarly journals Optimising an expansion test for the assessment of alkali-silica reaction in concrete structures

2011 ◽  
Vol 44 (9) ◽  
pp. 1641-1653 ◽  
Author(s):  
Xiao Xiao Gao ◽  
Stéphane Multon ◽  
Martin Cyr ◽  
Alain Sellier
Keyword(s):  
Concrete Structures ◽  
Alkali Silica Reaction ◽  
Expansion Test

scholarly journals A Simulation Study of Fast Neutron Imaging for Large-scale Concrete Structures

2014 ◽  
Vol 60 ◽  
pp. 324-326 ◽  
Author(s):  
Y. Seki ◽  
T. Hashiguchi ◽  
H. Ota ◽  
S. Wang ◽  
A. Taketani ◽  
...  
Keyword(s):  
Fast Neutron ◽  
Simulation Study ◽  
Large Scale ◽  
Concrete Structures ◽  
Neutron Imaging

scholarly journals Durability of pulverised fuel ash (PFA) concrete exposed to acidic and alkali conditions

2019 ◽  
Vol 258 ◽  
pp. 05015 ◽  
Author(s):  
Saiful Baharin Duraman ◽  
Md. Fadhil Hakim Haji Omar
Keyword(s):  
Concrete Structures ◽  
Pozzolanic Reaction ◽  
Polluted Water ◽  
Alkali Silica Reaction ◽  
Acid Attack ◽  
Fuel Ash ◽  
Alkaline Environments ◽  
High Alkalinity ◽  
Acidic Conditions ◽  
Strength And Durability

Pulverised Fuel Ash (PFA) is becoming an important component in concrete due to potentially improved properties such as workability, later age strength and durability. Concrete structures may be susceptible to acid attack due to exposure to acid rain, acidic soil or polluted water. Concrete structures exposed to high alkaline environments, in addition to the alkalinity level of the cement and aggregates, may promote alkali-silica reaction (ASR) leading to swelling and reduction in durability. This study looks into the durability properties of PFA incorporated concrete at various replacement levels when exposed to highly acidic and alkali conditions. Compressive strengths and water absorption tests were compared between concrete cured under normal conditions with concrete exposed to highly acidic and highly alkali conditions. All specimens exposed to acidic conditions showed significant decreases in mass and compressive strengths compared to specimens cured normally. Higher PFA replacement resulted in improved resistance to acid attack. All specimens exposed to alkali conditions showed minor increases in mass suggesting ASR occurring. Reductions in compressive strengths were found at lower replacement levels. At higher replacement levels, increases in compressive strengths were found, suggesting the possibility of increased pozzolanic reaction of the PFA due to the high alkalinity.

Crack width calculation methods for large-scale concrete structures for the Ferry-Free E39

2018 ◽  
Author(s):  
Reignard Tan ◽  
Terje Kanstad ◽  
Mette R. Geiker ◽  
Max A. N. Hendriks
Keyword(s):  
Cross Sections ◽  
Calculation Method ◽  
Crack Width ◽  
Large Scale ◽  
Concrete Structures ◽  
Calculation Methods ◽  
Empirical Formulas ◽  
Eurocode 2 ◽  
Semi Empirical

<p>Motivated by the establishment of a Ferry-Free E39 coastal highway route, crack width calculation methods for design of large-scale concrete structures are discussed. It is argued that the current semi-empirical formulas recommended by Eurocode 2 is inconsistent and overly conservative for cross sections with large bar diameters and covers. A suggestion to formulating a more consistent crack width calculation method is given.</p>

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