Alkali-silica reaction products: Comparison between samples from concrete structures and laboratory test specimens

2010 ◽  
Vol 61 (12) ◽  
pp. 1379-1393 ◽  
Author(s):  
Šárka Šachlová ◽  
Richard Přikryl ◽  
Zdeněk Pertold
Keyword(s):  
Laboratory Test ◽  
Concrete Structures ◽  
Alkali Silica Reaction ◽  
Reaction Products

scholarly journals The role of SEM in the diagnosis of expansive chemical reactions in cement-based building materials

2008 ◽  
Vol 14 (S3) ◽  
pp. 95-96
Author(s):  
A. Santos Silva ◽  
M. Manuela Salta ◽  
P. Menezes ◽  
S. Couto ◽  
P. Adriano
Keyword(s):  
Building Materials ◽  
Correct Diagnosis ◽  
Concrete Structures ◽  
Alkali Silica Reaction ◽  
Reaction Products ◽  
Physico Chemical ◽  
Common Causes ◽  
Chemical Techniques ◽  
Loss Of Strength

The alkali-silica reaction (ASR) and internal sulfatic reaction (ISR), normally both referred as internal expansive reactions, are among the most common causes of concrete structures deterioration worldwide. These reactions, which could be present simultaneously, origin products those are responsible for expansive stresses in the cement-based building materials, leading to severe cracking and loss of strength. The reaction products are also often amorphous or badly crystallized, or even present in very low content that they are very difficult to identify by current analytical physico-chemical techniques. The main macroscopic evidence of these degradation phenomena in concrete structures are the superficial occurrence of map-cracking, pop-outs and exudates (figure 1). Nevertheless, these symptoms are not exclusive and enough to establish a correct diagnosis.

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 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.

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