Effect of an Early-Age Exposure on the Degradation Mechanisms of Cement Paste under External Sulfate Attack

Among the most significant causes of concrete degradation is ESA (external sulfate attack). The majority of studies are currently conducted on samples that have been saturated and matured. Concrete structures, however, are exposed to the environment once the formwork has been removed. The purpose of...

Full description

Saved in:
Bibliographic Details
Published inMaterials Vol. 16; no. 17; p. 6013
Main Authors Metalssi, Othman Omikrine, Ragoug, Rim, Barberon, Fabien, Lacaillerie, Jean-Baptiste d’Espinose de, Roussel, Nicolas, Divet, Loïc, Torrenti, Jean-Michel
Format Journal Article
LanguageEnglish
Published Basel MDPI AG 01.09.2023
MDPI
Subjects
Age
Aluminates
Cement
Cement paste
Chemical Sciences
Concrete
Concrete deterioration
Concrete structures
Curing
Degradation
Dissolution
early-age effect
Ettringite
external sulfate attack
Formwork
Gypsum
Humidity
Hydration
Material chemistry
Mechanical properties
NMR
Nuclear magnetic resonance
physicochemical behavior
Portland cements
Reagents
Sodium
sulfate ingress
Sulfates
France
Online AccessGet full text

Cover

More Information
Summary:Among the most significant causes of concrete degradation is ESA (external sulfate attack). The majority of studies are currently conducted on samples that have been saturated and matured. Concrete structures, however, are exposed to the environment once the formwork has been removed. The purpose of this study is to determine what effects early exposure to external sulfates may have on degradation mechanisms. Microstructure, physical, and chemical behavior are monitored using a variety of experimental techniques, including NMR (27Al and 29Si), ICP, XRD, MIP, and SEM. Based on expansion measurements, mature Portland cement paste, unlike the early-age case, degraded rapidly due to the presence of compressed ettringite and gypsum, highlighted by SEM analysis. During ESA, sulfate ions diffuse through the cement matrix and are bound by chemical agents. Chemical analyses indicate that the chemical mechanism varies with the duration of curing. At an early age, external sulfates and aluminates are the most important reagents. For matured cases, these reagents include external sulfates, calcium derived from CH dissolution, and aluminates derived from the total dissolution of AFm.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:1996-1944
1996-1944
DOI:10.3390/ma16176013