The influence of alkali-free and alkaline shotcrete accelerators within cement systems
Influence of the temperature on the sulfate attack mechanisms and damage
METADATA ONLY
Loading...
Author / Creator
Date
2003-03
Publication Type
Journal Article
ETH Bibliography
yes
Citations
Altmetric
METADATA ONLY
Data
Rights / License
Abstract
The resistance to sulfate attack of mixtures accelerated with alkali-free and alkaline accelerators was found to be mainly influenced by the Al³⁺ and SO₄²⁻ added via the admixtures. Microstructural observations showed decalcification and disintegration of the CSH gel, which acted as an additional Ca²⁺ supplier as compared to the CH for ettringite formation. The CSH decalcification was mainly observed with a homogeneous distribution of the alkali-free admixture. The disintegration of the CSH gel increased the porosity and allowed more sulfate solution to penetrate into the specimens. This process promoted the swelling of the specimens and directly contributed to the expansion, explaining the lack of a direct relationship between the ettringite formation and the expansion. Moreover, the CSH gel disintegration, typical for MgSO₄ attack, also occurred with Na₂SO₄ solutions and depending on the aluminate-sulfate distribution and the extent of the CSH gel disintegration, different damage types were detected. At higher temperatures (65 °C) the damage was mainly controlled by the growth, the rearrangement and the thermal stability of ettringite. © 2002 Elsevier Science Ltd. All rights reserved.
Permanent link
Publication status
published
External links
Editor
Book title
Journal / series
Volume
33 (3)
Pages / Article No.
387 - 395
Publisher
Elsevier
Event
Edition / version
Methods
Geographic location
Date collected
Date created
Subject
Durability; Accelerators; CSH gel; Ettringite; Temperature
Organisational unit
Notes
Received 20 September 2000, Accepted 13 August 2002, Published online 13 September 2002.