Impact of Microstructure on the durability of concrete
Author(s): K. Scrivener
Paper category: conference
Book title: Microstructural-related Durability of Cementitious Composites
Editor(s): Guang Ye, K. van Breugel, Wei Sun and Changwen Miao
Print ISBN: 978-2-35158-129-2
Publisher: RILEM Publications SARL
Publication year: 2012
Pages: 13 - 19
Total Pages: 7
Abstract: The blending of clinker with supplementary cementitious materials (SCMs) is the most promising route to increase the sustainability of cementitious materials.
In this paper I discuss the changes in microstructure brought about by addition of SCMs and the ways in which these impact durability. SCMs may have both positive and negative effects on durability depending on the exposure condition.
Resistance to carbonation will inevitably be reduced as blended cements contain lower amounts of lime which can react with CO2. This lowering of the buffering capacity may be partially offset by a less permeable microstructure if the materials are well cured. On the other hand chloride ingress is most likely to be reduced, due to lower permeability and improved binding capacity if the SCM contains alumina, which can form Friedel’s salt.
Risks of alkalis silica reaction are reduced by aluminosilicate SCMs, first due to the lowering of the pore solution pH, due to the lower C/S ratio C-S-H and secondly due to the inhibition of the dissolution of amorphous silica by alumina.
Sulfate attack is complex and it is difficult to predict the field performance of blended materials from standard laboratory tests.
Online publication: 2012-07-05
Publication Type: full_text
Public price (Euros): 0.00