Microstructure of high-volume fly ash concrete

Title: Microstructure of high-volume fly ash concrete
Author(s): G. Baert, P. Van den Heede, K. Audenaert, N. De Belie
Paper category : conference
Book title: International Conference on Microstructure Related Durability of Cementitious Composites
Editor(s): W. Sun, K. van Breugel, C. Miao, G. Ye and H. Chen
Print-ISBN: 978-2-35158-065-3
e-ISBN: 978-2-35158-084-4
Publisher: RILEM Publications
Publication year: 2008
Pages: 207 - 215
Total Pages: 9
Nb references: 9
Language: English

Abstract: The resistance of concrete against multiple types of deterioration is governed by gas and/or fluid transport properties of the microstructure and hence by the permeability of the capillary network. The pozzolanic reaction of fly ash starts at later age and proceeds at a slower pace than the hydration of cement. This makes high-volume fly ash concrete at young age much more permeable and vulnerable to the transport of gasses and fluids than traditional concrete.
With time, a densification of the microstructure will take place resulting in an increased resistance of high volume fly ash concrete against penetration of aggressive gasses and fluids.
Eight concrete mixtures were made with varying fly ash-to-cementitious material ratio and with different types of cement and fly ash. At the ages of 1 and 3 months the compressive strength, the open porosity and the sorptivity of the concrete mixes was determined. The two latter parameters were measured after drying at 40°C (R.H. of 23%) and 105°C respectively.
The measured porosities were related to the compressive strength and to the sorptivity behaviour. The C3A content and the fineness of fly ash were found to be determining parameters for the microstructural development of concrete with these binders.

Online publication: 2009-06-09
Publication type : full_text
Public price (Euros): 0.00