Geopolymer microstructure using polarization and fluorescence microscopy

Author(s): Siska L.A. Valcke, R.B. Polder, H.J.F. Beijersbergen van Henegouwen
Paper category: Conference
Book title: 2nd International conference on Microstructural-related Durability of Cementitious Composites
Editor(s): Guang Ye, K. Van Breugel, Wei Sun, Changwen Miao
Print ISBN: 978-2-35158-129-2
e-ISBN: 978-2-35158-123-0
Publisher: RILEM Publications SARL
Pages: 1231 - 1239
Total Pages: 8
Language: English

The microstructure of concrete determines its (gas, water and ion) transport properties and therefore microstructure is a crucial parameter in concrete durability. Because of the intrinsically dense microstructure of geopolymer aluminosilicate reaction products, concrete made with geopolymer has the potential to be very durable. So far geopolymer durability studies have shown contrasting results. These studies often were considering the microstructure through bulk porosity measurements and high resolution techniques such as electron microscopy, thereby missing relevant information, such as heterogeneities and spatial variations of the hardened paste, microcracks, air voids, aggregate paste interface etc.

This study evaluates polarization and fluorescence microscopy, a technique often used in cement concrete studies but not yet for geopolymer concrete, to assess the microstructure. For the particular fly ash geopolymer mortar in this study, it is shown that even though a good strength performance is obtained, the microstructure consists of a lot of air voids and microcracks in between the dense geopolymer paste. This type of microstructure allows the geopolymer mortar to absorb and transport water faster compared to Portland cement mortar, which may have implications for the durability of this particular geopolymer mortar.

Online publication: 2013
Publication Type: full_text
Public price (Euros): 0.00