Petrography study on altered flint aggregate by alkali-silica reaction

Journal Article · Mon Nov 15 04:00:00 EST 2004 · Materials Characterization

DOI:https://doi.org/10.1016/j.matchar.2004.08.004· OSTI ID:20748648

Bulteel, D ^[1]; Rafai, N ^[2]; Degrugilliers, P ^[1]; Garcia-Diaz, E ^[1]

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1. Departement Genie Civil de l'Ecole Nationale Superieure des Techniques Industrielles et des Mines de Douai, 941 rue Charles Bourseul, B.P. 838, F-59508, DOUAI Cedex (France)
2. Laboratoire d'Etude et de Recherches des Materiaux a Arles, F-13631 ARLES (France)

The aim of our study is to improve our understanding of an alkali-silica reaction (ASR) via petrography. We used a chemical concrete subsystem: flint aggregate, portlandite and KOH. The altered flint aggregate is followed by optical microscopy and scanning electron microscopy (SEM) before and after acid treatment at different intervals. After acid treatment, the observations showed an increase in aggregate porosity and revealed internal degradation of the aggregate. This degradation created amorphous zones. Before acid treatment, the analyses on polished sections by scanning electron microscopy coupled with energy dispersive spectroscopy (EDS) enabled visualization of K{sup +} and Ca{sup 2+} penetration into the aggregate. The appearance of amorphous zones and penetration of positive ions into the aggregate are correlated with the increase in the molar fraction of silanol sites. This degradation is specific to the alkali-silica reaction.

• OSTI ID: 20748648
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Journal Issue: 2-4 Vol. 53; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CALCIUM IONS
CATIONS
CONCRETES
OPTICAL MICROSCOPY
POROSITY
POTASSIUM HYDROXIDES
SCANNING ELECTRON MICROSCOPY
SILICA
SPECTROSCOPY
ZONES