Alkali-aggregate reaction under the influence of deicing salts in the Hokuriku district, Japan

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

DOI:https://doi.org/10.1016/j.matchar.2004.07.003· OSTI ID:20748647

Katayama, Tetsuya ^[1]; Tagami, Masahiko ^[1]; Sarai, Yoshinori ^[1]; Izumi, Satoshi ^[2]; Hira, Toshikatsu ^[2]

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1. Department of Concrete Maintenance, Kawasaki Geological Engineering Co. Ltd., 2-11-15 Mita, Minato-ku, Tokyo 108-8337 (Japan)
2. Kanazawa Technical Office, Hokuriku Branch, Japan Highway Public Corporation, 170 Kaminomachi-higashi, Kanazawa 920-0365 (Japan)

Concrete cores taken from highway bridges and culverts undergoing alkali-silica reaction (ASR) were investigated petrographically by means of core scanning, point counting, polarizing microscopy, scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), electron-probe microanalysis with energy-dispersive spectrometry, in conjunction with wet chemical analyses and expansion tests. Field damage was roughly proportional to the content of andesite in the gravel aggregates due to the presence of highly reactive cristobalite and tridymite. Electron-probe microanalyzer analysis of unhydrated cement phases in the concrete revealed that the cement used had contained at least 0.5% to 1.0% alkali (Na{sub 2}Oeq) and that both the aggregates and the deicing salts had supplied part of the water-soluble alkali to concrete toward the threshold of producing ASR (Na{sub 2}O{sub eq} 3.0 kg/m{sup 3}). An accelerated concrete core expansion test (1 M NaOH, 80 deg. C) of the damaged structures mostly gave core expansions of >0.10% at 21 days (or >0.05% at 14 days), nearly comparable to those of a slow expansion test with saturated NaCl solution (50 deg. C, 91 days) which produced Cl-containing ASR gel.

• OSTI ID: 20748647
• 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

36 MATERIALS SCIENCE
BRIDGES
CEMENTS
CONCRETES
CRISTOBALITE
DAMAGE
ELECTRON MICROPROBE ANALYSIS
ELECTRON PROBES
EXPANSION
GELS
JAPAN
MICROSCOPES
ROADS
SALTS
SCANNING ELECTRON MICROSCOPY
SILICA
SODIUM CHLORIDES
SODIUM HYDROXIDES
SOLUTIONS
X-RAY DIFFRACTION