Comparison of the condition of steel fiber-reinforced shotcrete with water-glass and alkali-free activators after more than 20 years of service in a subsea road tunnel. (18th April 2022)

• Record Type: Journal Article
• Authors: Javier Manquehual, Cristobal; Drevland Jakobsen, Pål; Gunnar Holter, Karl; De Weerdt, Klaartje; Danner, Tobias; Bruland, Amund
• Is Part Of: Construction & building materials. Volume 328(2022)
• Publication Date: 2022-04-18
• Subjects: XRD -- μ-XRF -- Sprayed concrete -- Sulfur -- Leaching -- Chloride; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2022.127090
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Shotcrete conditions investigated in the Nordkapp subsea road tunnel. Water-glass and alkali-free based accelerators. Lowest shotcrete density in all the cores lies in shotcrete joints. Ettringite enrichment in shotcrete joints where alkali-free accelerator was used. Serious leaching in the outermost 10 cm towards the traffic room. Abstract: The in-service condition of steel fiber-reinforced shotcrete installed more than 20 years ago as single-shell rock support lining in the Nordkapp subsea road tunnel was investigated. The novelty of this study is the comparison of shotcrete with water–glass and alkali-free activators in a saline groundwater environment. The lowest shotcrete density was obtained at joints between two adjacent shotcrete layers. In the case of alkali-free accelerator, ettringite enrichment was observed in these joints. Leaching appeared to be the main degradation mechanism in the outermost 10–15 cm towards the traffic room.