Title: Improving the Durability of Accelerated Cured Precast Concrete with Simultaneous Curing and Protective Coating

Author(s): M. Brugger

Publication: Symposium Paper

Volume: 212

Issue:

Appears on pages(s): 113-126

Keywords: accelerated curing; compressive strength; concrete durability; epoxy resin; heat of hydration; microcracking; permeability; precast concrete; protective coating; silica fume; specification; sulfate resistance

DOI: 10.14359/12681

Date: 6/1/2003

Abstract:
During the production of the precast concrete tunnel lining segments (at low at- mospheric pressure steam curing) for the Adler Tunnel, a new system with simultaneous curing and protective coating was successfully applied for the first time (1996 and 1997). The segments are exposed to aggressive groundwater and high loads. As a follow-up of the Adler Tunnel the same system was used for tunnel sections of the Singapore Metro (1998 and 1999) and Metro Caracas (2002). The straight forward method with only a few production steps, consist of high- performance concrete with silica fume and a protective coating for excellent curing and for additional protection against aggressive environment. The coating consist of an aqueous epoxy resin dispersion, applied immediately after stripping on the whole hot concrete surface of 40 to 50 oC in a single operation with a layer thickness of 0.1 to 0.2mm. The results of microscopic analysis, water permeability and compressive strength, on covercrete of those segments, are considerably better than on uncoated segment concrete, which were cured by covering the segments with insulation matting after stripping.