Fascia walls are structural earth retaining components for soldier pile and soil nail walls, and they are traditionally constructed with cast-in-place (CIP) concrete. In recent years, some state departments of transportation have begun to replace the CIP concrete with shotcrete for wall fascias. The primary difference between shotcrete and CIP concrete is that shotcrete is placed and consolidated pneumatically (using high-pressure air). This method of construction is attractive because of its potential for saving cost and construction time. However, it also has potential drawbacks that raise concerns about its durability. Currently very limited information is available to evaluate curing practices, construction, and long-term durability for shotcrete. Phase I of this research (see WA-RD 870.1) showed that the performance of shotcrete is viable and promising in comparison to CIP concrete and that, if fully investigated, shotcrete may replace CIP concrete and be suitable for other applications. This Phase 2 project will follow up on issues identified in Phase I, such as the influence of mix design criteria on early age and long-term performance and the effects of air content on long-term performance. With the increasing desire for highway agencies to use shotcrete for accelerated construction and rapid renewal, the results will be a useful resource to help WSDOT achieve the best structure quality and durability.
Principal Investigator: Pizhon Qiao, Civil and Environmental Engineering, WSU
Sponsor: WSDOT
WSDOT Technical Monitor: Brian Aldrich
WSDOT Project Manager: Mustafa Mohamedali
Scheduled completion: June 2019