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 DOTs have begun to replace the CIP concrete with shotcrete for wall fascias. This method of construction is attractive because of its potential for saving cost and construction time. However, it also has numerous potential drawbacks that raise durability concerns. Currently, the state of knowledge regarding the proper shotcrete mix design, construction, curing practices, quality assurance, durability performance, condition assessment, maintenance, and repair/rehabilitation is scattered in published domain or undocumented. In addition, most of the evaluation and test methods commonly developed for concrete cannot be directly applied or are not suitable for characterization of shotcrete. Therefore, the goal of this project is to provide a thorough review of the state of knowledge about shotcrete to ensure its proper use for wall fascia and slope stabilization. In particular, this project will investigate the adequacy of shotcrete consolidation, permeability, early age shrinkage and associated cracking, potential for early rebar corrosion and long-term durability. With the increasing desire for highway agencies to use shotcrete for accelerated construction and rapid renewal, such a synthesis will be a useful resource to help them achieve the best structure quality and durability.
Principal Investigator: Pizhong Qiao, Civil and Environmental Engineering, WSU
Sponsor: WSDOT
WSDOT Project Manager: Lu Saechao
Scheduled completion: June 2017