This project took place at a water sport complex near Quebec City, Village and t\vo large swimming pools. hue wanted to add an “Amazon River’ ri
Temporary High Initial Air Content Wet Process Shotcrete
The placement of high strength wet-mix shotcrete is sometimes complicated by the compromise required between obtaining suitable pumpability and shootability.
Architectural Challenges Are Nearly Routine for One Small Shotcrete Contractor
Twenty-five years ago I thought every1hing was going 10 be built out of shotcrete! However, after building severnl sandwich panel buildings. and facÂing the prospect of W(>()d floating acres and acres of venical walls. our little Seattle company retreated 10 011r growing spceialry of building zoo exhibits and aquariums around the Uniterl States. We enjoyed the artistic nature
Shotcrete for Underground Support
In November 1999 I had the opportunity to attend the Third International Symposium on Sprayed Concrete for Underground Support.
Slope Reinforcement using Shotcrete in Arizona
With more than 7,000 cubic yards (5,350 m3) of shotcrete to be used for slope reinforcement in the MesaÂPayson Highway expansion in Arizona, it may be the biggest shotcrete application in the country. The project consists of shotcreting thirteen freshly-cut mountainsides in the Kitty Joe Canyon of the Matazel Mountain Range on Highway 87 between the cities of Mesa and Payson. The total cost of the 17-mile (27 km) road expansion is $55 million. “The entire project will take more than seven months to complete,” said Mickey Garner, president of Shotcrete Specialties, the sub-contractor. “And we’d be done if it hadn’t been for a freak snow last spring,” she continued. The area had about 3 feet (1 m) of snow just as the company was starting the project.
Use of Dry-Mix Shotcrete to Repair a Lighthouse Structure
This paper presents a description of the repair work carried out in 1996 at the Haut-Fond Prince lighthouse structure located in the St. Lawrence River, 8 km (5 mi) from the coast of Tadoussac, Quebec, Canada. The damaged section of the structure in the tidal zone was repaired using dry-mix shotcrete. Due to the particular field conditions (freezing-and-thawing cycles, ice erosion and im-pact, submersion of the repair zones only minutes after the application of shotcrete, etc.), the mixture used contained high early strength cement, silica fume, steel fibers, a liquid air-entraining admixture, and a powdered set-accelerator admixture. Removal of deteriorated concrete, preparation of the surface, replacement of the reinforcement, specifications for the shotcrete produced, as well as the application procedures are described in this article. A certifica-tion session was held to verify the skills of the nozzlemen. Only those qualified were authorized to apply shotcrete on the structure.
This article describes the repair work carried out at the Haut-Fond Prince structure located in the St. Lawrence River at the confluence of the Saguenay and the St. Lawrence rivers, 8 km (5 mi) from the coast of Tadoussac, Quebec, Canada (Fig. 1).
New Mixture Design and Guide Specifications and Inspector’s Manual
Shotcrete has not traditionally been a material of choice for repair of bridge structures by many state highway departments. One reason for this is that bridge engineers have not been aware of advances in the quality and durability possible with high-performance shotcrete over the last 10 to 15 years. In 1995, an effort was made to help facilitate and encourage the use of shotcrete in bridge repair, especially where it is particularly advantageous: in overhead and vertical surfaces and in thin layers, or a combination of thin and highly reinforced thick layers. The effort was organized by the AASHTO-AGC-ARTBA Joint Committee.
Application and Testing of Shotcrete
In 1989, the Austrian Concrete Society pub-lished a Guideline on Shotcrete that subse-quently served as a reference work and a contractual basis for shotcrete works in tunnel con-struction in Austria and abroad. Other standards,such as DIN 18551, focused more strongly on shotcrete for concrete repair works. At the end of 1998, after several revisions, a new edition of the Austrian Guideline was published that also con-siders recent developments in the field of shot-crete technology. Dealing with a
whole range of issues, from base ma-
Overcoming Pumping Problems
There is probably nothing as frustrating to even the most tolerant wet-mix shotcrete placing contractor or crew as problems related to pumping. While the following comments are spe-cifically related to shotcrete placement, many of them are also applicable to normal concrete pumping applications. The rheology of shotcrete mixtures is affected by the pumping pro-cess, which typically involves repetitively compressing a shotcrete mixture and forcing the mixture to the point of final placement under pressure.
Shotcrete Guides and Specifications
Most architects, design engineers and design-build contractors are familiar with preparing and producing specifications for various types of concrete construction. There are projects where the use of shotcrete, rather than cast concrete, may be more technically and economically advantageous, but the designer is reluctant to specify shotcrete because of a lack of familiarity in preparing shotcrete specifications. This article provides owners and designers con-sidering the use of shotcrete with information on guidelines and specifications for shotcrete in a variety of different applications. This information should assist designers in preparing project-specific specifications.