UndergroundInternationalShotcrete for Underground Support IX
Dudley R. Morgan
Read MoreThe Japan Tunnelling Association (JTA) and International Tunnelling Association (ITA) sponsored the Shotcrete for Underground Support IX Conference held in Kyoto, Japan, from November 17-20, 2002. It is a cooperative conference with the United Engineering Foundation, New York, which sponsored the previous eight conferences, the
RepairUndergroundStructuralSilica Fume in Shotcrete
John Wolsiefer, Sr., and Dudley R. Morgan
Read MoreSilica fume is a highly pozzolanic mineral admixture that has been used mainly to improve concrete durability and strength and as portland cement replacement. Silica fume has been used primarily in the United States, Canada, and the Scandinavian countries, but is now finding increasing use
UndergroundInternationalSissach’s Saved by a Bypass
Daniel Herzog
Read MoreThe small village of Sissach, near Basel, in Switzerland is one of the nicest Swiss villages in the country, but the serenity is plagued each rush hour by heavy commuter traffic. The solution was a bypass tunnel running through the Chienberg hill to the north
UndergroundStructuralSpecification of Shotcrete Toughness
Roland Heere and Dudley R. (Rusty) Morgan
Read MoreFiber-reinforced shotcrete has become an established material for ground support in tunnelling and mining applications as well as in new construction and infrastructure repair. Designers and speciï¬ers frequently require such shotcrete to maintain some quantiï¬able postcrack strength or toughness. Until the newly published round panel
UndergroundStructuralSteep Slope Stabilization with Fiber-Reinforced Shotcrete
Michael Ballou
Read MoreFor the past 150 years or so, roads have been built through the mountain passes in the western U.S. and Canada. Sometimes these roads led to mines; sometimes they started as logging roads. Some were built for access roads for the railroad. Many were built
UndergroundInnovative Shotcrete Application Over Geofoam Structure Supporting Boston’s Central Artery Tunnel
David Jamieson
Read MoreThe objective of Boston’s Central Artery/Tunnel (CA/T) Project is to ease the congestion of approximately 190,000 vehicles per day traveling through the city of Boston. This objective is being achieved through the total reconstruction of Interstate Highway I-93 as it passes through the heart of
UndergroundSteel Fibrous Shotcrete: A Summary of the State-of-the-Art
Charles H. Henager
Read MoreSteel fibrous shotcrete has been used for mine and tunnel linings, for rock slope stabilization, in dam construction, for repair deteriorated surfaces and arches, for fire protection coatings and in thin-shell dome construction.
UndergroundCombining Shotcrete Mixes for Maximum Performance
J. Denis P. O’Donnell, Sr.
Read MoreRebound is an essential element in the application of shotcrete. Rebound is deï¬ned as follows: œMainly large aggregate with some sand and cement that bounces or ricochets off the receiving surface and falls on to lower surfaces.1 There is a vital function that is achieved
UndergroundDetermination of Early-Age Ductility of Steel Fiber-Reinforced Shotcrete Lining System at INCO’s Stobie Mine
Jean-Francois Dufour, J. Denis P. O'Donnell, Sr., and Michael Ballou
Read MoreThe state of technology in shotcrete materials has evolved steadily throughout the world and particularly in North America during the last 20 years. The use of supplementary cementing materials such as silica fume, fly ash and slag, the new generations of chemical admixtures, and the
UndergroundIs Computerized Shotcreting a Possibility? It’s a Reality!
Michael Rispin
Read MoreA nozzleman who has made a transition from hand-nozzling to using a robotic arm knows the value that mechanical technology has brought to our industry. Far beyond just saving human backs and arms during a shift of spraying concrete, robotic arms (booms, lances, etc.) have