The technical paper Modern, High-Performance Wet Shotcrete A Holistic Approach that appeared on pp. 18-19 in the December 2012 issue expressed a technical inaccuracy that occurred during editing. In fact, steel fibers do not provide protection against spalling in fires; that is achieved by appropriate micro-synthetic fibers.
The original paragraph that appeared under the Fibers subhead read: The use of fibers as a reinforcing element of your shotcrete, or for the purposes of resisting spalling in the event of an underground fire, is realistically the subject of an article in and of itself. Suffice to say that, over the last 15 years, the author has seen steel fibers become a more widespread and preferential alternative to wire mesh, as a reinforcing element, and that now Macro synthetic fibers are the evolutionary alternative of choice from a cost/performance benefit perspective over steel fiber.