Guide to Shotcrete

Description

Shotcrete has grown into an important and widely usedconstruction technique. Because of continuing research anddevelopment in materials, equipment, and constructionprocedures, this guide is revised periodically to reflectcurrent industry practice. The guide was originally preparedto replace “Recommended Practice for Shotcreting” (ACI506-66, Revised 1983).

This guide, based on many years of practice and experi-ence, covers aspects of shotcrete construction includingmaterials, equipment, crew organization, preliminary prepa-ration, proportioning, shotcrete placement, and qualitycontrol. New construction, repair, linings, coatings, refracto-ries, underground support, and other special applications arealso discussed. An appendix on suggested methods ofpayment is included. Procedures vary from one region toanother, and adjustments may be required to meet the needsof a particular project. No attempt is made to provide guide-lines for the design of shotcrete installations.

In 1910, a double-chambered cement gun, based on adesign developed by Carl Akeley, was introduced to theconstruction industry. The sand-cement product produced bythis device was given the proprietary name Gunite. In theensuing years, trademarks such as Guncrete, Pneucrete,Blastcrete, Blocrete, Jetcrete, and the terms “pneumaticallyapplied mortar or concrete” and “sprayed concrete” wereintroduced to describe similar processes. The early 1930ssaw the generic term “shotcrete” introduced by the AmericanRailway Engineering Association to describe the Guniteprocess. In 1951, the American Concrete Institute adoptedthe term “shotcrete” to describe the dry-mix process. It isnow also applied to the wet-mix process and has gainedwidespread acceptance in the United States and around theworld (ACI Committee 506 1966).