ABSTRACT
Abstract Plastic shrinkage cracking in bonded dry-mix shoterete subjected to a severe drying environment is investigated. A novel test method is used. Shotcrete is shot straight on a fully matured, rough sub-base which provides the dimensional restraint. The assembly is then transferred to a drying chamber where early age cracking is allowed to occur in the shotcrete overlay and crack characteristics are measured. It is found that the method is very effective in estimating the potential and extent of shrinkage cracking in shotcrete, and also in assessing the effectiveness of various types of fibers and additives. Both steel and polymeric macro-fibers are investigated which are seen not only to delay the formation of cracks but also reduce crack widths and total crack areas.
