Shotcrete is a construction material used for reinforcement of the roof and walls of underground spans. Receipt, application, and then time-dependently monitoring the performance of shotcrete after spraying on is important to see the quality of the process and need to be studied substantially. The performance of shotcrete may be carried out by a number of tests and examinations in situ and laboratory. One of the most important laboratory tests is the "determination of energy absorption capacity of fiber reinforced slab specimens" (EN 14488–5) to find out the bearing capacity of shotcrete panels in a specific dimension (60 cm × 60 cm × 10 cm). Although the quality of aggregate, cement, and water is so effective for a desirable shotcrete mixture, the bearing capacity of it is enhanced by the existence of steel or polypropylene fibers. In this study, various fiber reinforced shotcrete slabs (FRSS) in which the amount and types of fibers are changed, were tested in the laboratories in order to find out the capability for a possible use in the spans of an underground mine. By the help of EN 14488–5, the energy absorption levels of FRSS are found out and discussed. The important results that may be derived from the tests are that considerable amount of fluctuations in the load-deflection performance and energy absorption levels of slabs may be seen when the amount and type of fibers were varied. These results are also discussed with respect to the material characteristic point of view.
Shotcrete (sprayed concrete or gunite) is a material sprayed on underground spans in order to cover rock surfaces circumferentially. It helps both stabilizing and acting rock fragments, blocks on roof and walls together. According to rock class of the media on which shotcrete sprayed, the shotcrete consistency may be changed. Plain shotcrete consists of water, cement and aggregate in a special dimension and volume. In order to increase pumping and cure ability, for instance, some additives like plasticizers may be added into the mixture. In order to gain strength fast, some accelerators are also included. Besides, some fibers, polypropylene, carbon, steel etc., help to increase the pre and post failure performance of shotcrete mixture.