Influence of Fiber Type on Creep Deformation of Cracked Fiber-Reinforced Shotcrete Panels

Abstract

This article describes how experience in underground construction to date has indicated that creep deformations in conventionally reinforced shotcrete and steel fiber-reinforced shotcrete (SFRS) are small once hardening beyond the initial few weeks of hydration has occurred. At the same time, shotcrete reinforced with macrosynthetic fibers has become well established as a means of ground support in mines. This type of fiber-reinforced shotcrete (FRS) has demonstrated an ability to deform in response to highly plastic ground and thereby control stability. However, debate has arisen about the merits of using shotcrete reinforced with macrosynthetic fibers in civil tunnel linings. In particular, concerns have been expressed about the magnitude of post-crack creep-related deflections likely in the long term. The present investigation was instigated to determine the relative magnitude of time-dependent post-crack deflections typical of shotcrete reinforced with macrosynthetic fibers and to compare this with SFRS tested under nominally identical conditions.