Four thin spray-on liner (TSL) mixtures were produced and tested based on the performance requirements specified by EFNARC (2008). They generally showed good tensile and bond strengths; however, one powder-type TSL mixture was shown to be unsuitable as a permanent support member (a 'Class S' TSL), because its elongation at break was much lower than the EFNARC (2008) specification. Two-component TSLs consisting of a liquid polymer and a powder binding material were more ductile and generally performed better than the one-component powder mixtures. Their high ductility resulted in increased elongation at break, even though their tensile strengths were slightly lower than those of the one-component powder TSLs. One prototype two-component TSL produced here satisfied every criterion specified by EFNARC (2008). Notably, it increased the average compressive strength of mortar specimens by over 20% even when coated to a thickness of only 3 mm.

To protect underground structures and passengers from fire, it is essential to characterize fire-induced damage on the construction materials for underground structures. However, it is almost impossible and uneconomical to carry out full-scale fire tests in tunnels that are under public usage. In this study, a high temperature furnace capable of simulating RABT (Richtlinien für die Ausstattung und den Betrieb von Straßentunneln) fire curve was newly designed and manufactured. In the fire tests, furnace temperature is set to reach 1,200 within five minutes after ignition. The temperature of 1,200 was maintained for one hour, and the fire was extinguished after two hours had elapsed. From the temperature measurement by thermocouples embedded in test specimens, the depth of lost concrete was estimated to reach approximately 20 cm from the surface that was exposed to fire. In addition, the alteration of physico-mechanical properties and microstructures of concrete segments after fire tests were investigated from core specimens. The results show that the deterioration of material properties was up to 10 cm from the surface of the remaining concrete block

To investigate failure and damage mechanisms in rock, a moment tensor inversion procedure named the SiGMA (Simplified Green's function for Moment tensor Analysis) was applied to acoustic emission (AE) data measured during uniaxial compression and three-point bending tests. In addition, the relative crack volume estimated from the moment tensor analysis was used as the damage index. This paper reports the applicability of the moment tensor analysis to estimate failure planes in rock, as well as to investigate rock failure mechanisms.