Laboratory investigation into curing temperature on the mechanical characteristics of cement mortar serving in rock bolting system.

The effect of the curing temperature of cement mortar on the mechanical and deformation characteristics of the full encapsulated rock bolting system was not considered in most previous studies. To reveal the temperature-dependent behavior of cement mortar and bolt-grout interface in terms of strength and deformation characteristics, extensive tests over a curing temperature range of 2–60 ℃ were carried out in this study, including uniaxial compression tests of cement mortar, direct shear tests of cement mortar under both constant normal load (CNL) and constant normal stiffness (CNS) boundary conditions, and direct shear tests of the bolt-mortar interface under CNL boundary conditions. The results showed that the uniaxial compression and shear strength of cement mortar increase with curing temperature at 2–40 ℃ and reduce slightly at 40–60 ℃. Moreover, the effect of CNS boundary conditions was discussed. Furthermore, the evolution of shear strength and dilation limit of bolt-mortar interface with curing temperature was revealed. Based on the experimental results, suggestions for supporting the design of rock bolting systems under high- or low-temperature geological environments are given. [ABSTRACT FROM AUTHOR]