The damage of rock joints or fractures upon shear includes the surface damage occurring at the contact asperities and the damage beneath the shear surface within the host rock. The latter is commonly known as off-fault damage and has been much less investigated than the surface damage. The main contribution of this study is to compare the results of direct shear tests conducted on saw-cut planar joints and tension-induced rough granite joints under normal stresses ranging from 1 MPa to 50 MPa. The shearinduced off-fault damages are quantified and compared with the optical microscope observation. Our results clearly show that the planar joints slip stably under all the normal stresses except under 50 MPa, where some local fractures and regular stick-slip occur towards the end of the test. Both post-peak stress drop and stick-slip occur for all the rough joints. The residual shear strength envelopes for the rough joints and the peak shear strength envelope for the planar joints almost overlap. The root mean square (RMS) of asperity height for the rough joints decreases while it increases for the planar joint after shear, and a larger normal stress usually leads to a more significant decrease or increase in RMS. Besides, the extent of off-fault damage (or damage zone) increases with normal stress for both planar and rough joints, and it is restricted to a very thin layer with limited micro-cracks beneath the planar joint surface. In comparison, the thickness of the damage zone for the rough joints is about an order of magnitude larger than that of the planar joints, and the coalesced micro-cracks are generally inclined to the shear direction with acute angles. The findings obtained in this study contribute to a better understanding on the frictional behavior and damage characteristics of rock joints or fractures with different roughness. (c) 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

Contemporary reinforced concrete structures suffer from the drawback of developing micro-cracks during their service due to causes related to shrinkage and fatigue. This may compromise their technical and functional serviceability due to the possible reduction in durability which may lead to a decrease in load carrying capacity of the structure. In recent years, experimental studies on biomineralization or biocementation have shown a potential to address this issue. Biocementation is the process in which microorganisms induce the production of calcium carbonate which can improve self-healing capabilities by filling the micro-cracks and pores in the structures, similar to the traditional lime-based materials. The most used pathway of biocementation is urea hydrolysis, which is brought about by the urease enzyme secreted by ureolytic bacteria. Although there have been numerous laboratory-scale studies that have yielded positive results, the widespread adoption of this technology in practical applications is still hindered by a range of constraints. The information about the solutions to resolve these limitations is fragmented and dispersed throughout the literature. This review aims to compile state-of-the-art knowledge in one place. This article provides a detailed assessment of the challenges in the application of biocementation and suggests strategies to overcome the obstacles that hinder its use in construction projects.