Anisotropic Fracture of Sandstone with Biotreated Cracks

Biotreatment has the potential to be used in restoration and conservation of stone-cultural relics, but less research has been focused on the anisotropic strength of rock with biotreated cracks. In this study, a series of Brazilian splitting tests (BSTs) was conducted on the intact disc sandstone specimens to generate mimicking natural cracks. A specifically designed biocementing system was then adopted to form effective biocementation between the two halves of the specimen, as indicated by microimages. The sandstone specimens with a biotreated crack were then subjected to BSTs at different loading angles. The apparent tensile strength (ATS) of the biotreated specimen can reach and even exceed that of the intact specimen, with low anisotropy. Furthermore, four failure modes are identified based on optical photos. The aforementioned findings reveal that the biotreatment is a remarkable method for repairing cracks of stone-cultural relics.