Experimental study of the mechanical performances of sandstone blocks healed with mortar taken from shotcrete basic mix

Abstract

Shotcrete has been widely used in geotechnical engineering to support jointed rock masses. In spite of providing normal forces to enhance the resistance capability of rock masses, shotcrete materials were also capable of healing joints through penetration. In present study, to better verify the healing efficiency of the shotcrete method, a series of experimental investigations have been undertaken to check the mechanical performances of sandstone blocks which are healed with shotcrete mater0ials. To account for small joint gap, the mortar taken from shotcrete basic mix was firstly prepared by eliminating coarse aggregates with particle diameter larger than 3.0 mm. Then, the mortar materials were incorporated to prepare integrated sandstone samples through healing the joint between two opposite rock blocks. Afterwards, uniaxial compression tests were carried out on these integrated sandstone samples. The influences of joint orientation and joint roughness on the failure and strength behaviors of integrated sandstone samples were investigated. Test results showed that the mechanical performances of sandstone blocks healed with mortar taken from shotcrete basic mix were significantly dependent of the joint geometry. The motivation of intact rock strength to resist compression loads would increase the healing efficiency of the shotcrete materials, while the failure of the shotcrete materials would reduce this efficiency.