A note on the strength and deformation properties of a some sandstone under three-point bending in the context of tension and compression behaviour

The results of the three-point bending test of the Brenna sandstone beam samples are presented. The values of strains at the peak strength of the tensile part was epsilon(xmax), the strength of three-point bending was sigma(b) and the modulus of longitudinal elasticity (of the tensile part) was E-b - all of these values were indicated. The values of constants obtained in the three-point bending tests were compared with those obtained in the uniaxial tensile and compressive tests and the Brazilian tests. For this typical sandstone, values of constants determined by the threepoint bending tests are greater than those determined by the direct tensile tests. There were stated large differences in the tensile strength values (sigma(b)/sigma(T)approximate to 3) and relatively small differences in the elasticity modulus E (E-b/E-T approximate to 1.2).