Determination of plastic and brittle states of “pool” bitumens

Abstract This paper deals with the determination of the plastic and brittle states of bitumens by means of three mechanical tests, viz., tensile strength, ductility and impact. Brittleness is defined us failure due to the hydrostatic component of stress whereas plastic failure is duo to the shear component. This definition leads to suitable tests for brittleness of materials. The ductility teat is applicable to the determination of the strain which the material can conveniently accommodate, whereas the tensile strength test is directly applicable to the matter under consideration, since brittleness deepends on rate of loading and this factor is controlled in this form of test. Impact tests show that all the bitumens tested are brittle when rapidly loaded; the most satisfactory criterion here is the impact energy or what may be determined the brittle strength.