Laboratory studies of properties of the stone masonry in the Old Aswan Dam

Abstract

The paper describes the results of mechanical and physical tests carried out on the masonry of the Old Aswan Dam for later assessment of its seismic stability and structural integrity. Mechanical tests were performed on 150 mm diameter cores obtained from various stages of construction of the dam. Tests indicate that the masonry in the first heightening exhibits higher strength characteristics than the masonry in the rest of the dam. Noticeably lower strength properties of the masonry in the second heightening were due to a higher water/cement ratio. The weakest link in the masonry of all three stages of construction from the point of view of its mechanical performance was the granite-mortar interfacial region. Analyses of test results show that the modulus of elasticity and the splitting tensile strength of the masonry may be expressed as a function of the compressive strength using the power regression equation and the logarithmic regression equation, respectively. The split cylinder test provides a more reliable measure of the tensile strength of the stone masonry than the direct tension test. In general, a wide scatter of test results in relation to the mean value appeared to be an inherent characteristic of this type of masonry. Variations were more pronounced in the case of the Poisson’s ratio test and in all instances when fracture at the horizontal mortar-stone interface was a primary mode of failure.