Determination of the elastic properties of lightweight aggregate by ultrasonic pulse velocity measurement

Abstract

Lightweight aggregate is the main influence which determines the properties of lightweight concrete. The measurement of the physical properties of these aggregates is impeded by the fact that the material exists only as grains and that the production of a larger specimen for tests such as the evaluation of stress-strain relationship will change its properties. To obtain defined physical properties of the aggregates for a structural approach to concrete strength, ultrasonic methods were used. Pulse velocities of longitudinal and transversal waves were measured, and the values ror modulus of elasticity, shear modulus and Poisson's ratio were calculated. A calibration of these values for wellknown materials such as steelsand glass shows an accuracy of better than one percent. Values for some expanded clays and pumice are given.