The mean modulus of deformation (Ecd) is used as a measure of the modulus of elasticity of lightweight aggregate. It is not practical to measure the modulus of elasticity directly and so the mean modulus of deformation, which is the mean of ultrasonic measurements of the modulus of elasticity of individual aggregate particles, is used.
The FIP Manual of Lightweight Aggregate Concrete, References 25, suggests that the mean modulus of deformation can be directly related to the critical strength of ligthweight concrete, which in turn can be related to the ratio of the strength of concrete made with a particular lightweight coarse aggregate to the strength of concrete made with normal weight aggregate. Firstmix allows the user to specify the strength characteristics of the lightweight coarse aggregate by means of its mean modulus of deformation in the Laboratory Measurements Dialog.
Range: 2000 - 20000 MPa or 290000 - 2900000 psi.