The static and dynamic modulus of concrete : in theory and in practise

Abstract

This work provides the basis for comparison between three methods for estimating the Young's Modulus of concrete on standard laboratory specimens and on full size beams measuring three and a half metres in length. The static method, the deflection method and the ultra-sonic pulse velocity method will be compared in detail. All three methods will be applied to test specimens of a low grade and a high grade of concrete, namely C15 and C40 respectively both at 28 days. The static method essentially involves the measurement of strain of standard cylinders subjected to a compressive stress. The aim of the deflection method is to establish a relationship between the static and the flexural modulus of a said concrete grade as a static test is impossible to perform on a full sized beam. The ultra-sonic pulse velocity method is the simplest and the quickest method. However, as will be discussed in this dissertation, the value of the elastic modulus obtained from the static method and the dynamic modulus resulting from the ultra-sonic pulse velocity method will be discussed along with a relation between the dynamic modulus and the flexural modulus and that between the compressive strength and the modulus of elasticity.