Elastic Modulus Measurement Through Ambient Response Method

Abstract

Concrete endures strong evolution in its mechanical behaviour since casting, passing from a solid suspension to a structural material. It is extremely important to understand and be able to predict the structural behaviour of concrete since the beginning of the hardening process for a good structural design, particularly in regard to the development of self-induced stresses (due to heat of hydration and shrinkage). In order to collect data for the relevant phenomena that have been mentioned, it is important to have methods that allow continuous monitoring of the evolution of mechanical properties of concrete since very early ages, both in laboratory environment and ‘in-situ’. In such concern, an experimental method called EMM-ARM (Elasticity Modulus Measurement through Ambient Response Method) was proposed in 2009, which is based on the modal identification of a composite beam during the curing period of concrete, allowing the continuous measurement of the E-modulus of the tested material (e.g. concrete, mortar, cement paste) since casting. This chapter provides an overview of EMM-ARM principles, evolution through the last decade, as well as several examples of application and validation.