Study of the relationship between fracture energy and concrete hydration degree through a finite element model

Resumo

The fracture energy of concrete is an important physical parameter that describes its behavior under
stress, and it is especially important for modeling concrete structures. As a consequence of the concrete stiffening
process, the fracture energy will depend, among other factors, on the degree of hydration of the material. The
development of a model that describes this process is important so that concrete behaviors can be predicted at
different ages. A form of modeling widely used is the Finite Element Method (FEM), which consists of a numerical
model to approximately determinate several physical behaviors. The inverse analysis through FEM starts from the
knowledge of some given parameters, from the constitutive laws of a material and from physical results, to
correlate a numerical model with similar result, in such a way that it is possible to determine the unknown
parameters. The objective of this work is to obtain the relationship between the degree of hydration and the fracture
energy of a concrete using the inverse analysis through its numerical modeling. Starting from the results of concrete
bending tests, its modulus of elasticity and compression strength, fracture energy was obtained with reverse
analysis through the FEM, using the DIANA software. The analysis was repeated for different degrees of
hydration, thus establishing a correction between hydration of the concrete and fracture energy.