Fracture Surfaces of Porous Materials

Fracture of Porous Materials Induced by Crystallization of Salt

The penetration of salt into porous materials is known to have deleterious effects, often resulting in fracture. The damage process begins with a saline solution penetrating the porous network by way of capillary action. This is followed by supersaturation of the saline solution, which may result in the formation of salt crystals. In turn, these salt crystals induce pressure on the pore walls. ...

Crack propagation in disordered materials How to decipher fracture surfaces

For a half-century, engineers know how to describe and predict thepropagation of a crack in a model elastic homogeneous medium. The case of real ma-terials is much more complex. Indeed, we do not know how to relate their lifetime ortheir resistance to their microstructure. To achieve such a prediction, understandingthe role of the microstructural disorder on the behavior of a cr...

Fracture of Dental Materials

Roughness of fracture surfaces

We study the fracture surface of three dimensional samples through a model for quasi-static fractures known as Born Model. In particular, we consider the roughness of this fracture surface. We find for the roughness exponent a value ζ = 0.5 expected for “small length scales” in microfracturing experiments. Since this corresponds to a slow evolution for the fracture, our simulations confirm that...

Characterize Porous Materials

■ Abstract Beam-based positron annihilation spectroscopy (PAS) is a powerful porosimetry technique with broad applicability in the characterization of nanoporous thin films, especially insulators. Pore sizes and distributions in the 0.3–30 nm range are nondestructively determined with only the implantation of low-energy positrons from a table-top beam. Depth-profiling with PAS has proven to be ...