Gro Markeset

Softening of concrete in compression — Localization and size effects

This paper presents a constitutive macromechanical model for concrete in compression. The model, named the Compressive Damage Zone (CDZ) model, is based on the hypothesis of compressive failure within a zone of limited length. In this damage zone, the failure mode is a combination of distributed axial splitting and localized deformation. Within the damage zone the post-peak behaviour is described by means of two curves, one related to the distributed splitting cracking and one to the localized deformation. The compressive strain caused by the axial splitting cracks is assumed to be proportional to the tensile fracture energy GF. It is shown through compressive tests of specimens of different length and width that the proposed failure hypothesis is realistic.

Ultra High Performance Concrete is Ideal for Protective Structures

Presented is the result of the work performed on the development of low cost ultra high performance concrete (UHPC) for protective structures. The UHPC was developed based on commonly available materials and at a reasonable cost, with workability suitable for traditional construction practice. Studies of the hardened properties of the concrete, in addition to full scale production test along with full scale impact test and large scale beam tests are included in the documentation program. The tests also indicate that the penetration resistance of UHPC is significantly better than for normal strength concrete.