Long-term Test Arrangement for Externally Strengthened Reinforced Concrete Elements

Methods for external strengthening of concrete use elements of very high tensional strength glued on to its tensioned surface. These elements may be of metal, carbon fibers (CFRP), glass fibers or others, usually having very good mechanical properties. However, these high-strength elements are normally attached to concrete by epoxy resins. Epoxy resins have a low Young`s modulus and therefore a higher rate of creep may have an influence on the long-term behavior of such external strengthening. In order to verify this idea experimentally a special space-saving arrangement of tests is described in this paper. Panels act as loaded beams but simultaneously as a load for the other panels in a stand. The different load magnitude acting on a different layer of panels should make it possible to study the long-term influence of the degree of shear force on the glue creep. Certainly, the glue creep may be dependent on the type of epoxy resin; therefore several epoxy resin types are included in the tests

NANOINDENTATION TEST FOR DLC COATING ANALYSIS

Resume In this report the effects of the substrate on the microhardness of Diamond like carbon (DLC) thin films were investigated. The DLC coatings were deposited by Radio Frequency Plasma Actived Chemical Vapor Deposition (RF PACVD; 13,56 MHz) process on three mechanically polished substrates, which were chosen for comparison; hardened molybdenum high speed steel AISI M2, unhardened tool steel AISI L2 and titanium alloy TiAl6V4. The aim of the present investigation was to determine the influence of substrates on microhardness and other mechanical properties of DLC layer. These properties especially microhardness were studied and compared from nanoindentation load -displacement curves. Results show that the hardness of the substrate is the crucial value for the hardness of the DLC films

The Study of DLC and Si-DLC Based Coatings and Their Mechanical Properties

In this paper, diamond-like carbon (DLC) films and DLC-Si films were studied. These films were deposited by DC-plasma-assisted chemical vapour deposition (PACVD). X-ray diffraction analysis of coatings was used for a determination of coatings structure. In particular, the effect of the crystal structure of the coatings on their mechanical properties was studied