Research on Chloride Penetration Resistance of Hybrid Fiber Reinforced Self-Compacting Concrete
The properties of chloride penetration of hybrid fiber reinforced self-compacting concrete (SCC) were investigated in this study. The results show that the chloride penetration resistance of concrete can be improved by single incorporation either carbon or cellulose fibers. The concrete chloride diffusion coefficient DRCM of 12-cm length carbon SCC with fiber content of 1.7, 2.72, and 3.4 kg/m3 decreases by 10.3, 25.5, and 18.2% compared to reference concrete without any fibers, respectively. Moreover, the concrete chloride diffusion coefficient DRCM of cellulose SCC with fiber content of 1.2, 1.6, and 2.0 kg/m3 decreases by 18.8, 22.4, and 26.7% compared to reference concrete, respectively. Based on the results of orthogonal experimental design, the chloride diffusion coefficients DRCM of hybrid fiber reinforced SCC are listed in order of importance, as follows: length of carbon fiber > content of carbon fiber > content of cellulose fiber; furthermore, the hybrid of 2.72-kg/m3 carbon fiber with length of 12 mm and 2.0-kg/m3 cellulose fiber exhibits the most significant effect on chloride diffusion coefficients DRCM of SCC.
On the mechanical properties and fracture behavior of polyolefin fiber-reinforced self-compacting concrete
Abstract Fiber-reinforced self-compacting concrete uses the flowability of concrete in fresh state to improve fiber orientation, in due course enhancing toughness and energy absorption capacity. In the past few years there has been a boost in the development of concretes with macro-synthetic fibers added. In this paper the mechanical properties of a self-compacting concrete with low, medium and high-fiber contents of macro polyolefin fibers are studied. Their fracture behavior is compared with a plain self-compacting concrete and also with a steel fiber-reinforced self-compacting concrete. The results obtained showed that a polyolefin fiber-reinforced self-compacting concrete has fracture properties analogous to a steel fiber-reinforced self-compacting concrete. Furthermore, it is possible to fit this behavior within the existing standards requirements. Dispersion obtained for fracture mean values among the different amounts was analyzed by using a fracture surface analysis and the amount and distribution of fibers.
Researches on Structural Factor Involvement in Oral Tribology
This study is focused on two ceramic materials, D.SING (Ivoclar) and VM13 (emphasis the VITA TN), frequently used in restorative dentistry practice and it comes to complete a full set of results obtained by the authors over several years of research on oral tribology with main influence on oral health. In this way there are involved more specific structural aspects of dental restorative ceramic materials quality as is shown in [1].