Comparative study on Steel fibre reinforced Cum control concrete under flexural and deflection
Fibre reinforced concrete, a composition of concrete and fibres is being prominently used for various important applications. The hook tain steel fibres assist in controlling the propagation of micro-cracks present in the matrix, first by improving the overall cracking resistance the matrix and later by bridging across even smaller cracks formed after the application of load on to the member thereby preventing there widening into major cracks. In the present paper, the effect of steel fibre reinforcement with different percentage of fibre 0, 1%, 2% and 3% by volume for M-40 grade of concrete with aspect ratio 50, 60 and 67 are studied. The beam is tested for flexural strength. The percentage increase through utilization of steel fibers is reported. A relationship between aspect ratio vs. flexural strength represented graphically.
STEEL FIBERS AS REPLACEMENT OF WEB REINFORCEMENT FOR RCC DEEP BEAMS IN SHEAR
Test data are presented on the shear strength of a series of reinforced cement concrete (RCC) deep beams with three steel fiber volume fractions (0, 1.0 and 1.25%), three shear span toeffective depth ratios (0.75, 1.0 and 1.25) and three combinations of web reinforcement. A total of 18 beams were tested to failure under two-point top loading. The test results indicate that the fibers have significant influence on the shear strength of a longitudinally reinforced concrete beams. Shear strength increases with increasing fiber volume and decreasing shear span to-effective depth ratio. Steel fibers can replace the conventional web reinforcement in RCC deep beams.
Numerical tools applied to power reactor noise analysis
In order to be able to calculate the space- and frequency-dependent neutron noise in real inhomogeneous systems in two-group theory, a code was developed for the calculation of the Green's function (dynamic transfer function) of such systems. This paper reports on the development as well as the test and application of the numerical tools employed. The code that was developed yields the space-dependence of the fluctuations of the neutron flux induced by fluctuating properties of the medium in the two-group diffusion approximation and in a two-dimensional representation of heterogeneous systems, for both critical systems and non-critical systems with an external source. Some applications of these tools to power reactor noise analysis are then described, including the unfolding of the parameters of the noise source from the induced neutron noise, measured at a few discrete locations throughout the core. Other concrete applications concern the study of the space-dependence of the Decay Ratio in Boiling Water Reactors, the noise-based estimation of the Moderator Temperature Coefficient of reactivity in Pressurized Water Reactors, the modeling of the beam- and shell-mode core-barrel vibrations in Pressurized Water Reactors, and the investigation of the validity of the point-kinetic approximation in subcritical systems driven by an external source. In most of these applications, calculations performed using the code are compared with at-power plant measurements. Power reactor noise analysis applications of the above type, i.e. core monitoring without disturbing plant operation, is of particular interest in the framework of the extensive program of power uprates worldwide.