சிவில் மற்றும் சுற்றுச்சூழல் பொறியியல் இதழ்

Estimating the service life of Reinforced Concrete (RC) bridge structures located in corrosive marine environments of a great importance to their owners/engineers. Traditionally, bridge owners/engineers relied more on subjective engineering judgment, e.g. visual inspection, in their estimation approach. However, because financial resources are often limited, rational calculation methods of estimation are needed to aid in making reliable and more accurate predictions of the service life of RC structures. This is in order to direct funds to bridges found to be the most critical. Criticality of the structure can be considered either from the Structural Capacity (i.e. Ultimate Limit State) or from Serviceability viewpoint whichever is adopted. This paper considers the service life of the structure only from the Structural Capacity viewpoint. Considering the great variability associated with the parameters involved in the estimation process, the probabilistic approach is most suited. The probabilistic modelling adopted here used Monte Carlo simulation technique to estimate the Reliability (i.e. Probability of Failure) of the structure under consideration. In this paper the authors used their own experimental data for the Correlation Length (CL) for the most important deterioration parameters. The CL is a parameter of the Correlation Function (CF) by which the spatial fluctuation of a certain deterioration parameter is described. The CL data used here were produced by analyzing 45 chloride profiles obtained from a 30 years old RC bridge located in a marine environment. The service life of the structure was predicted in terms of the load carrying capacity of an RC bridge beam girder. The analysis showed that the influence of SV is only evident if the reliability of the structure is governed by the Flexure failure rather than by the Shear failure.

In a small temperature range, at temperatures below the temperature sufficient for the passability of the electronic cloud of atoms that make up a solid in vacuum experiments, a “fusion” could occur between the atom that characterizes the solid and the atom or ion that composes the gas. The procedure must be performed in a vacuum with the help of Special Forces, including the pressure force of a piston, the increase in the power of the natural kinetic energy of the gas using suitable instrumentation, harmonic oscillations of the filter, and other forces to be applied about the specific experiment to be carried out. The merger between the atom constituting the filter, and the atom formatting the gas could lead the system with its complex mechanism of energies and forces to opt for the minimum energy configuration. It i.e., could happen that the two nuclei of the two atoms merge. In this way, a change in the state of matter could occur; even the crystalline form of the solid could change. If the gas consisted of hydrogen atoms, the atom constituting the solid after this transformation could increase its atomic number by changing its state of matter even in its crystalline lattice shape. Some application hypotheses are the transformation of Boron into one of the various forms of Carbon and the change of Silicon into black phosphorus.

The study was aiming to investigate the effect of partial replacement of cement by cattle bone ash (CBA) in a concrete property. Complete silicate analysis of CBA shows that the material has high calcium oxide content (43.26%) which is the major oxide compound of cement. A C-25 concrete grade was selected for this study. The Normal consistency, setting time, soundness of cement paste, slump, compressive strength and density of concrete tests are done with (0%), 5%, 10%, 15% and 20% cement replacement with cattle bone ash. The compressive strength of concrete was done by curing 15 cm × 15 cm × 15 cm cube concrete specimens underwater for 3,7,28 and 56 days. The normal consistency of the cement paste increases as the percentage of the cattle bone ash increases in the paste attributed to high water absorption of CBA than OPC. The initial and final setting time of cement paste increase as the percentage of replacement of cement with bone ash. The slump of concrete decreases at 0% to 10% CBA mix and increases in 15% to 20% CBA mix. From the results, the partial replacement of Ordinary Portland Cement with Bone ash shows a gradual decrease in the compressive strength of concrete. The concrete density decreases as the percentage of bone ash increases. The use of cattle bone waste as an additive or supplementary cementing material production has vital importance to produce low-cost concrete and helps to conserve materials needed for cement production.