Tag Archives: Properties

Investigation on the Interrelationship between the Chemical Composition, Heat Treatment Parameters and the Phase Transformation Process, Microstructure Evolution and the Mechanical Properties of Austempered Steel (Published)

The interrelationship between chemical composition, heat treatment parameters, and phase transformation, microstructural evolution and the mechanical properties of austempered steel was studied. Two samples of steel with different percentage composition of carbon of 0.56 and 0.76 were used for the study. They were austentized at the respective temperatures of 8000C, 8400C, 9000C and 9600C for 30 minutes. They were thereafter quenched using bitumen-palm kernel oil, and subjected to austempering isothermal heat treatment at 4200Cfor different time durations of 5, 15, 30, 45 and 60 minutes. The samples were tested for tensile strength, elongation, hardness and impact strength. They were also subjected to microstructural characterization to determine the phases in the microstructures and their effects on the properties of the developed materials. Results obtained revealed that the dominant phases in the microstructure were bainite, matensite and traces of retained austenite. It was found that decreasing austenitizing temperature yields finer grain structures with increase in tensile strength and elongation with decrease in hardness and relatively little effect on the impact strength. At any given austenitizing temperature, shorter austempering holding time yielded optimum properties in tensile strength and elongation while higher hardness values were associated with shorter holding time. These results proved that the process conditions have strong correlation with both the microstructures and the mechanical properties. It was concluded that the most promising microstructures with respect to excellent strength-ductility property are those obtained at the ausenitizing temperature range of 800 -8400C for the austempering time range of 5 – 30 minutes. These materials have potential for load bearing application while those austenitized within the range of 900 – 9600C using austempering time range of 5 – 15 minutes are candidate material for wear resistant application.

Keywords: Austempering, Austenitize, Composition, Heat treatment, Microstructure, Properties

Analysis of the Water Absorption Properties by using Polystyrene Sanded Concrete (Published)

In this paper, an evaluation of the mechanical and hydrothermal characteristics of a polystyrene sanding lightweight concrete was studied. Mechanical properties are evaluated from a density point of view. Hydrothermal characteristics use water absorption as a measurement. In this study, 30% EPS was used to replace natural coarse aggregates and produce lightweight concrete. It is economical and practical and meets the criteria required for lightweight concrete. The bulk density of the concrete and oven dry density was obtained at 1789 KN / m 3 and 1674 kg / m 3, but the total water absorption and absorption of capillary water increased with suction time. The high water absorption rate at the start of the test has an appropriate capillary steepness coefficient in the same period. The relationship between the amount of water absorption Q per unit sample area and the capillary coefficient K is that when the amount of water absorption increases, the capillary coefficient and the rate of variation are both represented by the correlation coefficient R2. Moisture capacity is 6.9%. All laboratory tests are carried out by standard practice standards. The significance of this research is that innovative technology is adapted to modify and improve the construction industry process, thereby improving the environment that is sustainable, industrial waste management, and cheaper and more economical construction. When 30% of the coarse aggregate is exchanged, the density and absorption of water from the produced concrete is within the allowable range. Therefore, Polystyrene Sanded Concrete can be used for the manufacture of lightweight concrete that performs the required functions with this replacement level.

Keywords: Analysis, Properties, Water, absorption, polystyrene, sanded concrete

Estimating The Reinstatement Or Replacement Cost In Valuation: A Case for the Estate Surveyor and Quantity Surveyor to Work in Tandem in Perfecting Valuation Briefs When Using the Contractor’s Method (Depreciated Replacement Cost Method) In Determining the Value of Properties (Published)

This paper seeks to highlight the need for Estate Surveyors and Valuers in Nigeria to improve on their current cost estimation techniques when valuing non-rent yielding and specialized properties using the DRC method of valuation and most importantly engage the services of Quantity Surveyors in ensuring that accurate cost estimates are provided for use in the valuation process. The research methodology adopted in actualizing the aim of this work made use of primary and secondary sources of data which included questionnaires and oral interviews. The measurement analysis of data made use of statistical tables and simple percentages. The postulated hypotheses on the other hand was tested and analyzed using the chi-square Statistic technique with a significance level of 5% (0.05). The findings showed that indeed there was a dearth of information on the part of Estate Surveyors and Valuers when it came to the knowledge and use of current cost estimating methods when valuing properties using the DRC method of valuation. These findings also highlighted the fact that the services of Quantity Surveyors most times are not commissioned when these cost estimates are to be determined for valuation, hence leading most times to properties being undervalued or overvalued. In a nutshell, the recommendations postulated dwelt on improving the cost estimating knowledge of Estate Surveyors and Valuers through seminars, symposiums and workshops organized by NIESV and NIQS, awareness of the need for Valuers to work with Quantity Surveyors to perfect valuation briefs involving the use of the DRC method and changes made to the curriculum of the study of the course Estate Management in tertiary institutions.

Keywords: Depreciated Replacement Cost, Estate Surveyors, Properties, Quantity Surveyors, Valuation

Secondary Products of Petrochemistry in Production of Bitumen Emulsions (Published)

Today, the most important tasks of petroleum processing and petrochemistry are provision of a deep processing of heavy oil raw materials and rational use of wastes and secondary products. One of the directions on effective use of heavy tonnage and at the same time deficit binding material as a bitumen is a wide introduction of bitumen emulsions in water into the road and civil construction practice. In addition to the advantages of bitumen, as an organic binding material, the bitumen emulsions have a number of positive properties, for example more less viscosity in the temperature interval from 0 to 1000С and higher cohesion degree with a rock material surface. One of the most important quality indicators of the bitumen emulsions is their decomposition rate, in accordance with which the emulsions are classified as quick-, mid- and slow-breaking, EBC 1, 2, 3 relatively. In recent years, the most important direction of petroleum processing and petrochemistry is investigation of intensification ways of oil raw material processing and rational use of target and secondary products with optimization of their qualitative features. In solution of these problems, the tasks on development, justification of principles and processing methods, focused on obtaining of products with specified properties are highlighted. In this context, secondary products of a one-staged isoprene synthesis, which do not find rational use to the moment, are of interest. Based on the one-staged isoprene synthesis chemical composition analysis, we can suppose that its use in production of bitumen emulsions will favor to obtaining of the product with specified properties. In this connection, investigations, focused on the use of one-staged isoprene synthesis as a modifier of the bitumen emulsions, are of present interest. The paper presents experimental data on estimation of the secondary products different content effect on the bitumen emulsions’ rheological properties.

Keywords: Bitumen Emulsion, Modifier, Properties, Secondary Products