Journal of Mechanical and Construction Engineering (JMCE)

Design and Construction of Bituminous Pavements

2022-11-06T16:28:55+00:00

The objective of pavement design is to develop pavement constructions in a way that stresses and strains within the constructions due to traffic and climatic conditions do not exceed certain limits, or – in other words – to design pavements, which are able to resist appearing loads during the intended life time. As failure due to fatigue is regarded as relevant for the determination of the thickness of the bituminous layers, several criteria exist to predict the technical life time on the basis of empirical observations of the fatigue behaviour in the laboratory or in full-scale tests. All these criteria have in common that relevant stresses or strains within the construction are considered, which appear, in general, either as tensile load at the bottom of the bituminous base course or as compressive load at the top of the subgrade. For bituminous layers, for example, single cracks emerging at the bottom of the base course and developing to the surface are regarded as relevant for the structural fatigue of the pavement. At the surface, these single cracks lead to so-called alligator cracking and, hence, decreasing bearing capacity of the pavement construction.

Research Article A Parametric Study to Improve the Heat Transfer of Solar Air Heater Through CFD Analysis

2022-12-25T17:28:58+00:00

In this article, we optimize the performance of a solar air heater (SAH) using two designs and computational fluid dynamics (CFD) analysis in this article. With the help of ANSYS fluent, two designs are considered to investigate the effect of different rib heights (e = 1, 1.2, 1.4, 1.6, and 1.8) and duct depths (h = 16, 18, 20, 22, and 24). The effects of dif-ferent parameters such as velocity, temperature, turbulence kinetic energy, and turbu-lence energy are compared to optimize the performance of designs 2 and 3. It is noticed that except temperature, all other parameters are on the lower side for design 2 as compared to design 3, due to improper air mixing in design 2. The authors presented the optimized design 3 with rib height e = 1.8 and depth of duct h = 16 after consideration of all the parameters (temperature, velocity, turbulence kinetic energy, and turbulence intensity) at various rib heights and depths of duct. These numerical results will serve as a benchmark for future research to improve the efficacy of solar air heaters.

Experimental Studies on Solar Chimney for Building Space Heating and Ventilation Enhancement: Energy, Exergy and Economic Analysis

2022-11-28T05:01:37+00:00

Solar chimneys are with or without heat storage widely used for improving the ventila-tion and thermal comfort in buildings. The energy, exergy, economic analysis of solar chimney and the CO2 mitigations (EEEC) are evaluated in this communication. The im-proved solar chimney with MS plate and MS box was designed and developed by the author in the CBRI Roorkee. The observations of typical day of December have been taken for the presentation and the whole month data have been used to evaluate the EEEC parameters. The maximum energy efficiency has been observed by 26.68% during 12 hours of the typical day, and at the same time the exergy efficiency has obtained 3.69%. Approximately 2285kWh energy can be saved during a year through solar chimneys. The payback period of an improved solar chimney with MS plate (SCWMSP) is estimated to be less than one year and with MS box (SCWMSB)) it is likely to be one year. CO2 can also be saved with the energy conservation parameter observed saving of 4.37 ton / year CO2 by SCWMSP, on the other hand if SCWMSB have implemented than CO2 would be save by 5.51 ton/year.

Application of Carbon Fibers in Construction

2022-11-06T16:22:57+00:00

Carbon fibers (also known as graphite fibers) are high-performance fibers, about five to ten micrometers in diameter, composed mainly of carbon, with high tensile strength. Plus, they are extremely strong with respect to their size. They have high elastic modulus in comparison with glass fiber. According to the working period, carbon fiber-reinforced polymers possess more potential than those with glass fiber. However, they are relatively expensive as compared to similar fibers, such as glass fiber, basalt fiber, or plastic fiber. Its high quality, light weight, and imperviousness to erosion, make it a perfect strength-ening material. Carbon fiber-reinforced composite materials are used to make aircraft parts, golf club shafts, bike outlines, angling bars, car springs, sailboat masts, and sev-eral different segments which need to have less weight and high quality.