Engineering Journal of Research and Development

PERFORMANCE OF RAILWAY BALLAST IMPROVED WITH TIRE-DERIVED AGGREGATE UNDER CYCLIC LOADING

2024-09-16T10:33:44+07:00

The deterioration of ballasts is caused by abrasion and crushing under the dynamic load of the train until they break into powder. This eventually causes the need to clean or replace the ballast. This research focuses on a study to improve the ballast layer by partially replacing the ballast with recycled tire-derived aggregate (TDA). Because of its elastic properties, tire scraps are an alternative for research. The laboratory testing series was conducted, consisting of the physical properties test of ballast, design, and construct the ballast box test. The ballast and TDA were prepared with different TDA as 5%, 10%, and 15% (by volume of ballast) and performed under cyclic loading. Finally, an optimum TDA content was suggested to decrease the ballast deterioration. The result found that in the case of ballast mixed with TDA, the ballast breakage values have a decrease trend with mixed TDA of 5% and an increase trend when TDA is more than 5%. The strength behavior of the ballast layer is described by the vertical settlement, vertical stress, stiffness, and damping ratio values, it was found that when the ballast layer is loaded, plastic deformation will occur rapidly up to approximately 1,000 cycles, after which the rate of settlement will gradually decrease when the load reaches approximately 10,000 cycles, and then it will remain stable with almost constant settlement. Considering the deterioration pattern and strength behavior of the ballast layer, it was found that using recycled TDA in the ballast layer in an amount not exceeding 15% by volume of ballast that can be moved and rearranged appropriately can significantly reduce the deterioration of the ballast track.

Strength Development of Sugar Cane Bagasse Ash Stabilized by Cement for Road Construction Works

2024-09-30T23:30:15+07:00

This study investigated the development of compressive strength of sugar cane bagasse ash (SCA) mixed with cement. Sugar cane bagasse ash is the by-products from sugar industry. In this study, the material SCA was brought from Sugar Power Plant Company Limited. The set of modified compaction of SCA mixed with cement at 2% upto 10% were performed. The compaction results showed that the maximum dry density (MDD) was measured between 1,335 kg/m³ and 1,490 kg/m³ and the average amount of optimum water content of 25% was reported. This amount of water content at 25% was to be used in preparing specimens for unconfined compression tests (UCS tests). The strength tests included the SCA specimens mixed with cement at 4%, 6%, 8% and 10% with the curing periods of 7 days, 14 days and 28 days. As a results of cementation by hydration of cement and water, the UCS test results showed that the strength increased with increasing the amount of cement and curing periods. At the certain amount of cement, this study proposed the relationship between the values of unconfined compressive strength (q_u) and curing time (t). Also, with the cement content at least 6% at the curing age of 7 days, the test results showed that the specimens had strength more than 7 kg/cm² satisfying the requirement for subbase course. However, specimens with the cement content of 4% required the curing period at least 21 days to develop the strength upto 7 kg/cm² for the subbase course. In addition, the results suggested the use of 10% cement content at the curing time of 28 days to satisfy the strength at 17.5 kg/cm² according to the DOH standard for the base course materials. Therefore, the study results recommended that SCA mixed with cement be the materials with values added for civil engineering works with the potential to be used as material substitution for road constructions.

ASSESSMENT OF FLOOD HAZARD AREAS USING ANALYTICAL HIERARCHY PROCESS IN THE YANG RIVER BASIN

2024-11-04T14:44:20+07:00

The Yang River basin is also an area that is prone to repeated flooding. The main causes are the terrain downstream, which is the plain area, and the low drainage capacity of the river. When there is a large amount of water during the rainy season, it causes the water to overflow the banks and flood the community and agricultural areas, causing damage. The purpose of this study was to assess the flood hazard of the lower basin using the Analytical Hierarchy Process (AHP) combined with the Geographic Information System (GIS) to analyze six factors: elevation, land use, slope, soil permeability, average annual rainfall, and repeated flood. The results of the study will be a flood-risk map. It is divided into 5 risk levels: very low flood risk area of 4.929 sq. km. (14.078%), low flood risk area of 4.222 sq. km. (12.059%), medium flood risk area of 6.098 sq. km. (17.417%), high flood risk area of 9.706 sq. km. (27.722%), and very high flood risk area of 10.057 sq. km. (28.724%), respectively. The analysis results show that flood risk areas in 16 sub-districts (Bueng Kluea Sub-district, Selaphum District, Roi Et Province) have the highest flood risk areas, most of which are community and agricultural. The results of the analysis can be used to plan water management in the region to cope with flood problems.

A STUDY OF SEASONAL IONOSPHERIC DISTURBANCES IN THAILAND USING GPS DATA DURING 2023

2024-11-05T15:25:59+07:00

The ionosphere is a layer of Earth's atmosphere that plays a crucial role in communication and Global Navigation Satellite System (GNSS) positioning. The free electrons within this layer can affect the propagation of radio signals, leading to distortions or signal loss. Therefore, studying ionospheric disturbances is essential for the development of communication systems and satellite-based surveying and mapping. This research investigated ionospheric disturbances in Thailand using GNSS data from 12 Continuously Operating Reference Stations (CORS) managed by the Royal Thai Survey Department in 2023. Results indicate that the disturbance of the ionosphere in Thailand is correlated with both region and season. The highest variability in Total Electron Content (TEC) and Rate of Total Electron Content index (ROTI) was observed in the northern region and during the summer. Furthermore, the highest ROTI disturbance often occurred between 7:00 PM and 11:00 PM. These findings can be applied to identify periods with varying levels of ionospheric disturbance in Thailand and to study their impact on GNSS positioning accuracy.

ANALYSIS OF CORS POSITION TIME SERIES AND VELOCITIES USING PRECISE POINT POSITIONING IN THAILAND

2024-11-22T15:59:34+07:00

This research studies the movement behavior of Continuously Operating Reference Stations (CORS) in Thailand by analyzing time series data, velocity, and directional changes of station coordinates over time. Additionally, it examines the impact of CORS station displacement rates on the long-term closure accuracy of the CORS triangulation network. The study processes GPS satellite signal data from CORS stations within the RTK GNSS Network, covering the period from 2019 to 2023—five years. With precise point positioning (PPP) techniques using the GipsyX research software. The findings reveal that CORS stations in Thailand exhibit continuous southeastward movement at an average azimuth angle of 106° 29' 42.4" and an average velocity of 29 mm/year, with the most pronounced change occurring along the E-axis, followed by the N and U axes, additionally. Based on the maximum deviation over the next 30 years from Epoch 2024.0, the displacement of CORS stations significantly affects the closure accuracy of the CORS triangular network across most areas in Thailand. Compared to FGCS standards for satellite survey work, the impact falls within class A for 59.47% of the area, class AA for 25.95%, and class B for 10.40%. The results demonstrate that the CORS stations in Thailand maintain consistent velocity and directional movement patterns, significantly impacting positional closure discrepancies over time. This behavior also reflects tectonic movements in the region. Failure to account for these factors during data analysis could lead to inaccurate results.

DEVELOPMENT OF A TOOL FOR TESTING THE SUNLIGHT AND WEATHER RESISTANCE OF RUBBER AND PLASTIC IN OUTDOOR ENVIRONMENTS

2024-09-17T12:45:12+07:00

This abstract is concerning the Development of a Tool for Testing the Resistance of Rubber and Plastics to Sunlight and Weathering in Outdoor Environments for providing a convenient method for evaluating the degradation of these materials. This tool records weather factors that contribute to the deterioration of rubber and plastic materials under real-world conditions. The testing service complies with the preparation of test samples based on Industrial Product Standard (TIS) 2377-2559 (2016) for rubber flooring sheets, aimed at evaluating the properties of rubber and plastic materials. The test results include visual documentation of surface degradation on test samples at a magnification of 2x (2×) compared to a scale bar, along with weather data recorded over an 8-week testing period. For instance, the tests on natural rubber traffic cones conducted by the Office of Scientific Instrument and Testing at Prince of Songkla University reported weather data, including temperature, humidity, sample surface temperature, UV intensity index, light intensity, and solar energy levels during the testing period. Environmental measurements demonstrated acceptable error margins compared to calibrated reference instruments, ensuring reliable and satisfactory results. Data recording and access are simple and fast, available anytime through a web browser on a computer or smartphone connected to the internet. Additionally, this testing tool serves as a cost-effective alternative for businesses, reducing expenses compared to the QSUN Accelerated Weathering Tester, an expensive imported scientific instrument. The developed tool can fulfill specific testing and reporting requirements, providing an efficient, customizable solution for evaluating the durability of rubber and plastic materials.

PROPORTION ANALYSIS OF POLYPROPYLENE SCRAP FOR INJECTION MOLDING OF THERMOPLASTIC PARTS OF ELECTRICAL APPLIANCES

2024-10-04T18:03:15+07:00

Polypropylene scrap, which is considered to be waste, frequently remains behind in the injection molding process of thermoplastic parts. Various plastic industries are interested in recycling to reduce environmental problems. The objective of this research was to analyze the proportion of polypropylene scrap that had undergone the injection molding process and pure polypropylene that still had suitable properties for injection molding into thermoplastic parts of electrical appliances. The independent variables of interest were ratio of polypropylene scrap fraction to pure polypropylene and the number of rounds of polypropylene scrap that had undergone the injection molding process. For the response variables, they were mechanical properties of thermoplastic. The acceptable recycled thermoplastic must meet mechanical criteria including the izod impact strength was greater than 126 Joule per meter (J/m), the tensile strength at yield point was greater than 23.4 megapascal (MPa) and the elongation at yield point was greater than 6.30 percent (%). The results of the study found that 1) polypropylene scrap that had undergone the injection molding process after 1 round could be used up to 50 percent by weight, 2) polypropylene scrap that had undergone the injection molding process after 2 rounds could be used up to 30 percent by weight, and 3) polypropylene scrap that had undergone the injection molding process after 3 rounds could be used up to 10 percent by weight.