română PERFORMANCE OF TITANIUM GYPSUM-REPLACED MAGNESIUM CHLORIDE-MAGNESIUM OXYCHLORIDE COMPOSITE MATERIALS
SHUREN WANG, LINRU ZHAO, JIAN GONG, YAN WANG
Abstract
To realize the resourceful utilization of solid waste and develop novel building materials, an experimental study was conducted using titanium gypsum, magnesium chloride, and magnesium oxide as raw materials to prepare test samples. The samples underwent a series of tests, including unconfined compressive strength testing, water absorption analysis, dynamic non-contact full-field strain measurement, scanning electron microscopy, and X-ray diffraction, to investigate the effects of varying titanium gypsum substitution rates for magnesium chloride on the strength, failure modes, and microstructural properties of the resulting composite materials. Results show that as the substitution rate of titanium gypsum increases, the dry density of the composites initially increases and then decreases, while the water absorption rate continues to rise, with a particularly notable increase observed at substitution rates between 10% and 25%. Both flexural and compressive strengths exhibit an initial increase followed by a decrease, reaching their optimal values at a 5% substitution rate, with a maximum improvement of 17.37% in flexural strength and 18.81% in compressive strength. The increase in titanium gypsum substitution rate alters the phase morphology and internal density of the composites, confirming the feasibility of substituting magnesium chloride with titanium gypsum in magnesium oxychloride cement. This substitution strategy not only promotes the utilization of solid waste but also contributes to cost savings, highlighting its potential for practical applications.
Keywords
magnesium oxychloride cement, titanium gypsum, mechanical properties, microstructural analysis
MANI P, ARULARASAN R
Abstract
One of the biggest obstacles to using natural fibers in industrial applications is their poor mechanical qualities. The study aims to use carbon and glass fillers to increase the flexural, impact, and tensile strengths of luffa/epoxy composites. Three fillers proportions (5wt.%, 7.5wt.%, 10wt.%) and one luffa proportion (20wt.%) were taken to fabricate the composites. The ASTM guidelines were followed when conducting the experiments. The fillers enhanced the composites tensile, flexural, and impact strengths. Comparing carbon-filled composites to corresponding glass-filled composites, the former showed superior performance. The 7.5wt.% carbon-filled composite shows the highest tensile and impact strength values, whereas the composite without fillers shows the lowest tensile and impact strength values. For flexural strength, 10wt.% carbon-filled composite shows the highest values, whereas the composite without fillers shows the lowest values.
Keywords
luffa fiber, carbon filler, glass filler, tensile strength, impact strength, flexural strength
S. DHANALAKSHMI, T. JESUDAS, M. PRADEEP KUMAR
Abstract
The objective of this research study is focused to improve the wear resistance of the reinforced Al6063 hybrid metal matrix composite. The secondary particles like Al2O3 /TiO2are used as a reinforcement particle and the samples fabricated using stir casting technique with the base material Al6063 alloy. The fabricated samples were analyzed using Energy Dispersive Spectroscopy (EDS) and Scanning Electron Microscope (SEM) for understanding the potential of fabricated samples. Dry sliding wear test was conducted for the composite samples. The major wear process parameters such as load, sliding distance were considered for analysis work. The reinforcement particles such as Al2O3 /TiO2 also were considered as one of process parameter for wear analysis. The results of Variance of analysis clearly statethat reinforced secondary particles were the most influencing wear process parameter. The validation of desirability function analysis results reveals that the obtained optimal solutions were effectively enhance the wear resistance property for fabricated hybrid metal matrix composite (Al6063/Al2O3 /TiO2).
Keywords
Al 6063, Al2O3 /TiO2, DFA, Wear, RSM.
CHIENTA CHEN, SHINGWEN TSAI
Abstract
The rapid increase in terrain variability, climatic factors, axle load, and traffic volume has significantly affected the performance of asphalt pavements on expressways, particularly in harsh environmental conditions. In some cases, the service life of expressway pavements is far shorter than the expected design time. Certain sections of expressways face pavement failures just one or two years after opening, including cracks, potholes, rutting, and oil flooding. These problems not only disrupt the normal flow of traffic but also substantially increase maintenance and repair costs. This study focuses on diagnosing and addressing the causes of asphalt pavement failures, specifically in Jiangsu Province, China, where various asphalt pavement diseases were reported in 2020. By calculating the porosity of asphalt mixtures, we assess the water permeability, strength, and durability of the materials. Applying Mohr-Coulomb theory, we evaluate the high-temperature shear strength of asphalt mixtures and analyze rutting depth. Our findings indicate that rutting is the primary distress type on expressways in Jiangsu, with a rut depth of [3-8] mm observed in 67% of the total road network. Additionally, the pavement smoothness of expressways remains within a range of 0.5-1m/km for 85% of the highway network. We also analyze lateral and longitudinal fractures, which constitute 97% of repairs, with transverse cracks becoming prevalent after 6 years of service under high axle loads. This suggests the need for early preventive measures within the first 6 years of service to mitigate the development of cracks.
Keywords
asphalt pavement, highway, pavement diagnosis, repair technology, environmental impact, rutting, crack formation, traffic load.