Key Engineering Materials Vols. 594-595

Abstract: Applications of lightweight construction materials enable the design and construction in challenging, difficult and demanding scenarios. Construction materials with enhanced stiffness as in sandwich panels, large portable structures and floating foundations are examples of such materials. The advent of cellular structure technology has actively introduced innovation and enabled design and construction, meeting engineering requirements such as in the construction of the body of air crafts. Cellular mat structures present in the minimum, triple benefits in being lightweight, load sharing and minimising non-uniform deformation. This paper further explores the use of recycled plastic waste as the base material for an innovative geomaterial. The combination of cellular structure, mat structure and use of recycled waste material is a desirable development in manufacturing. Paper also outlines the techno social benefit of adopting such material in construction. Other application-specific benefits related to cellular mats are those like noise reduction, energy absorption, thermal insulation, mechanical damping. This paper specifically presents the development of a new multifunctional lightweight material is been proposed as an invective innovation for highway construction on challenging ground condition.

Abstract: The successfulness of a software development project is not only based on the tools and the technology used but also really depends on how the developed software meets the end user requirements. Involving end user as an active member of software development team, one of the popular agile methods known as eXtreme Programming (XP) had been selected as the software development methodology. This paper is focused on one of the main practices called on-site customer. The project under study is a web based Highway Construction Monitoring System (HIGHCONS). Challenges related to its implementation throughout the development process and also the suitable solutions in facing the challenges were also considered.

Abstract: The urgent need for a web opening in the pretensioned inverted T-beams after the construction for essential services causes local cracking around the opening which leads to decrease in stiffness and load carrying capacity. Therefore, strengthening the vicinity of the opening is essential to restore the loss in load carrying capacity of the beam using GFRP. To study the deflection of pretentioned inverted T-beam with web opening, three-dimensional finite element beam models are developed before and after GFRP strengthening using the finite element analysis (FEA). Modeling methodology and nonlinear analysis approach in ANSYS are presented. The results obtained from the FEA beam model are compared with the test data in terms of load-deflection curve. It has been concluded that FEA models are good representations for GFRP strengthened beams with web openings in terms of the number of elements, structural details, and, especially, reasonably accurate results in general.

Abstract: In this research the performance of ultrasonic pulse velocity in concrete is examined as a nondestructive experiment, in order to estimate compressive strength of thermally activated alum sludge multiple blended high performance concretes (HPC) that contain AAS, silica fume (SF), ground granulated blast furnace slag (GGBS) and palm oil fuel ash (POFA) are determined in both binary and ternary blends of cement. The water/binder ratio and total binder content are fixed at 0.30 and 493 kg/m3 for all types of mixes. The ultrasonic pulse velocity (UPV) of each concrete mix was measured using 100mm cubes after a curing period of ages of 3, 7, 28, 56 and 90 days. The results indicate a very positive exponential relationship between compressive strength and UPV for both binary and ternary blends of HPC mixtures, with coefficient correlation (R²) of 0.889.

Abstract: Millions tons of coal ash which constitute of fly ash and bottom ash were produced annually throughout the world. They were significant to be developed as masonry brick to substitute the existing widely used traditional material such as clay and sand brick which were produced from depleting and dwindling natural resources. In the present study, the coal ash from coal-fired thermal power plant was used as the main raw material for the fabrication of cementless unfired lightweight brick. The binder comprising of Hydrated Lime (HL)-activated Ground Granulated Blastfurnace Slag (GGBS) system at binding ratio 30:70, 50:50 and 70:30 were used to stabilize the coal ash in the fabrication process of the brick. Foam was used to lightweight the brick. The compressive strength and ambient density were evaluated on the brick. The results indicated that the brick incorporating HL-GGBS system achieved higher strength of 20.84N/mm² at 28 days compare to the HL system with strength of 13.98N/mm² at 28 days. However, as the quantity of foam increase at 0%, 25%, 50%, 75% and 100%, the strength and density for the brick decreased.

Abstract: Oil pocket has been reported that it may improve tribology characteristic and thus prolong the lifespan of the joint. In order to implement it on spherical surface, appropriate positioning system is required. This paper reports the investigation of three axes workpiece positioning system in order to machine oil pocket (micro-pits) on hip implant. A conventional linear x-y-z axes configuration (Cartesian coordinate) and two configuration of spherical coordinate (swing-swing and swing-rotate configuration) are applied in simulation. All machined workpiece are investigated in pits distribution, shape, and machined angle. The inspection concludes that spherical method with swing-rotate configuration is the most suitable method for machining oil pocket on spherical surface.

Abstract: The application of geopolymer as a coating was not widely explored by other researchers and therefore the study of kaolin based geopolymer coating applied on different types of clay substrate (unsintered and sintered) was carried out. The geopolymer coating paste were initially prepared by mixed the kaolin with alkaline activator (NaOH and Na₂SiO₃) until homogeneous mixture was obtained. After that, the geopolymer paste then applied on the surface of clay substrates and left to cure at 80°C for 24 hours and sintered at 800°C respectively for 2 hours. Flexural, compression test and SEM for morphology analysis are studied. Based on the results obtained, it shows that kaolin based geopolymer coating can contribute in improving the substrate strength, while curing and sintering temperature applied to the geopolymer coating on different substrate can influence the interaction between substrate and geopolymer paste to diffuse according to SEM image proved.

Abstract: The study presented in this paper is focused on the effect of surfaces roughness of pure aluminium A1100 on the cold work extrusion process by three different angles of taper die. Different angles of taper die will affect the surface roughness of the workpiece. To protect the surface and to reduce friction, lubricants are often used in extrusion process [1]. Different lubricants may have different optimum taper die angle that are suitable to be applied. Two types of materials used in this experiment are steel SKD 11 for taper die and aluminium A1100 for workpiece and different angles applied are 30^o, 45^o, and 60^o. Moreover, with respect to each angle, three different types of lubricants were used which are Daphne Draw S Series, Palm Olein, and EFB bio oil. The Universal Testing Machine and Surface Roughness Tester were used in this experiment. The result obtained from the experiment shows that at 30^o of taper die angle were producing the smooth product surfaces for each lubricant and Daphne Draw S Series could reduce the surface roughness compared to other lubricant test.

Abstract: TiAlBN nanocomposite coating have been successfully deposited on AISI 316 substrate via RF magnetron sputtering by varying nitrogen-to-total flow ratio (R_N) of 5, 15, 20, 25%, as well as varying substrate temperature of 100, 200, 300, and 400 oC; using single Ti-Al-BN hot-pressed target. Chemical compositions of the coatings were analysed using X-ray photoelectron spectroscopy (XPS). XPS results showed that the TiAlBN nanocomposite coating reaches a nitride saturated state at higher R_N (e.g 15, 20, and 25%) and boron concentration was found to be approximately 9 at.%. However, as the concentration of nitrogen decreases at lower R_N (5%), boron concentration was found to increase to 16.17 at. %_. This is due to the increase of TiB₂ phase in the coating. Variations of substrate temperatures were found to give no significant effect on the chemical composition of the deposited TiAlBN nanocomposite coating.

Abstract: In this paper, modeling of Titanium Nitrite (TiN) coating thickness using Response Surface Method (RSM) is implemented. Insert cutting tools were coated with TiN using Physical Vapor Deposition (PVD) sputtering process. N₂ pressure, Argon pressure and turntable speed were selected as process variables while the coating thickness as output response. The coating thickness as an important coating characteristic was measured using surface profilometer equipment. Analysis of variance (ANOVA) was used to determine the significant factors influencing TiN coating thickness. Then, a polynomial linear model represented the process variables and coating thickness was developed. The result indicated that the actual validation data fell within the 90% prediction interval (PI) and the percentage of the residual errors were low. Findings from this study suggested that Argon pressure, N₂ pressure and turntable speed influenced the TiN coating thickness.