bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of rainfall on the compaction of dense-graded hot mix asphalt
Authors: Ismail S , Hassan N A , Yaacob H , Warid M N M , Mashros N , Mohamed A , Hassan S A , Azahar N M 
Published: May 2019

Abstract
Unpredictable tropical weather particularly rainfall can possibly interfere the compaction work of asphalt pavement. Heavy rainfall often leads the asphalt to cool and harden quickly and become difficult to compact. This study evaluates the effect of rainfall on the compaction properties of hot mix asphalt (HMA). A dense-graded mix of AC14 was prepared using 60/70 PEN bitumen and compacted at different temperatures. A handy steel roller was used to compact the slab samples with the size of 305 mm × 305 mm × 50 mm. The cooling rate and time available for compaction (TAC) were monitored using thermocouple under different levels of artificial rainfall and wind speed generated in the laboratory to simulate the wet conditions. The slabs were then cored at 100 mm diameter and tested for the volumetric properties. The result shows that environmental conditions and mix temperature determines the cooling rate and final density of the asphalt pavement. In addition, the TAC decreases as the compaction temperature reduces. Alternatively, working under light and moderate rainfall during the asphalt paving operation reasonably achieves the required degree of compaction (DOC). However, paving works under heavy rainfall reduce TAC, compactibility and density of the asphalt mat.
Modification of emulsified bitumen using Styrene-Butadiene Rubber (SBR)
Authors: Jin T H , Warid M N M , Idham M K , Hainin M R , Yaacob H , Hassan N A , Ismail C R , Afiqah R N 
Published: May 2019

Abstract
This paper evaluates the performance of using different percentage of styrene-butadiene rubber (SBR) in rapid-setting emulsion (RS-2K). The polymer modified bitumen emulsions were blended at various percentages of SBR, i.e. 5%, 7%, 9%, 11% and 13%. The investigation focused on the optimum percentage of SBR added into the polymer modified bitumen emulsion and the performance of the polymer modified bitumen emulsion. There are several laboratory tests involved such as penetration test, softening point test and dynamic shear rheometer test that were done in order to determine the physical and rheological properties of bitumen emulsion. Based on the results, it shows that the physical properties of the polymer modified bitumen improved compared to unmodified bitumen emulsion. For rheological properties, by adding the SBR in the bitumen emulsion, the rutting resistance of the bitumen emulsion is improved. From the isochronal curve, the polymer modified bitumen emulsion shows improvement in the complex modulus, G* as comparing to unmodified bitumen emulsion. The optimum percentage of the SBR is 13% as it shows better performance compared to other percentages.
Performance evaluation of asphalt micro surfacing – a review
Authors: Usman K R , Hainin M R , Idham M K , Warid M N M , Yaacob H , Hassan N A , Azman M , Puan O C 
Published: May 2019

Abstract
In spite the fact that micro surfacing receives accolades by researchers of being the most cost-effective, environmentally friendly, and functionally viable pavement preventive maintenance amongst the various asphalt surface treatments (AST). However, there has not been a universally standardised mix design, acceptable material type, compatible polymer-binder combination, laboratory-field correlational performance tests, and its field dependency performance indicators. The requirements set by the International Slurry Surfacing Association (ISSA), Malaysian Jabatan Kerja Raya (JKR-public works department) and American Society for Testing and Materials (ASTM) are stated to be guides. This study brings to fore the challenges, methodologies adopted and successes recorded towards solving the aforementioned concerns by various researches globally from existing literatures with emphasis on material-type effects, mix design methodology, serviceability/environmental performance, incorporation of industrial wastes and emulsion-polymer compatibility amongst others in micro surfacing. Hence, the contents of relevant published journal articles, theses, academic and industrial reports published within the last two decades (1979 - 2019) that met the selection criteria aforementioned were critiqued. Result indicated improvement in key pavement surface functional performance parameters as a function of enhanced polymer(s) used in improving desired performance, type of aggregate and its gradation, pre-treatment condition and ultimately emulsion type. However, there is a lack of total consensus on the mix design, even though polymers are unanimously agreed by researchers to improve performance. Future advances in micro surfacing should focus on the use of industrial wastes, synthetic material and especially by-products from industrial processes.
Influence of bamboo pile clusters in the pile mattress bamboo construction systems as reinforcement of soft subgrade that support embankment load
Authors: Widodo B , Pratikso  , Rochim A , Irsyam M , Widoanindyawati V 
Published: May 2019

Abstract
One of the problems that arise in building land transport infrastructure located on soft soil is the making of the road construction. The completion of the road construction issue is carried out by the engineering that the road is safe and stable. The main long-term goal of this research is to provide a method of handling embankment construction that is above soft soil, complementing the existing methods, by using the main bamboo material. This study discussed the influence of bamboo pile clusters on a bamboo matrass construction system to support the embankment load on soft soil. The method of this research is to make a bamboo cluster containing 3 bamboo sticks, 4 bamboo sticks, and 7 bamboo sticks. The cluster is inserted into the soft soil. Bamboo pile clusters are gradually loaded until the soil collapses. Data that is investigated in the area of the cluster and the force given to suppress the cluster. The results of the study show the relationship of bamboo pile clusters with Pult. The value of the P

ult
depends on the area of the cluster with the formula: P

ult
= 840 L

n
(X) - 3044 with X = is the cluster area.
Reversible moisture damage in asphalt mixture
Authors: Arfat M , Yaacob H , Hassan N A , Warid M N M , Idham M K , Ismail C R , Nor H M , Hainin M R , Mohamed A , Mashros N , Yunus N Z M , Hassan S A , Jaya R P , Ayob M F 
Published: May 2019

Abstract
A moisture damage has been one of the major concerns for HMA pavement by loss of adhesion between bitumen and aggregate surface or loss of the cohesion within asphalt binder due to action of water. Water is the one of major contributor towards the damage of asphalt pavement. The aim of this research is to evaluate the effects of Moisture Damage (MD) towards the performance of asphalt mixture under different conditions (dry, wet and dry back). For this research laboratory fabricated specimens were conditioned in accordance to ASTM D4867 to achieve desire saturation level up to 80% and then immersed in water for different soaking period to simulate flooding scenario. Indirect Tensile strength (ITS) and Resilient Modulus (RM) tests were performed on moisture conditioned specimens at regular interval (1,3 and 5 days). After 5 days testing specimens were stored at room temperature for another 5 days to dry and were tested again to determine the recoverability of moisture damage. The results from this study indicated that tensile strength and modulus gradually decreased with the increasing of conditioning period, and upon drying at certain period specimens recovered 82% and 76% of initial ITS and RM respectively. The results suggested that moisture damage in asphalt mixture tested is reversible.
Improvement of CBR value in soil subgrade using garnet waste
Authors: Sani W. N. H. M. , Mohamed A. , Khalid N. H. A. , Nor H. M. , Hainin M. R. , Giwangkara G. G. , Hassan N. A. , Kamarudin N. A. S. , Mashros N. 
Published: May 2019

Abstract
This paper presents the findings on the improvement of California Bearing Ratio (CBR) value of soil subgrade using garnet waste. Soil subgrade are very important in construction of roadways and need more attention in strength. Many researchers found that soil subgrade in Malaysia need an improvement technique for the road constructions. One of the techniques is using garnet waste which is an industrial waste that is getting bulkier, and thus create opportunity to reduce and reuse the waste. The research aims to determine the properties of soil subgrade and garnet waste, to determine the CBR value of soil subgrade and to determine CBR value of soil subgrade mixed with garnet waste. Material properties testing for soil subgrade are sieve analysis and Atterberg limit; and garnet waste used sieve analysis and chemical composition. Compaction test in the mixed proportion are used to obtain the Optimum Moisture Content (OMC) and Maximum Dry Density (MDD) and CBR test was done using CBR-Marshall Tester. In this study, the result obtained from garnet waste have been used to observed their effect on CBR value of soil subgrade by varying the amount of garnet waste contain 20%, 40%, 60%, 80% and 100%. 100% garnet waste content showed the best result for the highest 43% CBR value. The CBR value of the soil showed judicious improvement after mixing with above 40% garnet waste in the soil subgrade. As a conclusion, the improvement of CBR value in soil subgrade using garnet waste is applicable.
Aberrant behaviour plausibility in road traffic violations, errors and lapses
Authors: Faiz R.U. , Mashros N. , Abbas H. Z. U. , Hassan S. A. 
Published: May 2019

Abstract
Road traffic crashes have been formidable concern for road safety engineer and different techniques have been applied to address such problems. Driving Behaviour is one of the pivotal issue that arises as in every country, state and region; though such issues play significant role in socio-economic development of country. The aim to conduct this study was to estimate driver traits and correlation between violation, errors, and lapses. Questionnaires are used to measure aberrant behaviour and its plausibility to be involved in road traffic crashes. A questionnaire was developed based on the Manchester Driving Behaviour Questionnaire to estimate the correlation. Data was collected from the capital city (Islamabad) of Pakistan. Statistical analysis was carried out to set up the correlation using the Pearson Correlation. It was estimated from the model results that violations are positively associated and correlated with lapses and errors. Lapses are positively associated and correlated to violations and errors. Errors are positively associated and correlated to lapses and violations.
Design concept of horse arena in Malaysia – A case study
Authors: Fadilah Darmansah Nur , Diana Tamjehi Sitti , Wafi Razali Abdul , Zaini Nadia , Syed Sahimi Sharifah Nur Farhana 
Published: May 2019

Abstract
One of the most important facilities required for any equine centre is horse arena. Horse arena is a place where horse doing the execrsice. Its a dedicated riding space is useful for training purposes. Equine Center may include an outdoor arena, indoor arena, or both. This paper presents the findings from a case study on the arena design concept throughout Malaysia. A total of fourtytwo (42) Equine Centre throughout the country were selected and visited in the study. The items studied include the types of arena, size of arena, material used for surface and fencing. The results indicated that about 79% of the arena used outdoor design, 31% of the arena had arena size of 20m x 60m, 56% used Polyvinyl Chloride (PVC) as the main material of fencing, and almost 74% used sand as types of surface in arena. Then for the indoor arena, the design concept of the roof structure was 79% used gable type of design with 81% used zinc as the roofing material. Generally, it can be said that the design concept of the horse arena in Malaysia depends on the owner needs, activities of the equine centre whether it is use for training or game.
Level-set modelling of Laser Beam Melting process applied onto ceramic materials – Comparison with experimental results
Authors: Chen Q. , Moniz Da Silva Sancho L. , Guillemot G. , Gandin Ch.-A. , Bellet M. , Bartout J.-D. , Berger M.-H. , Colin C. 
Published: May 2019

Abstract
Laser Beam Melting (LBM) processes benefit from significant progress in recent years. Currently, manufacturing of ceramic parts for applications at high temperature in aeronautical industries can be planned. However, understanding of defect formation is required in order to optimize manufacturing strategy. In this work, level-set modelling is proposed to simulate tracks development during LBM processes. Thermo-mechanical solution is performed in both powder and dense domains. Fluid flow is computed considering the surface tension and Marangoni forces. In addition mechanical resolution is achieved to investigate stress evolution in the rear part of the track. Applications are developed on alumina material. The influence of laser power, scanning velocity and physical properties are investigated and discussed. Validations of the heat source model are proposed by comparisons of melt pool dimensions and shapes with experimental measurements. A coherent evolution of the track morphology is shown when varying process parameters or material properties.
Thermo-mechanical simulation of track development in the Laser Beam Melting process - Effect of laser-metal interaction
Authors: Queva Alexis , Mayi Yaasin , Bellet Michel , Guillemot Gildas , Peyre Patrice , Dal Morgan , Moriconi Clara , Metton Charlotte 
Published: May 2019

Résumé
Interest has recently emerged for the manufacture of aeronautical parts by Laser Beam Melting (LBM) additive process. This energy efficient process can for instance be used to build complex geometries, which cannot be made with traditional processes. However, complex phenomena occur during powder melting and track development : vaporisation phenomena influence laser-matter interaction by creating metal vapours that are responsible for the reduction of absorbed energy. The recoil pressure generated by the vaporisation counteracts the surface tension between the melt pool and the inert gas, also inducing liquid instabilities. The study of laser-matter interaction and induced phenomena can help understand the origin of defects such as porosities or cracks. In this approach, a level-set modelling of the LBM process at a mesoscopic scale is proposed to follow melt pool evolution and track development during build. A volume heat source model is used for laser/powder interaction considering the material absorption coefficient. A surface heat source is used to take into account the high laser energy absorption by dense metal alloys. An energy solver is coupled with thermodynamic database and pre-determined solidification path. Shrinkage during consolidation from powder to liquid and compact medium is modelled by a compressible Newtonian constitutive law. An automatic remeshing adaptation is also used to save time and avoid high computational cost. In the future, the computation of multiple beads or the build of a wall in a context of lattice structures will have to be considered.
Solidification of niobium-silicide-based alloys during laser additive manufacturing process
Authors: Allen A. , Douglas A. C. , Feitosa L. M. , Qian H. , Li J. , Dong H. B. , Lin X. , Li Y. 
Published: May 2019

Abstract
Niobium silicide-based composites, in the application of gas turbine blades, promise significant efficiency improvements compared to current Ni-based alloys. The higher temperature capability would allow the engine to run at a higher temperature than that of current alloys, increasing engine efficiency. Nb-Si based composites possess a lower density, due to the presence of ceramic phases such as Nb5Si3 and/or Nb3Si. This would reduce the weight of the rotating blades. However, improvements in certain properties, such as room temperature toughness and oxidation resistance are needed.
This study focuses on the manufacturability aspect of the powder feeding laser additive manufacturing (LAM) process to engineering Nb-Si based alloy samples. LAM has the advantage of forming near-net shapes without the use of expensive cores and moulds for the reactive Nb-Si melt. Fine microstructure and even chemical composition distribution with reduced macro-segregation are obtained. With the use of power feeding system, new Nb-Si based alloys are LAMed with varying atomic composition. Microstructures of the LAMed alloys will be presented, and the relationship between the microstructure and the alloy chemistry will be reported.
Solidification cracking during welding of steel: In situ X-ray observation
Authors: Aucott L. , Li J. , Rack A. , Dong H. B. 
Published: May 2019

Abstract
Solidification cracking is an important issue during welding, casting and some of the additive manufacturing process. In order to illuminate the failure mechanisms, solidification cracking during arc welding of steel are investigated in situ with high-speed, high energy, synchrotron X-ray radiography approach. Analysis of the in situ radiography sequence revealed the solidification cracking initiates in the weld sub-surface trailing the welding electrode at relatively low true strain of about 3.1% in the form of micro-cavities. Although both material type and bending speed influence solidification cracking, cracks propagate from the core of the weld towards the free surface along the solidifying grain boundaries was found at a speed of between 1.7 - 2.6 × 10−3 m s−1 for three different steels. In addition, a three-stage mechanistic model for solidification cracking during welding of steel is proposed.
A 3D discrete-element model for simulating liquid feeding during dendritic solidification of steel
Authors: Feng Yi , Založnik Miha , Thomas Brian , Phillion André 
Published: May 2019

Abstract
A 3D meso-scale discrete-element model has been developed to simulate fluid flow during dendritic solidification of steel. The model domain is a representative volume element consisting of a set of equiaxed dendritic grain envelopes along with extra-dendritic liquid channels, where the final grain shape is given by a Voronoi tessellation. Solidification of each grain is simulated via a volume average approach. The output of the solidification simulation at a given solid fraction is used as the input mesh for the fluid flow simulation. A single domain Darcy-Brinkman model is used to calculate the pressure field within the liquid channels, with Poiseuille flow assumed to occur in the extra-dendritic region, and Darcy flow assumed to occur within the dendrite envelope. Mass conservation over each element is then used to derive a flow equation that is solved via the finite element method. The results of this new model are first compared with a previously-developed granular model [1] where fluid flow only occurs between the grains, and then compared with different forms of the Carman-Kozeny equation. It is shown that the intra-dendritic liquid fluid flow plays a major role in the semi-solid pressure field, and thus needs to be included when investigating hot tearing susceptibility in engineering alloys undergoing dendritic solidification.
Effect of the Coriolis force on the macrosegregation of aluminum in the centrifugal casting of Ti-Al alloys
Authors: Cisternas Fernández M. , Založnik M. , Combeau H. , Huang C. , Zollinger J. , Hecht U. 
Published: May 2019

Abstract
Within the framework of the ESA GRADECET project, experiments of directional solidification of cylindrical Ti-Al samples were conducted in hypergravity. The experiments were performed in a centrifuge with the apparent gravity (sum of centrifugal and terrestrial gravity) aligned along the cylinder centerline. 3D numerical simulations of aluminum macrosegregation in these samples are presented. A volume-averaging solidification model is used that accounts for centrifugal and Coriolis accelerations in a non-inertial rotating reference system. We compare the melt flow pattern and the macrosegregation formation under terrestrial gravity and under

20

g
→

centrifugation. The results show that the Coriolis acceleration, although very weak, breaks the symmetry of the thermosolutal convection, having an important impact on the final macrosegregation pattern. The macrosegregation is entirely modified in comparison with a sample solidified under terrestrial gravity conditions. Besides the aluminum segregation intensity increases with the centrifugation level.
Prediction of solidification structures in a 9.8 t steel ingot
Authors: Gerin Benjamin , Combeau Hervé , Založnik Miha , Poitrault Isabelle , Cherif Maya 
Published: May 2019

Abstract
The control of the carbon macrosegregation level in steel ingots is important for the structural integrity of the final component. During solidification, the fragmentation of the columnar dendrites is an important source of equiaxed grains, and has a large influence on the macrosegregation and the grain structure. The goal of this study is to show that a numerical model that takes into account fragmentation can describe the formation of the structures and the macrosegregation during solidification of a large steel ingot. The present article describes the multiphase numerical model used in the simulations. The simulation results are compared to experimental data from a 9.8 t ingot cast in A5/6 steel by ArcelorMittal Industeel. The model can then be used to explain the formation of the observed structures. For example, we show that the structural transitions, first from columnar to equiaxed globular and then to equiaxed dendritic at the bottom of the ingot are a consequence of the concurrent transport and growth of the dendrite fragments from the columnar zone. Furthermore, we show that most of the structures are formed very early on during solidification, whereas macrosegregation develops much more gradually.
Optimization of ultrasonic cavitation processing in the liquid melt flow
Authors: Subroto T , Eskin D G , Tzanakis I , Lebon G S B. , Miranda A , Pericleous K. 
Published: May 2019

Abstract
Ultrasonic processing (USP) during direct-chill (DC) casting of light metal alloys is typically applied in the sump of a billet. This approach, though successful for structure refinement and modification, has two main drawbacks: (a) mixture of mechanisms that rely heavily on dendrite fragmentation and (b) a limited volume that can be processed by a single ultrasonic source. We suggest moving the location of USP from the sump to the launder and applying it to the melt flow for continuous treatment. The apparent benefits include: (a) degassing of the melt volume, (b) grain refinement through activation of non-metallic inclusions, fragmentation of primary crystals, and deagglomeration of grain refining substrates, and (c) a possibility to use a single ultrasonic source for processing large melt volumes. To optimize this process with regard to the acoustic intensity and melt residence time in the active cavitation zone, flow modification with baffles as well as informed location of the ultrasonic source are required. In this paper, we demonstrate the results of experimental trials where the degassing degree and grain refinement have been the indicators of the USP efficiency for two aluminium alloys, i.e. LM25 and AA7050. The results are supported by acoustic measurements and computer simulations.