One of the applications of tether system is in the field of satellite
technology, where the mother ship and satellite equipment are connected
with a cable. In order to grasp the motion of this kind of tether system
in detail, the tether can be effectively modeled as flexible body and
dealt by multibody dynamic analysis. In the analysis and modeling of
flexible body of tether, large deformation and large displacement must
be considered. Multibody dynamic analysis such as Absolute Nodal
Coordinate Formulation with an introduction of the effect of damping
force formulation can be used to describe the motion behavior of a
flexible body. In this study, a parameter identification technique via
an experimental approach is proposed in order to verify the modeling
method. An example of swing-up control using the genetic algorithm
control approach is performed through simulation and experiment. The
validity of the model and availability of motion control based on
multibody dynamics analysis are shown by comparison between numerical
simulation and experiment.
For long time, Sn-Pb solder alloys have been used extensively as the main interconnection materials in the soldering. It is no doubt that Sn-Pb offers many advantages including good electrical conductivity, mechanical properties as well as low melting temperature. However, Pb is very toxic and Pb usage poses risk to human health and environments. Owing to this, the usage of Pb in the electronic industry was banned and restricted by the legislation. These factors accelerate the efforts in finding suitable replacement for solder alloy and thus lead-free solder was introduced. The major problems associated with lead-free solder is the formation of large and brittle intermetallic compound which have given a rise to the reliability issues. Micro alloying with Sb seems to be advantageous in improving the properties of existing lead-free solder alloy. Thus, this paper reviews the influence of Sb addition to the lead-free solder alloy in terms of microstructure formations and thermal properties.
Center of Excellence Geopolymer & Green Technology (CeGeoGTech), Faculty of Chemical Engineering Technology, Universiti Malaysia Perlis (UniMAP), Taman Muhibbah, 02600 Jejawi, Arau, Perlis, Malaysia
Geopolymer is synthesized by polycondensation of SiO4 and AlO4 aluminosilicate complexes, tetrahedral frames linked with shared sialate oxygen. This paper studies the effect of the solids-to-fluids (S/L) and Na2SiO3/NaOH proportions on the preparing of metakaolin inorganic membrane geopolymer. By consolidating a mixture of metakaolin with sodium hydroxide, sodium silicate and foaming agent, the geopolymer membrane was made in required shape about 1 cm and cured at 80°C for 24 hours. After the curing process, the properties of the samples were tested on days 7. Sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) solution were utilized as an alkaline activator with a NaOH fixation fixed at 10 M. The geopolymer inorganic membrane tests were set up with various S/L proportions (0.8, 1.0, 1.2 and 1.4) and Na2SiO3/NaOH proportions (0.5, 1.0, 1.5, 2.0 and 2.5). Aluminium (Al) powder as a foaming agent was used to create bubbles in porous structure and provide details on the development of membrane geopolymers. This metakaolin membrane, based on the geopolymer, was synthesized by a suspension that depends on the fast cementing mechanism of high-temperature slurries. Porous geopolymeric circles provided a homogeneous composition and quantitative distribution of pores. The water absorption, density, impact toughness testing and microstructure analyses were studied. However, considering the promising results, an adjustment in the mix design of the metakaolin inorganic membrane geopolymer mixtures could increase their mechanical properties without negatively affecting the mechanical properties and porosity, making these sustainable materials a suitable alternative to traditional porous cement concrete.
The introduction of carbon nanotubes (CNTs) onto glass fibre (GF) to create a hierarchical structure of epoxy laminated composites has attracted considerable interest due to their merits in improving performance and multifunctionality. Field emission scanning electron microscopy (FESEM) was used to analyze the woven hybrid GF-CNT. The results demonstrated that CNT was successfully deposited on the woven GF surface. Woven hybrid GF-CNT epoxy laminated composites were then prepared and compared with woven GF epoxy laminated composites in terms of their tensile properties. The results indicated that the tensile strength and tensile modulus of the woven hybrid GF-CNT epoxy laminated composites were improved by up to 9% and 8%, respectively compared to the woven hybrid GF epoxy laminated composites.
This paper discussed the effect of the addition of silica fume (2 wt.% and 4 wt.%) and alumina (2 wt.% and 4 wt.%) on the properties of fly ash geopolymer concrete. The fly ash geopolymer concrete achieved the highest 28-day compressive strength with 2 wt.% of silica fume (39 MPa) and 4 wt.% of alumina (41 MPa). The addition of 2 wt.% of silica fume increased the compressive strength by 105% with respect to the reference geopolymer (without additive). On the other hand, the compressive strength surged by 115% with 4 wt.% of alumina compared to the reference geopolymer. The addition of additives improved the compactness of the geopolymer matrix according to the morphology analysis.
Centre of Excellence Geopolymer and Green Technology (CEGeoGTech), Universiti Malaysia Perlis (UniMAP), 01000 Perlis, Malaysia
Faculty of Mechanical Engineering Technology, Universiti Malaysia Perlis (UniMAP), 02600 Perlis, Malaysia
Faculty of Chemical Engineering Technology, Universiti Malaysia Perlis (UniMAP), 01000 Perlis, Malaysia
Reactor Technology Center, Technical Support Division, Malaysian Nuclear Agency, Bangi, 43000 Kajang, Malaysia
Department of Electrical & Electronic Engineering, Lee Kong Chian Faculty of Engineering & Science, Universiti Tunku Abdul Rahman, Bandar Sungai Long, 43000 Kajang, Malaysia
S. Luhar, T.W. Cheng, D. Nicolaides, I. Luhar, D. Panias, and K. Sakkas, “Valorisation of glass wastes for the development of geopolymer composites—Durability, thermal and microstructural properties: A review,” Constr. Build. Mater., vol. 222, pp. 673–687, 2019.
K. Zulkifly et al., “Elevated-Temperature Performance, Combustibility and Fire Propagation Index of Fly Ash-Metakaolin Blend Ge- opolymers with Addition of Monoaluminium Phosphate (MAP) and Aluminum Dihydrogen Triphosphate (ATP),” Materials, vol. 14, p. 1973, 2020.
S. Hasani, P. Rezaei-Shahreza, A. Seifoddini, and M. Hakimi, “Enhanced glass forming ability, mechanical, and magnetic properties of Fe41Co7Cr15Mo14Y2C15B6 bulk metallic glass with minor addition of Cu,” J. Non-Cryst. Solids, vol. 497, pp. 40–47, 2018.
J. Zhou, W. Yang, C. Yuan, B. Sun, and B. Shen, “Ductile FeNi-based bulk metallic glasses with high strength and excellent soft magnetic properties,” J. Alloys Compd., vol. 742, pp. 318‒324, 2018.
M. Nabiałek et al., “Relationship between the shape of X-ray diffraction patterns and magnetic properties of bulk amorphous alloys Fe65Nb5Y5+xHf5–xB20 (where: 0, 1, 2, 3, 4, 5),” J. Alloys Compd., vol. 820, p. 153420, 2020.
S. Chen et al., “Elevated-temperature tensile deformation and fracture behavior of particle-reinforced PM 8009Al matrix composite,” Bull. Pol. Acad. Sci. Tech. Sci., vol. 69, no. 5, p. e138846, 2021, doi: 10.24425/bpasts.2021.138846.
S. Berdowska, J. Berdowski, and F. Aubry, “The relationship between the structural anisotropy of the PFA polymer/compressed expanded graphite-matrix composites and acoustic emission characteristics,” Bull. Pol. Acad. Sci. Tech. Sci., vol. 69, no. 5, p. e138235, 2021, doi: 10.24425/bpasts.2021.138235.
M. Mikuśkiewicz, “Silicon nitride/carbon nanotube composites: preparation and characterization,” Bull. Pol. Acad. Sci. Tech. Sci., vol. 69, no. 5, p. e138234, 2021, doi: 10.24425/bpasts.2021.138234.
L. Sozańska-Jędrasik, W. Borek, and J. Mazurkiewicz, “Mechanisms of plastic deformation in light high-manganese steel of TRIPLEX type,” Bull. Pol. Acad. Sci. Tech. Sci., vol. 69, no. 5, p. e137412, 2021, doi: 10.24425/bpasts.2021.137412.
A. Zieliński, R. Wersta, and M. Sroka, “Analysis of the precipitation process of secondary phases after long-term ageing of S304H steel,” Bull. Pol. Acad. Sci. Tech. Sci., vol. 69, no. 5, p. e137520, 2021, doi: 10.24425/bpasts.2021.137520.
K. Pawlik, “Structure and properties of suction-cast Pr-(Fe, Co)-(Zr, Nb)-B rod magnets,” Bull. Pol. Acad. Sci. Tech. Sci., vol. 69, no. 5, p. e138971, 2021, doi: 10.24425/bpasts.2021.138971.
S. Lesz, B. Hrapkowicz, K. Gołombek, M. Karolus, and P. Janiak, “Synthesis of Mg-based alloys with rare-earth element addition by means of mechanical alloying,” Bull. Pol. Acad. Sci. Tech. Sci., vol. 69, no. 5, p. e137586, 2021, doi: 10.24425/bpasts.2021.137586.
B. Hrapkowicz, S. Lesz, M. Kremzer, M. Karolus, and W. Pakieła, “Mechanical alloying of Mg-Zn-Ca-Er alloy,” Bull. Pol. Acad. Sci. Tech. Sci., vol. 69, no. 5, p. e137587, 2021, doi: 10.24425/bpasts.2021.137587.
A.M. Țițu, A.B. Pop, M. Nabiałek, C.C. Dragomir, and A.V. Sandu, “Experimental modeling of the milling process of aluminum alloys used in the aerospace industry,” Bull. Pol. Acad. Sci. Tech. Sci., vol. 69, no. 5, p. e138565, 2021, doi: 10.24425/bpasts.2021.138565.
M. Staszuk et al., “Investigations of TiO2, Ti/TiO2, and Ti/TiO2/Ti/TiO2 coatings produced by ALD and PVD methods on Mg-(Li)-Al- RE alloy substrates,” Bull. Pol. Acad. Sci. Tech. Sci., vol. 69, no. 5, p. e137549, 2021, doi: 10.24425/bpasts.2021.137549.
R. Szklarek et al., “High temperature resistance of silicide-coated niobium,” Bull. Pol. Acad. Sci. Tech. Sci., vol. 69, no. 5, p. e137416, 2021, doi: 10.24425/bpasts.2021.137416.
T. Tański, W. Smok, and W. Matysiak, “Characterization of morphology and optical properties of SnO2 nanowires prepared by electrospinning,” Bull. Pol. Acad. Sci. Tech. Sci., vol. 69, no. 5, p. e 137507, 2021, doi: 10.24425/bpasts.2021.137507.
Institute of Metallurgy and Materials Science Polish Academy of Science, ul. Reymonta 25, 30-059 Kraków, Poland
Faculty of Materials Science and Engineering, Gheorghe Asachi Technical University of Iasi, 71 D. Mangeron Blvd., 700050 Iasi, Romania
Faculty of Chemical Engineering Technology, Universiti Malaysia Perlis (UniMAP), 01000 Perlis, Malaysia
Institute of Physics, Czestochowa University of Technology, ul. Dabrowskiego 69, 42-201 Czestochowa, Poland
Department of Engineering Materials and Biomaterials, Silesian University of Technology, ul. Konarskiego 18A, 44-100, Gliwice, Poland
Sieć Badawcza Łukasiewicz – Instytut Metalurgii Żelaza im. Stanisława Staszica, (Łukasiewicz Research Network – Institute for Ferrous Metallurgy), ul. K. Miarki 12-14, 44-100 Gliwice, Poland
The one-part geopolymer binder was synthesis from the mixing of aluminosilicate material with solid alkali activators. The properties of one-part geopolymers vary according to the type and amount of solid alkali activators used. This paper presents the effect of various sodium metasilicate-to-sodium aluminate (NaAlO2/Na2SiO3) ratios on fly ash-based one-part geopolymer. The NaAlO2/Na2SiO3 ratios were set at 1.0 to 3.0. Setting time of fresh one-part geopolymer was examined through Vicat needle apparatus. Mechanical and microstructural properties of developed specimens were analysed after 28 days of curing in ambient condition. The study concluded that an increase in NaAlO2 content delayed the setting time of one-part geopolymer paste. The highest compressive strength was achieved at the NaAlO2/Na2SiO3 ratio of 2.5, which was 33.65 MPa. The microstructural analysis revealed a homogeneous structure at the optimum ratio. While the sodium aluminium silicate hydrate (N-A-S-H) and anorthite phases were detected from the XRD analysis.
This paper reports on the flexural properties of thin fly ash geopolymers exposed to elevated temperature. The thin fly ash geopolymers (dimension = 160 mm × 40 mm × 10 mm) were synthesised using12M NaOH solution mixed with designed solids-to-liquids ratio of 1:2.5 and Na2SiO3/NaOH ratio of 1:4 and underwent heat treatment at different elevated temperature (300°C, 600°C, 900°C and 1150°C) after 28 days of curing. Flexural strength test was accessed to compare the flexural properties while X-Ray Diffraction (XRD) analysis was performed to determine the phase transformation of thin geopolymers at elevated temperature. Results showed that application of heat treatment boosted the flexural properties of thin fly ash geopolymers as the flexural strength increased from 6.5 MPa (room temperature) to 16.2 MPa (1150°C). XRD results showed that the presence of crystalline phases of albite and nepheline contributed to the increment in flexural strength.
For ages, concrete has been used to construct underwater structures. Concrete laying underwater is a very complex procedure important to the success or failure of underwater projects. This paper elucidates the influence of alkali activator ratios on geopolymers for underwater concreting; focusing on the geopolymer concrete synthesized from fly ash and kaolin activated using sodium hydroxide and sodium silicate solutions. The geopolymer mixtures were designed to incorporate multiple alkali activator ratios to evaluate their effects on the resulting geopolymers’ properties. The fresh concrete was molded into 50 mm cubes in seawater using the tremie method and tested for its engineering properties at 7 and 28 days (curing). The control geopolymer and underwater geopolymers’ mechanical properties, such as compressive strength, water absorption density, and setting time were also determined. The differences between the control geopolymer and underwater geopolymer were determined using phase analysis and functional group analysis. The results show that the geopolymer samples were optimally strengthened at a 2.5 alkali activator ratio, and the mechanical properties of the control geopolymer exceeded that of the underwater geopolymer. However, the underwater geopolymer was determined to be suitable for use as underwater concreting material as it retains 70% strength of the control geopolymer.
Setting time in geopolymers is known as the time taken for the transition phase of liquid to solid of the geopolymer system in which is represented in the initial setting and final setting. Setting time is significant specifically for application in the construction field. This study intends to determine the setting time of high calcium fly ash geopolymers and the properties of the geopolymers after setting (1-day age). This includes the determination of heat evolved throughout geopolymerization using Differential Scanning Calorimeter. After setting properties determination includes compressive strength and morphology analysis at 1-day age. High calcium fly ash was used as geopolymer precursor. Meanwhile, for mixing design, the alkali activator was a mixture of sodium silicate and sodium hydroxide (concentration varied from 6M-14M) with a ratio of 2.5 and a solid-to-liquid ratio of 2.5. From this study, it was found that high calcium fly ash geopolymer with 12M of NaOH has a reasonable setting time which is suitable for on-site application as well as an optimal heat evolved (–212 J/g) which leads to the highest compressive strength at 1-day age and no formation of microcracks observed on the morphology. Beyond 12M, too much heat evolved in the geopolymer system can cause micro-cracks formation thus lowering the compressive strength at 1-day age.
Optimal parameters setting of injection moulding (IM) machine critically effects productivity, quality, and cost production of end products in manufacturing industries. Previously, trial and error method were the most common method for the production engineers to meet the optimal process injection moulding parameter setting. Inappropriate injection moulding machine parameter settings can lead to poor production and quality of a product. Therefore, this study was purposefully carried out to overcome those uncertainty. This paper presents a statistical technique on the optimization of injection moulding process parameters through central composite design (CCD). In this study, an understanding of the injection moulding process and consequently its optimization is carried out by CCD based on three parameters (melt temperature, packing pressure, and cooling time) which influence the shrinkage and tensile strength of rice husk (RH) reinforced low density polyethylene (LDPE) composites. Statistical results and analysis are used to provide better interpretation of the experiment. The models are form from analysis of variance (ANOVA) method and the model passed the tests for normality and independence assumptions.
Geopolymer is widely studied nowadays in various scope of studies. Some of the ongoing studies are the study of the various materials towards the geopolymer strength produced. Meanwhile, some of the studies focus on the mixing of the geopolymer itself. This paper discussed the phase analysis of metakaolin/dolomite geopolymer for different solid to the liquid ratio which was, 0.4, 0.6, 0.8, and 1.0, and the properties that affected the geopolymer based on the phases. The constant parameters in this study were the percentage of metakaolin and dolomite used. The metakaolin used was 80% meanwhile dolomite usage was 20%. Besides that, the molarity of NaOH used is 10M and the alkaline activator ratio used is 2.0. All the samples were tested at 28 days of curing. The results show that the 0.8 solid to the liquid ratio used gave better properties compare to other solid to liquid ratio. The phases analyzed were quartz, sillimanite, mullite, and faujasite. The 0.8 S/L ratio shows the better properties compared to others by the test of phase analysis, compressive strength morphology analysis, and functional group analysis.
Universiti Malaysia Perlis (UniMAP), Faculty of Engineering Technology, P. O. Box 77, d/a Pejabat, Pos Besar, 01007 Kangar, Perlis, Malaysia
Universiti Malaysia Perlis (UniMAP), Centre of Excellence Geopolymer and Green Technology, School of Material Engineering, P. O. Box 77, d/a Pejabat, Pos Besar, 01007 Kangar, Perlis, Malaysia
This study summarised the recent achievement in developing fiber reinforced geopolymer concrete. The factor of replacing Ordinary Portland Cement (OPC) which is due to the emission of carbon dioxide that pollutes the environment globally is well discussed. The introduction towards metakaolin is presented. Besides, the current research trend involved in geopolymer also has been reviewed for the current 20 years to study the interest of researchers over the world by year. Factors that contribute to the frequency of geopolymer research are carried out which are cost, design, and the practicality of the application for geopolymer concrete. Besides, the importance of steel fibers addition to the geopolymer concrete is also well discussed. The fundamental towards metakaolin has been introduced including the source of raw material, which is calcined kaolin, calcined temperature, chemical composition, geopolymerisation process, and other properties. Alkali activators which are mixing solution between sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) have been reviewed. The mechanical properties of fibers reinforced metakaolin-based geopolymer concrete which is compressive and flexural are thoroughly reviewed. The compressive and flexural strength of fiber-reinforced metakaolin geopolymer concrete shows some improvement to the addition of steel fibers. The reviews in this field demonstrate that reinforcement of metakaolin geopolymer concrete by steel fibers shows improvement in mechanical performance.
Geopolymer is formed from the alkali activation of materials rich in Si and Al content with the addition of a silicate solution to enhance the properties of the materials. This paper presents research on the mechanical properties of fly ash-based geopolymer filler in epoxy resin by varying different solid to liquid ratios using sodium hydroxide and sodium silicate as the alkaline activator. However, the common problem observed from the solid to liquid ratio is the influence of curing time and compressive strength of geopolymer to have the best mechanical property. The mix design for geopolymers of solid to liquid ratio is essential in developing the geopolymer’s mechanical strength. A series of epoxy filled with fly ash-based geopolymer materials with different solid to liquid ratio, which is prepared from 0.5 to 2.5 solid to liquid ratio of alkaline activator. The tensile strength and flexural strength of the epoxy filled with fly ash-based geopolymer materials is determined using Universal Testing Machine under tensile and flexural mode. It was found that the optimum solid to liquid ratio is 2.0, with the optimum tensile and flexural strength value. However, both the tensile and flexural properties of epoxy filled with fly ash-based geopolymer suddenly decrease at a 2.5 solid to liquid ratio. The strength is increasing with the increasing solid to liquid ratio sample of geopolymer filler content.
Universiti Malaysia Perlis, Center of Excellence Geopolymer & Green Technology (CEGeoGTech), School of Materials Engineering, (UniMAP), 02600 Jalan Kangar-Arau, Perlis, Malaysia
Universiti Malaysia Perlis, (UniMAP), Faculty of Mechanical Engineering Technology, Perlis, Malaysia
Universiti Malaysia Terengganu, Faculty of Ocean Engineering Technology and Informatic, 21030 Kuala Nerus, Terengganu Darul Iman, Malaysia
Universiti Malaysia Perlis, (UniMAP), Faculty of Chemical Engineering Technology, 02600 Jalan Kangar-Arau, Perlis, Malaysia
Sriwijaya University, Civil Engineering Department, Faculty of Engineering, Indonesia
This paper elucidated the potential of electron backscatter diffraction analysis for ground granulated blast furnace slag geopolymers at 1000°C heating temperature. The specimen was prepared through the mechanical ground with sandpaper and diamond pad before polished with diamond suspension. By using advanced technique electron backscatter diffraction, the microstructure analysis and elemental distribution were mapped. The details on the crystalline minerals, including gehlenite, mayenite, tobermorite and calcite were easily traced. Moreover, the experimental Kikuchi diffraction patterns were utilized to generate a self-consistent reference for the electron backscatter diffraction pattern matching. From the electron backscatter diffraction, the locally varying crystal orientation in slag geopolymers sample of monoclinic crystal observed in hedenbergite, orthorhombic crystal in tobermorite and hexagonal crystal in calcite at 1000°C heating temperature.
Universiti Malaysia Perlis (UniMAP), Geopolymer & Green Technology, Centre of Excellence (CEGeoGTech), Perlis, Malaysia
Universiti Malaysia Perlis (UniMAP), Faculty of Chemical Engineering Technology, Perlis, Malaysia
National Metal and Material Technology Center (MTEC), National Science and Technology Development Agency (NSTDA), 114, Thailand Science Park, Pahonyothin Rd., Khlong 1, Khlong Luang, Pathum Thani 12120, Thailand
Department of Civil Engineering Technology, Faculty of Engineering Technology, Universiti Malaysia Perlis (UniMAP), 02100 Padang Besar, Perlis, Malaysia
Gheorghe Asachi Technical University of Iasi, Faculty of Materials Science and Engineering, 700050, Iasi, Romania
This paper details the properties, microstructures, and morphologies of the fly ash-based alkali-activated material (AAM), also known as geopolymers, under various steam curing temperatures. The steam curing temperature result in subsequent high strengths relative to average curing temperatures. However, detailed studies involving the use of steam curing for AAM remain scarce. The AAM paste was prepared by mixing fly ash with an alkali activator consisting of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH). The sample was steam cured at 50°C, 60°C, 70°C, and 80°C, and the fresh paste was tested for its setting time. The sample also prepared for compressive strength, density, and water absorption testings. It was observed that the fastest time for the fly ash geopolymer to start hardening was at 80°C at only 10 minutes due to the elevated temperature quickening the hydration of the paste. The compressive strength of the AAM increased with increasing curing time from 3 days to 28 days. The AAM’s highest compressive strength was 61 MPa when the sample was steam cured at 50°C for 28 days. The density of AAM was determined to be ~2122 2187 kg/m3, while its water absorption was ~6.72-8.82%. The phase analyses showed the presence of quartz, srebrodolskite, fayalite, and hematite, which indirectly confirms Fe and Ca’s role in the hydration of AAM. The morphology of AAM steam-cured at 50°C showed small amounts of unreacted fly ash and a denser matrix, which resulted in high compressive strength.
This paper presents an experimental investigation on the mechanical properties and microstructure of geopolymer repair materials mixed using fly ash (FA) and concrete substrates. An optimal combination of FA and concrete substrate was determined using the compressive test of geopolymer mortar mixed with various concrete substrate classes. It was found that the contribution of (C35/45) concrete substrates with the FA geopolymer mortar increases the 28-day bonding strength by 25.74 MPa. The microstructure analysis of the samples using scanning electron microscopy showed the denser structure owing to the availability of high calcium and iron elements distribution. These metal cations (Ca2+ and Fe3+) are available at OPC concrete substrate as a result from the hydration process reacted with alumina-silica sources of FA and formed calcium aluminate silicate hydrate (C-A-S-H) gels and Fe-bonding linkages.
In this study, the electrospray deposition (ESD) method was used to deposit carbon nanotubes (CNT) onto the surfaces of carbon fibers (CF) in order to produce hybrid carbon fiber-carbon nanotubes (CF-CNT) which is rarely reported in the past. Extreme high-resolution field emission scanning electron microscopy (XHR-FESEM), high-resolution transmission electron microscopy (HRTEM) and x-ray photoelectron spectroscopy (XPS) were used to analyse the hybrid carbon fiber-carbon nanotube (CF-CNT). The results demonstrated that CNT was successfully and homogenously distributed on the CF surface. Hybrid CF-CNT was then prepared and compared with CF without CNT deposition in terms of their tensile properties. Statistically, the tensile strength and the tensile modulus of the hybrid CF-CNT were increased by up to 3% and 25%, respectively, as compared to the CF without CNT deposition. The results indicated that the ESD method did not cause any reduction of tensile properties of hybrid CF-CNT. Based on this finding, it can be prominently identified some new and significant information of interest to researchers and industrialists working on CF based products.
This paper details a finite element analysis of the behaviour of Si-Al geopolymer concrete beam reinforced steel bar under an impulsive load and hyper velocity speed up to 1 km/s created by an air blast explosion. The initial torsion stiffness and ultimate torsion strength of the beam increased with increasing compressive strength and decreasing stirrup ratio. The study involves building a finite element model to detail the stress distribution and compute the level of damage, displacement, and cracks development on the geopolymer concrete reinforcement beam. This was done in ABAQUS, where a computational model of the finite element was used to determine the elasticity, plasticity, concrete tension damages, concrete damage plasticity, and the viability of the Johnson-Cook Damage method on the Si-Al geopolymer concrete. The results from the numerical simulation show that an increase in the load magnitude at the midspan of the beam leads to a percentage increase in the ultimate damage of the reinforced geopolymer beams failing in shear plastic deformation. The correlation between the numerical and experimental blasting results confirmed that the damage pattern accurately predicts the response of the steel reinforcement Si-Al geopolymer concrete beams, concluded that decreasing the scaled distance from 0.298 kg/m3 to 0.149 kg/m3 increased the deformation percentage.
Dolomite can be used as a source of aluminosilicate to produce geopolymers; however, this approach is limited by its low reactivity. This study analyzes the viability of producing geopolymers using dolomite/fly-ash with sodium silicate and NaOH solutions (at multiple concentrations) by determining the resultant geopolymers’ compressive strengths. The dolomite/fly-ash-based geopolymers at a NaOH concentration of ~22 M resulted in an optimum compressive strength of 46.38 MPa after being cured for 28 days, and the SEM and FTIR analyses confirmed the denser surface of the geopolymer matrix. The synchrotron micro-XRF analyses confirmed that the Ca concentration exceeded that of Si and Mg, leading to the formation of calcium silicate hydrate, which strengthens the resulting geopolymers.
In Eurocode 5, the stiffness equation for bolted steel-wood-steel is stated as a function ofwood density and fastener diameter only. In this research, an experimental study on various configurations of tested bolted steel-wood-steel (SWS) connections has been undertaken to predict the initial stiffness of each connection. In order to validate the Eurocode 5 stiffness equation, tests on 50 timber specimens (40 glued laminated timbers and 10 laminated veneer lumbers (LVL)) with steel plates were undertaken. The number of bolts was kept similar and the connector diameter, timber thickness, and wood density were varied. The results obtained in the experimental tests are compared with those obtained from the Eurocode 5 stiffness equation. From the analysis, it is signified that the stiffness equation specified in Eurocode 5 for bolted SWS connections does not adequately predict the initial stiffness. The results from Eurocode 5 stiffness equation are very far from the experimental values. The ratio of stiffness equation to experimental results ranges from 3.48 to 4.20, with the average at 3.77, where the equation overpredicted the experimental stiffness value for the connection. There is a need to consider or incorporated other parameters such as geometric configurations in Eurocode 5 stiffness equation to improve the ratio with the experimental data.
University Malaysia Perlis, Faculty of Civil Engineering Technology, 02600 Arau Perlis, Malaysia
2Sustainable Environment Research Group (SERG), Centre of Excellence Geopolymer and Green Technology (CEGeoGTech), University Malaysia Perlis (UniMAP), 01000 Kangar Perlis, Malaysia
University of Auckland, Faculty of Civil Engineering, Department of Civil and Environmental Engineering, Auckland, New Zealand
Department of Civil Engineering, College of Engineering, University Malaysia Pahang, 26300 Gambang Kuantan, Pahang Malaysia
Czestochowa University of Technology, Czestochowa, Poland
Centre of Excellence Geopolymer and Green Technology (CEGeoGTech), University Malaysia Perlis (UniMAP), 01000 Kangar Perlis, Malaysia
Sustainable Environment Research Group (SERG), Centre of Excellence Geopolymer and Green Technology (CEGeoGTech), University Malaysia Perlis (UniMAP), 01000 Kangar Perlis, Malaysia
University Malaysia Perlis, Faculty of Chemical Engineering Technology, 02600 Arau Perlis, Malaysia
Division of Materials Processing Technology and Computer Techniques in Materials Science, Silesian University of Technology, 44-100 Gliwice, Poland
With the rapid development of industry, abundant industrial waste has resulted in escalating environmental issue. Steel slag is the by-product of steel-making and can be used as cementitious materials in construction. However, the low activity of steel slag limits its utilization. Much investigation has been conducted on steel slag, while only a fraction of the investigation focuses on the effect of steel slag particle size on the properties of mortar. The aim of this study is to investigate the effect of steel slag particle size as cement replacement on properties of steel slag mortar activated by sodium sulphate (Na2SO4º. In this study, two types of steel slag, classified as fine steel slag (FSS) with particle sizes of 0.075mm and coarse steel slag (CSS) with particle sizes of 0.150 mm, were used for making alkali activated steel slag (AASS) mortar. Flow table test, compressive strength test, flexural strength test and UPV test were carried out by designing and producing AASS mortar cubes of (50 x 50 x 50) mm at 0, 10%, 20% and 30% replacement ratio and at 0.85% addition of Na2SO4. The results show that the AASS mortar with FSS possess a relatively good strength in AASS mortar. AASS mortar with FSS which is relatively finer shows a higher compressive strength than CSS up to 38.0% with replacement ratio from 10% to 30%. This study provided the further investigation on the combined influence of replacement ratio and particle size of SS in the properties of fresh and hardened AASS.