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1

Thermal Insulation and Mechanical Properties in the Presence of Glas Bubble in Fly Ash Geopolymer Paste

Shahedan Noor Fifinatasha, Al Bakri Abdullah Mohd Mustafa, Mahmed Norsuria, Ming Liew Yun, Abd Rahim Shayfull Zamree, Aziz Ikmal Hakem A., Kadir Aeslina Abdul, Sandu Andrei Victor, Ghazali Mohd Fathullah

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 1

221--226

EN

The density, compressive strength, and thermal insulation properties of fly ash geopolymer paste are reported. Novel insulation material of glass bubble was used as a replacement of fly ash binder to significantly enhance the mechanical and thermal properties compared to the geopolymer paste. The results showed that the density and compressive strength of 50% glass bubble was 1.45 g/cm3 and 42.5 MPa, respectively, meeting the standard requirement for structural concrete. Meanwhile, the compatibility of 50% glass bubbles tested showed that the thermal conductivity (0.898 W/mK), specific heat (2.141 MJ/m3 K), and thermal diffusivity (0.572 mm2 /s) in meeting the same requirement. The improvement of thermal insulation properties revealed the potential use of glass bubbles as an insulation material in construction material.

2

The Investigation of Ground Granulated Blast Furnace Slag Geopolymer at High Temperature by Using Electron Backscatter Diffraction Analysis

Aziz Ikmal Hakem, Al Bakri Abdullah Mohd Mustafa, Salleh Mohd Arif Anuar Mohd, Yoriya Sorachon, Razak Rafiza Abd, Mohamed Rosnita, Baltatu Madalina Simona

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 1

227--231

EN

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.

3

Silica Bonding Reaction on Fly Ash Based Geopolymer Repair Material System with Incorporation of Various Concrete Substrates

Al Bakri Abdullah Mohd Mustafa, Aziz Ikmal Hakem A., Zailani Warid Wazien Ahmad, Rahim Shayfull Zamree Abd, Yong Heah Cheng, Sandu Andrei Victor, Peng Loke Siu

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 4

1277--1281

EN

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.

4

Setting Time and after Setting Properties of High Calcium Fly Ash Geopolymers with Different Concentration of Sodium Hydroxide

Mohamed Rosnita, Abd Razak Rafiza, Al Bakri Abdullah Mohd Mustafa, Sofri Liyana Ahmad, Aziz Ikmal Hakem, Shahedan Noor Fifinatasha

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 2

563--567

EN

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.

5

Review on Mechanical Properties of Metakaolin Geopolymer Concrete by Inclusion of Steel Fibers

Faris Meor Ahmad, Al Bakri Abdullah Mohd Mustafa, Muniandy Ratnasamy, Ramasamy Shamala, Abu Hashim Mohammad Firdaus, Junaedi Subaer, Sandu Andrei Victor, Tahir Muhammad Faheem Mohd

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 1

261--267

EN

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.

6

Recycling of PET Bottles Into Different Types of Building Materials: A Review

Hassan Mohd Ikhmal Haqeem, Kadir Aeslina Abdul, Arzlan Intan Seri Izzora, Tomari Mohd Razali Md, Mardi Noor Azizi, Hassan Mohd Fahrul, Al Bakri Abdullah Mohd Mustafa, Nabiałek Marcin, Jeż Bartłomiej

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 1

189--196

EN

In this globalized era, building materials play an essential role in the civil engineering field. Nowadays, with the increase in population, the demand for construction activities is also increasing. Polyethylene (PET) bottles are among the most widely used materials and cause an abundance of non-degradable waste, at about 0.94 million tonnes in Malaysia. One of the alternatives to reduce this waste's environmental impact is to incorporate it inside building materials such as brick and concrete. As PET bottles' recycling is highly promoted, the physical and mechanical properties of building materials made from PET bottles have also been reviewed. The data analysis shows that the compressive strength, flexural strength, split tensile strength and density of building materials decreases as the percentage of PET waste increases. However, other properties such as water absorption, initial absorption rate, and firing shrinkage increase proportionally with the PET waste. Besides, heavy metals in these building materials comply with the United States Environmental Protection Agency (USEPA) standards. It can be concluded that the percentage of PET waste incorporated into brick and concrete must be less than 5% and 2%, respectively, to produce suitable materials to provide alternatives in reducing and recycling PET waste.

7

Phase Analysis of Different Liquid Ratio on Metakaolin/Dolomite Geopolymer

Sauffi Ahmad Syauqi, Ibrahim Wan Mastura Wan, Al Bakri Abdullah Mohd Mustafa, Ibrahim Masdiyana, Ahmad Romisuhani, Zaidi Fakhryna Ahmad

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 1

247--250

EN

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.

8

Optimization of Injection Moulding Process via Design of Experiment (DOE) Method based on Rice Husk (RH) Reinforced Low Density Polyethylene (LDPE) Composite Properties

Jaya Haliza, Zulkepli Nik Noriman, Omar Mohd Firdaus, Abd Rahim Shayfull Zamree, Nabiałek Marcin, Jeż Kinga, Al Bakri Abdullah Mohd Mustafa

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 2

719--727

EN

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.

9

Mechanical Properties and Toxicity Characteristic of Petroleum Sludge Incorporated with Palm Oil Fuel Ash and Quarry Dust in Solidification/Stabilization Matrices

Hassan Mohd Ikhmal Haqeem, Kadir Aeslina Abdul, Kamil Nor Amani Filzah Mohd, Hashar Nurul Nabila Huda, Sarani Noor Amira, Ibrahim Badaruddin, Salleh Kahirol Mohd, Al Bakri Abdullah Mohd Mustafa

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 4

1259--1266

EN

This paper discussed the treatment of Malaysian petroleum sludge by incorporating palm oil fuel ash (POFA) to replace Portland cement and quarry dust (QD) replaces sand in the solidification/stabilization (S/S) method. Preliminary studies, including chemical composition, heavy metal characterization, density test, compressive strength test, and toxicity characteristic leaching procedure (TCLP), were done to evaluate POFA and QD suitability in S/S matrices. The 10% replacement of POFA recorded a considerable density value ranging from 1500 kg/m3 to 1660 kg/m3. As for S/S matrices containing petroleum sludge, the results indicate the possibility to of encapsulating the sludge in the matrices up to 10%. The highest strength of S/S matrices with petroleum is from PS5% samples with 15.61 MPa at 28 days. The toxicity characteristic of heavy metals from the S/S matrices was below the permissible limit set by USEPA. This investigation could be an alternative solution for petroleum sludge, POFA, and QD disposal and has excellent potential for replacing other treatment approaches employed at the advanced treatment stage for petroleum refinery effluents.

10

Mechanical Effects on Different Solid to Liquid Ratio of Geopolymer Filler in Epoxy Resin

Abu Hashim Mohammad Firdaus, Ghazali Che Mohd Ruzaidi, Daud Yusrina Mat, Faris Meor Ahmad, Al Bakri Abdullah Mohd Mustafa, Zainal Farah Farhana, Hasyim Saloma, Lokman Muhammad Taqiyuddin

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 1

215--220

EN

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.

11

Mechanical and Dielectric Properties of Hybrid Carbon Nanotubes-Woven Glass Fibre Reinforced Epoxy Laminated Composites via the Electrospray Deposition Method

Zakaria Muhammad Razlan, Khairuddin Nur Aishahatul Syafiqa Mohammad, Omar Mohd Firdaus, Akil Hazizan Md, Othman Muhammad Bisyrul Hafi, Al Bakri Abdullah Mohd Mustafa, Abd Rahim Shayfull Zamree, Ting Sam Sung, Azmi Azida

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 2

669--675

EN

Herein, the effects of multi-walled carbon nanotubes (CNTs) on the mechanical and dielectric performance of hybrid carbon nanotube-woven glass fiber (GF) reinforced epoxy laminated composited are investigated. CNTs are deposited on woven GF surface using an electrospray deposition method which is rarely reported in the past. The woven GF deposited with CNT and without deposited with CNT are used to produce epoxy laminated composites using a vacuum assisted resin transfer moulding. The tensile, flexural, dielectric constant and dielectric loss properties of the epoxy laminated composites were then characterized. The results confirm that the mechanical and dielectric properties of the woven glass fiber reinforced epoxy laminated composited increases with the addition of CNTs. Field emission scanning electron microscope is used to examine the post damage analysis for all tested specimens. Based on this finding, it can be prominently identified some new and significant information of interest to researchers and industrialists working on GF based products.

12

Influence of Filler Surface Modification on Static and Dynamic Mechanical Responses of Rice Husk Reinforced Linear Low-Density Polyethylene Composites

Omar Mohd Firdaus, Al Bakri Abdullah Mohd Mustafa, Ting Sam Sung, Jeż Bartłomiej, Nabiałek Marcin, Md Akil Hazizan, Zulkepli Nik Noriman, Abd Rahim Shayfull Zamree, Azmi Azida

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 2

507--519

EN

Filler surface modification has become an essential approach to improve the compatibility problem between natural fillers and polymer matrices. However, there is limited work that concerns on this particular effect under dynamic loading conditions. Therefore, in this study, both untreated and treated low linear density polyethylene/rice husk composites were tested under static (0.001 s-1, 0.01 s-1 and 0.1 s-1) and dynamic loading rates (650 s-1, 900 s-1 and 1100 s-1) using universal testing machine and split Hopkinson pressure bar equipment, respectively. Rice husk filler was modified using silane coupling agents at four different concentrations (1, 3, 5 and 7% weight percentage of silane) at room temperature. This surface modification was experimentally proven by Fourier transform infrared and Field emission scanning electron microscopy. Results show that strength properties, stiffness properties and yield behaviour of treated composites were higher than untreated composites. Among the treated composites, the 5% silane weight percentage composite shows the optimum mechanical properties. Besides, the rate of sensitivity of both untreated and treated composites also shows great dependency on strain rate sensitivity with increasing strain rate. On the other hand, the thermal activation volume shows contrary trend. For fracture surface analysis, the results show that the treated LLDPE/RH composites experienced less permanent deformation as compared to untreated LLDPE/RH composites. Besides, at dynamic loading, the fracture surface analysis of the treated composites showed good attachment between RH and LLDPE.

13

Hierarchical Carbon Fiber-Carbon Nanotubes by Using Electrospray Deposition Method with Preserved Tensile Properties

Zakaria Muhammad Razlan, Akil Hazizan Md, Omar Mohd Firdaus, Al Bakri Abdullah Mohd Mustafa, Rahim Shayfull Zamree Abd, Nabiałek Marcin, Wysłocki Jerzy J.

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 4

1299--1304

EN

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.

14

Flexural Properties of Thin Fly Ash Geopolymers at Elevated Temperature

Ng Yong-Sing, Liew Yun Ming, Heah Cheng Yong, Al Bakri Abdullah Mohd Mustafa, Ng Hui-Teng, Chan Lynette Wei Ling

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 3

1145--1150

EN

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 using 12M 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.

15

Finite Element Analysis on Structural Behaviour of Geopolymer Reinforced Concrete Beam using Johnson-Cook Damage in ABAQUS

Mortar Nurul Aida Mohd, Al Bakri Abdullah Mohd Mustafa, Hussin Kamarudin, Razak Rafiza Abdul, Hamat Sanusi, Hilmi Ahmad Humaizi, Shahedan Noorfifi Natasha, Li Long Yuan, Aziz Ikmal Hakem A.

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 4

1349--1354

EN

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.

16

Enhancement of Tensile Properties of Glass Fibre Epoxy Laminated Composites Reinforced with Carbon Nanotubes interlayer using Electrospray Deposition

Zakaria Muhammad Razlan, Omar Mohd Firdaus, Akil Hazizan Md, Othman Muhammad Bisyrul Hafi, Al Bakri Abdullah Mohd Mustafa

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 2

685--690

EN

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.

17

Effect of Solid-To-Liquids and Na2SiO3-To-NaOH Ratio on Metakaolin Membrane Geopolymers

Ibrahim Masdiyana, Wan Ibrahim Wan Mastura, Al Bakri Abdullah Mohd Mustafa, Sauffi Ahmad Syauqi, Vizureanu Petrica

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 2

695--702

EN

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.

18

Effect of Sodium Aluminate on the Fresh and Hardened Properties of Fly Ash-Based One-Part Geopolymer

Ooi Wan-En, Liew Yun Ming, Yong Heah Cheng, Ho Li-Nge, Al Bakri Abdullah Mohd Mustafa, Ong Shee-Ween, Sandu Andrei Victor

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 2

441--445

EN

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.

19

Effect of Silica Fume and Alumina Addition on the Mechanical and Microstructure of Fly Ash Geopolymer Concrete

Min Fong Sue, Yong Heah Cheng, Ming Liew Yun, Al Bakri Abdullah Mohd Mustafa, Razi Hasniyati Md, Low Foo Wah, Ng Hui-Teng, Ng Yong-Sing

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 1

197--202

EN

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.

20

Effect of NaOH Molar Concentration on Microstructure and Compressive Strength of Dolomite/Fly Ash-Based Geopolymers

Azimi Emy Aizat, Mohd Salleh M. A. A., Al Bakri Abdullah Mohd Mustafa, Aziz Ikmal Hakem A., Hussin Kamarudin, Chaiprapa Jitrin, Vizureanu Petrica, Yoriya Sorachon, Nabiałek Marcin, Wyslocki Jerzy J.

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 3

993--998

EN

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.