Rafiza Abd Razak
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Preferred name
Rafiza Abd Razak
Official Name
Rafiza, Abd Razak
Alternative Name
Rafiza, Abd Razak
Rafiza, Abdul Razak
Abdul Razak, Rafiza
Rafiza, R. A.
Razak, Rafiza Abd
Rafiza, A. R.
Abdul Razak, R.
Razak, R. A.
Razak, Rafiza Abdul
Razak, A. R.
Abd Razak, R.
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Scopus Author ID
51161919900
Researcher ID
AAL-1501-2020

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The effect of various waste materials' contents on the attenuation level of anti-radiation shielding concrete

2013 , Ali Azeez , Kahtan Mohammed , Mohd. Mustafa Al Bakri Abdullah , Kamarudin Hussin , Sandu, Andrei Victor , Rafiza Abd Razak

Samples of concrete contain various waste materials, such as iron particulates, steel balls of used ball bearings and slags from steel industry were assessed for their anti-radiation attenuation coefficient properties. The attenuation measurements were performed using gamma spectrometer of NaI (Tl) detector. The utilized radiation sources comprised 137Cs and 60Co radioactive elements with photon energies of 0.662 MeV for 137Cs and two energy levels of 1.17 and 1.33 MeV for the 60Co. Likewise the mean free paths for the tested samples were obtained. The aim of this work is to investigate the effect of the waste loading rates and the particulate dispersive manner within the concrete matrix on the attenuation coefficients. The maximum linear attenuation coefficient (μ) was attained for concrete incorporates iron filling wastes of 30 wt %. They were of 1.12 ± 1.31×10-3 for 137Cs and 0.92 ± 1.57 × 10-3 for 60Co. Substantial improvement in attenuation performance by 20%-25% was achieved for concrete samples incorporate iron fillings as opposed to that of steel ball samples at different (5%-30%) loading rates. The steel balls and the steel slags gave much inferior values. The microstructure, concrete-metal composite density, the homogeneity and particulate dispersion were examined and evaluated using different metallographic, microscopic and measurement facilities.

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Artificial lightweight aggregates made from pozzolanic material: A review on the method, physical and mechanical properties, thermal and microstructure

2022 , Dickson Ling Chuan Hao , Rafiza Abd Razak , Marwan Kheimi , Zarina Yahya , Mohd. Mustafa Al Bakri Abdullah , Dumitru Doru Burduhos Nergis , Hamzah Fansuri , Ratna Ediati , Rosnita Mohamed , Alida Abdullah

As the demand for nonrenewable natural resources, such as aggregate, is increasing worldwide, new production of artificial aggregate should be developed. Artificial lightweight aggregate can bring advantages to the construction field due to its lower density, thus reducing the dead load applied to the structural elements. In addition, application of artificial lightweight aggregate in lightweight concrete will produce lower thermal conductivity. However, the production of artificial lightweight aggregate is still limited. Production of artificial lightweight aggregate incorporating waste materials or pozzolanic materials is advantageous and beneficial in terms of being environmentally friendly, as well as lowering carbon dioxide emissions. Moreover, additives, such as geopolymer, have been introduced as one of the alternative construction materials that have been proven to have excellent properties. Thus, this paper will review the production of artificial lightweight aggregate through various methods, including sintering, cold bonding, and autoclaving. The significant properties of artificial lightweight aggregate, including physical and mechanical properties, such as water absorption, crushing strength, and impact value, are reviewed. The properties of concrete, including thermal properties, that utilized artificial lightweight aggregate were also briefly reviewed to highlight the advantages of artificial lightweight aggregate.

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Marshall stability of porous asphalt mixture incorporating kenaf fiber

2022 , Nur Ezreen Jasni , Khairi Azman Masri , Ramadhansyah Putra Jaya , Mohd. Mustafa Al Bakri Abdullah , Rafiza Abd Razak , Marcin Nabiałek , Katarzyna Błoch , Agata Śliwa

Porous asphalt mixture (PA), known as open-graded surfaces over a stone bed underneath, allows water to go through. These factors can affect the porous asphalt mixture adhesive strength. The high amount of course aggregate promotes the structure of air voids have certain impacts on the acoustic properties of porous asphalt. The materials properties are consisting of both aggregate and bitumen tests. This study also details out the aggregates sieve analysis test to develop new aggregate gradation for PA. According to five ASEAN countries’ specifications, the sieve analysis test was done. The countries included are Malaysia, Vietnam, Thailand, Singapore, and Indonesia. The test for the binder includes the softening point, penetration, and ductility. This study also investigates the addition of kenaf fiber in the mixture as an additive. Mechanical performance test for PA using Marshall Stability test to identify the strength and the properties of the conventional PA with the addition of kenaf fiber compared to the new gradation of PA incorporating kenaf fiber. From the results, the addition of 0.3% kenaf modified PA improved the performance of PA in terms of Marshall Stability and volumetric properties

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A State-of-the-Art Review on innovative geopolymer composites designed for water and wastewater treatment

2021 , Ismail Luhar , Salmabanu Luhar , Mohd. Mustafa Al Bakri Abdullah , Petrica Vizureanu , Rafiza Abd Razak , Andrei Victor Sandu , Petre-Daniel Matasaru

There is nothing more fundamental than clean potable water for living beings next to air. On the other hand, wastewater management is cropping up as a challenging task day-by-day due to lots of new additions of novel pollutants as well as the development of infrastructures and regulations that could not maintain its pace with the burgeoning escalation of populace and urbanizations. Therefore, momentous approaches must be sought-after to reclaim fresh water from wastewaters in order to address this great societal challenge. One of the routes is to clean wastewater through treatment processes using diverse adsorbents. However, most of them are unsustainable and quite costly e.g. activated carbon adsorbents, etc. Quite recently, innovative, sustainable, durable, affordable, user and eco-benevolent Geopolymer composites have been brought into play to serve the purpose as a pretty novel subject matter since they can be manufactured by a simple process of Geopolymerization at low temperature, lower energy with mitigated carbon footprints and marvellously, exhibit outstanding properties of physical and chemical stability, ion-exchange, dielectric characteristics, etc., with a porous structure and of course lucrative too because of the incorporation of wastes with them, which is in harmony with the goal to transit from linear to circular economy, i.e., “one’s waste is the treasure for another”. For these reasons, nowadays, this ground-breaking inorganic class of amorphous alumina-silicate materials are drawing the attention of the world researchers for designing them as adsorbents for water and wastewater treatment where the chemical nature and structure of the materials have a great impact on their adsorption competence. The aim of the current most recent state-of-the-art and scientometric review is to comprehend and assess thoroughly the advancements in geo-synthesis, properties and applications of geopolymer composites designed for the elimination of hazardous contaminants viz., heavy metal ions, dyes, etc. The adsorption mechanisms and effects of various environmental conditions on adsorption efficiency are also taken into account for review of the importance of Geopolymers as most recent adsorbents to get rid of the death-defying and toxic pollutants from wastewater with a view to obtaining reclaimed potable and sparkling water for reuse offering to trim down the massive crisis of scarcity of water promoting sustainable water and wastewater treatment for greener environments. The appraisal is made on the performance estimation of Geopolymers for water and wastewater treatment along with the three-dimensional printed components are characterized for mechanical, physical and chemical attributes, permeability and Ammonium (NH4+) ion removal competence of Geopolymer composites as alternative adsorbents for sequestration of an assortment of contaminants during wastewater treatment.

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Mechanical performance, microstructure, and porosity evolution of fly ash geopolymer after ten years of curing age

2023 , Ikmal Hakem A. Aziz , Mohd. Mustafa Al Bakri Abdullah , Rafiza Abd Razak , Zarina Yahya , Mohd Arif Anuar Mohd Salleh , Jitrin Chaiprapa , Catleya Rojviriya , Petrica Vizureanu , Andrei Victor Sandu , Muhammad Faheem Mohd. Tahir , Alida Abdullah , Liyana Jamaludin

This paper elucidates the mechanical performance, microstructure, and porosity evolution of fly ash geopolymer after 10 years of curing age. Given their wide range of applications, understanding the microstructure of geopolymers is critical for their long-term use. The outcome of fly ash geopolymer on mechanical performance and microstructural characteristics was compared between 28 days of curing (FA28D) and after 10 years of curing age (FA10Y) at similar mixing designs. The results of this work reveal that the FA10Y has a beneficial effect on strength development and denser microstructure compared to FA28D. The total porosity of FA10Y was also lower than FA28D due to the anorthite formation resulting in the compacted matrix. After 10 years of curing age, the 3D pore distribution showed a considerable decrease in the range of 5–30 µm with the formation of isolated and intergranular holes.

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Waste material via geopolymerization for heavy-duty application: a review

2022 , Marwan Kheimi , Ikmal Hakem Aziz , Mohd. Mustafa Al Bakri Abdullah , Mohammad Almadani , Rafiza Abd Razak

Due to the extraordinary properties for heavy-duty applications, there has been a great deal of interest in the utilization of waste material via geopolymerization technology. There are various advantages offered by this geopolymer-based material, such as excellent stability, exceptional impermeability, self-refluxing ability, resistant thermal energy from explosive detonation, and excellent mechanical performance. An overview of the work with the details of key factors affecting the heavy-duty performance of geopolymer-based material such as type of binder, alkali agent dosage, mixing design, and curing condition are reviewed in this paper. Interestingly, the review exhibited that different types of waste material containing a large number of chemical elements had an impact on mechanical performance in military, civil engineering, and road application. Finally, this work suggests some future research directions for the the remarkable of waste material through geopolymerization to be employed in heavy-duty application.

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Setting time and after setting properties of high calcium fly ash geopolymers with different concentration of sodium hydroxide

2021 , Rosnita Mohamed , Rafiza Abd Razak , Mohd. Mustafa Al Bakri Abdullah , Ikmal Hakem Aziz , Liyana Ahmad Sofri , Noor Fifinatasha Shahedan

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.

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Geopolymer-based artificial aggregates: a review on methods of producing, properties, and improving techniques

2022 , Mohammad Almadani , Rafiza Abd Razak , Mohd. Mustafa Al Bakri Abdullah , Rosnita Mohamed

The depletion of aggregate-related natural resources is the primary concern of all researchers globally. Recent studies emphasize the significance of recycling and reusing various types of natural or by-product material waste from industry as a result of the building industry’s rising demand for aggregate as the primary component in concrete production. It has been demonstrated that the geopolymer system has exceptional features, such as high strength, superior durability, and greater resistance to fire exposure, making it a viable alternative to ordinary Portland Cement (OPC) concrete. This study will examine the present method utilized to generate artificial aggregate-based geopolymers, including their physical and mechanical properties, as well as their characterization. The production process of geopolymer derived from synthetic aggregates will be highlighted. In conjunction with the bonding of aggregates and the cement matrix, the interfacial transition zone (ITZ) is highlighted in this work as an additional important property to be researched in the future. It will be discussed how to improve the properties of geopolymers based on artificial aggregates. It has been demonstrated that cold bonding provides superior qualities for artificial aggregate while conserving energy during production. The creation of ITZ has a significant impact on the bonding strength between artificial aggregates and the cement matrix. Additionally, improvement strategies demonstrate viable methods for enhancing the quality of manufactured aggregates. In addition, other recommendations are discussed in this study for future work.

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Properties and morphology of fly ash based Alkali Activated Material (AAM) paste under steam curing condition

2022 , Rafiza Abd Razak , Sh. Nur Syamimi Sy. Izman , Mohd. Mustafa Al Bakri Abdullah , Zarina Yahya , Alida Abdullah , Rosnita Mohamed

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.

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Effect of Rice Straw Ash (RSA) as partially replacement of cement toward fire resistance of self-compacting concrete

2022 , Yi Qin Chin , Rafiza Abd Razak , Mohd. Mustafa Al Bakri Abdullah , Zarina Yahya , Mokhzani Khair Ishak , Sebastian Garus , Marcin Nabiałek , Warid Wazien Ahmad Zailani , Khairil Azman Masri , Andrei Victor Sandu , Agata Śliwa

Malaysia’s construction industry is experiencing rapid growth, translating into increased demand for cement. However, cement production pollutes the air to the detriment of the climate via CO2 emission, making research into a cementitious replacement in concrete a necessity. This paper details an experimental study of self-compacting concrete (SCC) with partial replacement of cement by rice straw ash (RSA), which is expected to result in environmental preservation due to the green materials being used in cement production. The physicomechanical properties of the SCC with RSA replacement were determined via its compressive strength, water absorption, self-workability, and fire resistance (residual strength after exposure to high temperatures). The proportion of RSA replacement used were 0%, 5%, 10%, 15%, 20%, and 25%, and all passed the slump flow test, except the 20% and 25% samples. The SCC samples with 15% of RSA replacement reported the highest compressive strength at 7 and 28 curing days and the highest residual strength post-exposure to high temperatures. The lowest percentage of water absorption was reported by the 15% of RSA replacement, with a density of 2370 kg/m3

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