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.
Main Affiliation
Scopus Author ID
51161919900
Researcher ID
AAL-1501-2020

Research Output
Now showing 1 - 5 of 5
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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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Solidification/Stabilization technology for radioactive wastes using cement: An appraisal

2023 , Ismail Luhar , Salmabanu Luhar , Mohd. Mustafa Al Bakri Abdullah , Andrei Victor Sandu , Petrica Vizureanu , Dumitru Doru Burduhos-Nergis , Rafiza Abd Razak , Thanongsak Imjai

Across the world, any activity associated with the nuclear fuel cycle such as nuclear facility operation and decommissioning that produces radioactive materials generates ultramodern civilian radioactive waste, which is quite hazardous to human health and the ecosystem. Therefore, the development of effectual and commanding management is the need of the hour to make certain the sustainability of the nuclear industries. During the management process of waste, its immobilization is one of the key activities conducted with a view to producing a durable waste form which can perform with sustainability for longer time frames. The cementation of radioactive waste is a widespread move towards its encapsulation, solidification, and finally disposal. Conventionally, Portland cement (PC) is expansively employed as an encapsulant material for storage, transportation and, more significantly, as a radiation safeguard to vigorous several radioactive waste streams. Cement solidification/stabilization (S/S) is the most widely employed treatment technique for radioactive wastes due to its superb structural strength and shielding effects. On the other hand, the eye-catching pros of cement such as the higher mechanical strength of the resulting solidified waste form, trouble-free operation and cost-effectiveness have attracted researchers to employ it most commonly for the immobilization of radionuclides. In the interest to boost the solidified waste performances, such as their mechanical properties, durability, and reduction in the leaching of radionuclides, vast attempts have been made in the past to enhance the cementation technology. Additionally, special types of cement were developed based on Portland cement to solidify these perilous radioactive wastes. The present paper reviews not only the solidification/stabilization technology of radioactive wastes using cement but also addresses the challenges that stand in the path of the design of durable cementitious waste forms for these problematical functioning wastes. In addition, the manuscript presents a review of modern cement technologies for the S/S of radioactive waste, taking into consideration the engineering attributes and chemistry of pure cement, cement incorporated with SCM, calcium sulpho–aluminate-based cement, magnesium-based cement, along with their applications in the S/S of hazardous radioactive wastes.

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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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Metakaolin/sludge based geopolymer adsorbent on high removal efficiency of Cu2+

2022 , Pilomeena Arokiasamy , Mohd. Mustafa Al Bakri Abdullah , Shayfull Zamree Abd. Rahim , Mohd Remy Rozainy Mohd Arif Zainol , Mohd Arif Anuar Mohd Salleh , Marwan Kheimi , Jitrin Chaiprapa , Andrei Victor Sandu , Petrica Vizureanu , Rafiza Abd Razak , Noorina Hidayu Jamil

Activated carbon (AC) has received a lot of interest from researchers for the removal of heavy metals from wastewater due to its abundant porous structure. However, it was found unable to meet the required adsorption capacity due to its amorphous structure which restricts the fundamental studies and structural optimization for improved removal performance. In addition, AC is not applicable in large scale wastewater treatment due its expensive synthesis and difficulty in regeneration. Thus, the researchers are paying more attention in synthesis of low cost geopolymer based adsorbent for heavy metal removal due its excellent immobilization effect. However, limited studies have focused on the synthesis of geopolymer based adsorbent for heavy metal adsorption by utilizing industrial sludge. Thus, the aim of this research was to develop metakaolin (MK) based geopolymer adsorbent with incorporation of two types of industrial sludge (S1 and S3) that could be employed as an adsorbent for removing copper (Cu2+) from aqueous solution through the adsorption process. The effects of varied solid to liquid ratio (S/L) on the synthesis of metakaolin/sludge based geopolymer adsorbent and the removal efficiency of Cu2+ by the synthesis adsorbent were studied. The raw materials and synthesized geopolymer were characterized by using x-ray fluorescence (XRF), x-ray diffraction (XRD), scanning electron microscope (SEM), fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) and micro XRF. The concentration of Cu2+ before and after adsorption was determined by atomic absorption spectroscopy (AAS) and the removal efficiency was calculated. The experimental data indicated that the synthesized geopolymer at low S/L ratio has achieved the highest removal efficiency of Cu2+ about 99.62 % and 99.37 % at 25 %:75 % of MK/S1 and 25 %:75 % of MK/S3 respectively compared to pure MK based geopolymer with 98.56 %. The best S/

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Study on polypropylene twisted bundle fiber reinforced lightweight foamed concrete

2023 , Md Azree Othuman Mydin , Mohd. Mustafa Al Bakri Abdullah , Rafiza Abd Razak , Mohd Nasrun Mohd Nawi , Puput Risdanareni , Poppy Puspitasari , Andrei Victor Sandu , Madalina Simona Baltatu , Petrica Vizureanu

Recent industrial developments have focused more and more on the applications of lightweight foamed concrete (LFC) in the construction industry, having advantages over normal-strength concrete. LFC, however, has several drawbacks including brittleness, high porosity, excessive drying shrinkage, rapid cracking, and low deformation resistance. Practical engineering typically chooses steel fiber or polymer fiber to increase the tensile and fracture resistance of LFC. The polypropylene twisted bundle fiber (PTBF) was added to the LFC with varying weight fractions of 0.0%, 0.5%, 1.0%, 1.5%, 2.0% and 2.5%. Three low densities of LFC were prepared, specifically 500 kg/m3, 700 kg/m3 and 900 kg/m3. The mechanical and durability properties of PTBF-reinforced LFC were determined through compression, flexural, splitting tensile, flow table, porosity, and water absorption tests. The results show that the addition of PTBF in LFC significantly improves the strength properties (compressive, flexural, and splitting tensile strengths) and reduces the water absorption capacity and porosity. The optimal weight fraction of PTBF was between 1.5 and 2.0% for mechanical properties enhancement. The inclusion of PTBF increased the ductility of LFC, and the specimens remain intact from loading to failure. The PTBF reduces the original cracks of the LFC and inhibits the development of further cracks in the LFC.

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