Zarina Yahya
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Zarina Yahya
Official Name
Zarina, Yahya
Alternative Name
Yahya, Zarina
Zarina, Y.
Zarina, Yahya
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Scopus Author ID
51162069600
Researcher ID
DXZ-6436-2022

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  • Publication
    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.
  • Publication
    Rice husk (RH) as additive in fly ash based geopolymer mortar
    ( 2017-09-26)
    Zarina Yahya
    ;
    Rafiza Abd Razak
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Mohd Azrin Adzhar Rahim
    ;
    Armia Nasri
    In recent year, the Ordinary Portland Cement (OPC) concrete is vastly used as main binder in construction industry which lead to depletion of natural resources in order to manufacture large amount of OPC. Nevertheless, with the introduction of geopolymer as an alternative binder which is more environmental friendly due to less emission of carbon dioxide (CO2) and utilized waste materials can overcome the problems. Rice husk (RH) is an agricultural residue which can be found easily in large quantity due to production of paddy in Malaysia and it's usually disposed in landfill. This paper investigated the effect of rice husk (RH) content on the strength development of fly ash based geopolymer mortar. The fly ash is replaced with RH by 0%, 5%, 10%, 15% and 20% where the sodium silicate and sodium hydroxide was used as alkaline activator. A total of 45 cubes were casted and their compressive strength, density and water absorption were evaluated at 1, 3, and 7 days. The result showed compressive strength decreased when the percentage of RH increased. At 5% replacement of RH, the maximum strength of 17.1MPa was recorded at day 7. The geopolymer has lowest rate of water absorption (1.69%) at 20% replacement of RH. The density of the sample can be classified as lightweight geopolymer concrete.
  • Publication
    The effect Na2SiO3/NaOH ratio to specific gravity and water absorption of artifiticial geopolymer aggregate dolomite based
    ( 2017-09-26)
    Aiman Mahmad Nor
    ;
    Zarina Yahya
    ;
    Mohd. Mustafa Al Bakri Abdullah
    Industry such as construction and materials had depended a lot on the available aggregate. The use of aggregate need to be designed so that it have a well sustainable system with good physical properties. This paper is using dolomite to produce an artificial aggregate. The dolomite based artificial aggregate is produced using geopolymer as a hardened process. The dolomite base artificial aggregate is tested with a different alkaline activator to find water absorption and density. The lowest water absorption of dolomite artificial aggregate is 14%. The specific gravity of the artificial aggregate tested are lower when the sodium silicate is decreasing. The lowest density of artificial aggregate obtain are with 2.03 g/cm3.
  • Publication
    Properties of Blended Alkaline System Geopolymer-A Review
    ( 2020-03-18)
    Ahmad Zaidi F.H.
    ;
    Romisuhani Ahmad
    ;
    Zarina Yahya
    ;
    Muhammad Faheem Mohd. Tahir
    ;
    Wan Mastura Wan Ibrahim
    ;
    Saufi A.S.
    Geopolymers are inorganic material that comprise of silicon(Si) and aluminium(Al) bonded by oxygen atom to form a polymer network. The binder material used for geopolymer such as fly ash and blast furnace are mostly the industrial waste or by-products containing high content of silica and aluminium which acted as precursor for geopolymerization. The raw material plays an important role in the formation of geopolymer for each material may result in different properties of geopolymer. To improve the performance of these binders, numerous studies have been focused on the production of mixes based on blends of reactive precursors. The blends usually involve a Ca-rich precursor such as granulated blast furnace slag (GGBS), and an aluminosilicate source such as metakaolin or low calcium fly ash, to promote the stable coexistence of calcium silicate hydrate (C-S-H) gels formed from the activation of the GGBS and the geopolymer gel (N-A-S-H) produced from the activation of the aluminosilicate. Thus, this paper is intended to review the properties of different type of mixes of blended alkaline system.
  • Publication
    Performance of Sintered Pozzolanic Artificial Aggregates as Coarse Aggregate Replacement in Concrete
    ( 2021-01-01)
    Rafiza Abd Razak
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Kamarudin Hussin
    ;
    Subaer
    ;
    Zarina Yahya
    ;
    Mohamed R.
    ;
    Alida Abdullah
    The abundant increase in waste quantities year by year and the depletion of natural resources worldwide are the major concerns among researchers. Recycling and reusing various types of natural or by-product material waste from industry become highlighted in the recent study. The growing demand for concrete and the production of artificial aggregate become crucial in the construction industry. Artificial aggregate can be produced either by sintering, auto-clave or cold bonding method. Although auto-clave and cold bonding methods can minimize energy consumption, the selection of the sintering method always leads to high quality and better properties of artificial aggregates produced. The use of sintering methods to produce artificial aggregate made from pozzolanic material focuses on the use of volcanic ash as raw material activated by geopolymerization process to produce artificial lightweight aggregate-based geopolymer will be summarized in this chapter. This chapter discusses the result of the physical and mechanical properties of artificial lightweight aggregate or known as sintered geopolymer volcanic ash artificial lightweight aggregate (SGVA). The interfacial transition zone (ITZ) of sintered geopolymer volcanic ash artificial lightweight aggregate (SGVA) is presented. The performance of sintered geopolymer volcanic ash artificial lightweight aggregate (SGVA) in concrete is also discussed.
      1
  • Publication
    The Effect of NaOH Concentration on Palm Oil Boiler Ash (POBA) based Geopolymer Artificial Aggregate
    ( 2024-04-19)
    Hao D.L.C.
    ;
    Rafiza Abd Razak
    ;
    Zarina Yahya
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Subaer
    Industrial wastes or by-products can be used to create artificial aggregates. Solid waste created by the palm oil industry is a significant environmental problem that requires immediate and long-term solutions. The optimal ratio of geopolymer-based palm oil boiler ash (POBA) aggregate in terms of specific gravity, water absorption, and aggregate impact value was explored in this work. Because of its high percentages of silica oxide (SiO2) and aluminium oxide (Al2O3), POBA was chosen as the primary precursor for the geopolymer (Al2O3). The POBA aggregate with the lowest specific gravity was 1.662, while all of the geopolymer-based POBA aggregates had specific gravities below 2. The geopolymer-based POBA aggregate absorbs more water than the natural aggregate. The aggregate effect value for sodium hydroxide concentrations (6M, 8M, 10M, 12M, 14M) is less than 30%, which is considered strong.
      1
  • Publication
    Behavior of alkali-activated fly ash through underwater placement
    ( 2021-11-01)
    Zarina Yahya
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Li Long-Yuan
    ;
    Nergis D.D.B.
    ;
    Muhammad Aiman Asyraf Zainal Hakimi
    ;
    Sandu A.V.
    ;
    Vizureanu P.
    ;
    Rafiza Abd Razak
    Underwater concrete is a cohesive self-consolidated concrete used for concreting underwater structures such as bridge piers. Conventional concrete used anti-washout admixture (AWA) to form a high-viscosity underwater concrete to minimise the dispersion of concrete material into the surrounding water. The reduction of quality for conventional concrete is mainly due to the washing out of cement and fine particles upon casting in the water. This research focused on the detailed investigations into the setting time, washout effect, compressive strength, and chemical composition analysis of alkali-activated fly ash (AAFA) paste through underwater placement in seawater and freshwater. Class C fly ash as source materials, sodium silicate, and sodium hydroxide solution as alkaline activator were used for this study. Specimens produced through underwater placement in seawater showed impressive performance with strength 71.10 MPa on 28 days. According to the Standard of the Japan Society of Civil Engineers (JSCE), the strength of specimens for underwater placement must not be lower than 80% of the specimen’s strength prepared in dry conditions. As result, the AAFA specimens only showed 12.11% reduction in strength compared to the specimen prepared in dry conditions, thus proving that AAFA paste has high potential to be applied in seawater and freshwater applications.
      2
  • Publication
    Surface resistivity and ultrasonic pulse velocity evaluation of reinforced opc concrete and reinforced geopolymer concrete in marine environment
    ( 2021-01-01)
    Mohd Badrul Hisyam Ab Manaf
    ;
    Zarina Yahya
    ;
    Rafiza Abd Razak
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Ariffin N.F.
    ;
    Muhammad Munsif Ahmad
    ;
    Chong Y.C.
    The concrete structures that are built along the seaside often suffer from reduced service life due to inadequate durability against deterioration. This research reports the findings of concrete resistivity and quality using two Non-Destructive Testing (NDT) measures applied to Reinforced Geopolymer and Ordinary Portland Cement (OPC) concrete in the marine environment. In addition, the relationship between Reinforced Geopolymer and Reinforced OPC concrete was statistically discussed in-terms of strength and direction. The testing was carried out using a Proceeq Resipod Wenner 4-probe to measure Surface Resistivity (SR) and Ultrasonic Pulse Velocity (UPV), respectively. The testings were carried out on beam shaped samples of OPC and Geopolymer concrete that were immersed in seawater over a period of 90 days with similar curing condition. It was found from the present investigation that the maximum SR and maximum UPV values acquired for both the Reinforced OPC and Reinforced Geopolymer concrete are 2.73 kΩcm and 2.07 kΩcm, as well as 4.18 km/s and 4.05 km/s, respectively. It is apparent from the study that both concrete is comparable in terms of quality and surface resistivity.
      1
  • Publication
    Article the effects of various concentrations of naoh on the inter-particle gelation of a fly ash geopolymer aggregate
    ( 2021-03-01)
    Alida Abdullah
    ;
    Kamarudin Hussin
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Zarina Yahya
    ;
    Sochacki W.
    ;
    Rafiza Abd Razak
    ;
    Błoch K.
    ;
    Fansuri H.
    Aggregates can be categorized into natural and artificial aggregates. Preserving natural resources is crucial to ensuring the constant supply of natural aggregates. In order to preserve these natural resources, the production of artificial aggregates is beginning to gain the attention of researchers worldwide. One of the methods involves using geopolymer technology. On this basis, this current research focuses on the inter-particle effect on the properties of fly ash geopolymer aggregates with different molarities of sodium hydroxide (NaOH). The effects of synthesis parameters (6, 8, 10, 12, and 14 M) on the mechanical and microstructural properties of the fly ash geopolymer aggregate were studied. The fly ash geopolymer aggregate was palletized manually by using a hand to form a sphere-shaped aggregate where the ratio of NaOH/Na2SiO3 used was constant at 2.5. The results indicated that the NaOH molarity has a significant effect on the impact strength of a fly ash geopolymer aggregate. The highest aggregate impact value (AIV) was obtained for samples with 6 M NaOH molarity (26.95%), indicating the lowest strength among other molarities studied and the lowest density of 2150 kg/m3 . The low concentration of sodium hydroxide in the alkali activator solution resulted in the dissolution of fly ash being limited; thus, the inter-particle volume cannot be fully filled by the precipitated gels.
      1
  • Publication
    Effect of Rice Straw Ash (RSA) as partially replacement of cement toward fire resistance of self-compacting concrete
    ( 2022-01-01)
    Rafiza Abd Razak
    ;
    Chin Y.Q.
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Zarina Yahya
    ;
    Mokhzani Khair Ishak
    ;
    Garus S.
    ;
    Nabiałek M.
    ;
    Zailani W.W.A.
    ;
    Masri K.A.
    ;
    Sandu A.V.
    ;
    Śliwa A.
    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.
      5