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
    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
  • Publication
    A Review on the Concrete Durability Exposed to Different Wet-Dry Cycles Conditions
    ( 2024-04-19)
    Zarina Yahya
    ;
    Rafiza Abd Razak
    ;
    Khairunnisa Muhamad
    Concrete structure is prone to corrosion and weathering when built near marine environment. The greater damage on the concrete can be observed when it involves wet-dry action such as tidal waves combine with the existence of aggressive ions such as sulphate and chloride in seawater. The objective of this study is to review on the mechanism of sulphate, chloride attack toward concrete, parameters that influence the wet-dry action and identify the overview of research trends. The mechanism of sulphate and chloride attack during wet-dry action had reciprocal inhibiting effect on concrete and the penetration level for each ion also vary. The physical and mechanical damage of concrete exposed to wet-dry action also influence by wet-dry ratio, number of cycles and temperature during drying process. The main compound detected during exposure period are Friedel salt, ettringite, mirabilite and thenardite which can cause concrete delamination and spalling.
  • Publication
    Development of High Strength Alluvial Brick by Incorporative of Coconut Fibre
    ( 2024-04-19)
    Rafiza Abd Razak
    ;
    Sagaran R.
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Zarina Yahya
    ;
    Junaidi S.
    ;
    Alida Abdullah
    The new properties of alluvial brick can be created by addition to the coconut fibre. An analysis on compressive strength and water absorption percentage of alluvial brick and coconut fibre alluvial brick are presented in this research. There are four main different operations are involved in the process of manufacturing of alluvial bricks such as preparation of alluvial clay and coconut fibre, moulding of bricks, pre-drying of bricks and burning of bricks at 500°C, 600°C and 700°C. The results showed that the alluvial soil brick (without coconut fibre) burnt at 600°C exhibits the highest compressive strength of 17.33MPa and water absorption rate is 5.56% after soaked 24 hours in water. By using 600°C as the optimum temperature, alluvial bricks incorporating of coconut fibre are burnt. The highest value of compressive strength of coconut fibre alluvial brick is 16.57MPa and the water absorption is 11.11%. The outcomes of this research proved that the pure alluvial soil brick which not mixed with any add mixtures can be used in the construction project and it can be considered as a new type of brick in construction material. The coconut fibre alluvial brick also has fulfil the requirements to contribute to sustainable development as coconut fibre alluvial brick is made use of waste coconut fibre that environmental friendly and at the same time, it could decreases the waste material disposal.
  • 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
    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
    Durability of geopolymer lightweight concrete infilled LECA in seawater exposure
    ( 2017-11-23)
    Rafiza Abd Razak
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Zarina Yahya
    ;
    Hamid M.
    This paper describes a development of lightweight concrete using lightweight expanded clay aggregate (LECA) in fly ash (FA) based geopolymer immersed in seawater. The objective of this research is to compare the performance of geopolymer concrete (GPC) with ordinary Portland cement (OPC) concrete infilled lightweight expanded clay aggregate (LECA) in seawater exposure. Geopolymer concrete is produced by using alkaline activator to activate the raw material, FA. The highest compressive strength of this study is 42.0 MPa at 28 days and 49.8 MPa at 60 days. The density for this concrete is in the range of 1580 kg/m3 to 1660 kg/m3. The result for water absorption is in the range of 6.82% to 14.72%. However, the test results of weight loss is in the range between 0.30% to 0.43%.
  • Publication
    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.
  • 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
    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
    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