Alida Abdullah
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Alida Abdullah
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Alida, Abdullah
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Abdullah, Alida
Abdullah, A.
Abdullah, A. C.
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54979598300

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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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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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Fly ash based geopolymer as lightweight aggregate with low processing temperature for structural insulating concrete application.

2019 , Alida Abdullah

The lightweight aggregate in concrete has been broadly used nowadays due to its low density with great mechanical properties. These lightweight aggregates can be produced by thermal treatment from either naturally resource or from industrial by-product. However, the current production methods usually involving high energy due to high sintering temperature used despite of giving a great mechanical properties. Hence, there is a clear need of searching and replacing for more competent and proficient methods beyond the limitations of the current methods. Geopolymer becomes an attractive research due to its improving concrete properties and preserves the environment by using industrial waste such as fly ash. This research focuses on producing a fly ash geopolymer lightweight aggregate with good thermal insulation properties for structural concrete application with minimal sintering temperature by using geopolymerization methods. The 1effects of geopolymeric synthesis parameters such as the NaOH concentration (6 M, 8 M, 10 M, 12 M and 14 M), ratio of fly ash/alkali activator (2.0, 2.5, 3.0 and 3.5), and sintering temperature (400 °C to 1200 °C) to the fly ash geopolymer lightweight aggregate on mechanical and microstructure properties were studied. The optimum aggregate properties in term of highest impact strength with low density and water absorption then tested its thermal insulation properties through the effects of thermal conductivity, thermal diffusivity and specific heat capacity of aggregates. The results indicated that the fly ash geopolymer aggregate have an optimum NaOH concentration of 12 M with AIV of 22.43 % and an optimum ratio fly ash/alkali activator of 3.0 with AIV of 21.43 %. For the effect of sintering temperature, the results showed aggregate with sintering temperature of 900 °C gives the lowest AIV value (14.77 %) indicating highest impact strength with lightweight density (1730 kg/m3) and lowest water absorption (4.50 %). For thermal properties, at the aggregate of 900 °C shows the lowest thermal conductivity and diffusivity of 0.585 W/mK and 0.358 mm2/s, respectively. The performance of fly ash geopolymer lightweight aggregate in OPC concrete were tested for its mechanical and thermal properties and compared with the concrete of commercial lightweight aggregate. The results of concrete with fly ash geopolymer lightweight aggregate has shown better properties in term of strength with 43.71 MPa of compressive strength at 28 days, water absorption of 8.36 % and density of 1735 kg/m3 which can be classified as structural lightweight aggregate concrete according to ACI 213R. Concrete with fly ash geopolymer lightweight aggregate presented good thermal insulation properties through thermal conductivity results as low as 0.28 W/mK which makes it suitable for use as a good thermal insulation material. This work expands the findings contribution of microspheres in fly ash and the effect of iron (Fe) content to the geopolymerization process as well as produces a geopolymer lightweight aggregate with good thermal properties and high impact strength at low processing temperature.

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Geopolymer coating paste on concrete for photocatalytic performance

2021-05-03 , Liyana Jamaludin , Rafiza Abd Razak , Mohd. Mustafa Al Bakri Abdullah , Kusbiantoro A. , Zarina Yahya , Alida Abdullah , Sandu A.V.

Construction materials mainly used Portland cement as raw materials mainly caused global warming effect around the world. This article report a review on a research work carried out on the use of geopolymer coating on the concrete surface with catalyst for a good adsorption and efficiency via photocatalytic activity using sunlight. The geopolymer paste deposited by coating on the concrete or other building construction surface. The geopolymer paste were prepared by mixing aluminosilicates material with alkaline activator added with catalyst materials such as titanium dioxide and zinc oxide. The performance of geopolymer coating in removal of dyes reported comparable with other materials. Photocatalytic activity performance evaluate by adsorption of dyes onto geopolymer.

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Development of composite cement reinforced with coconut fibre

2012 , Alida Abdullah

This research was conducted to develop cement composite with the addition of coconut fibre in cement panel. The raw materials used were Ordinary Portland cement, coconut fibre, sand and water. The development of cement composites in this research were done by substituting coconut fibre to the portion of sand based on the ratio of cement to sand. In this study, the ratios used to design the mixture were 1:1:0, 1:0.97:0.03, 1:0.94:0.06, 1:0.91:0.09, 1:0.87:0.12 and 1:0.84:0.15 (cement: sand: coconut fibre). The amount of water per cement ratio was fixed at 0.55 for each mixture ratio. The sizes of sample tested were, 160 mm x 40 mm x 40 mm for compression test, and 100 mm x 100 mm x 40 mm for density, moisture content and water absorption tests. The samples were cured in water for 7, 14, and 28 days. The result shows that the cement composite with 9 wt. % of coconut fibre gives highest flexural and compressive strength. It was found that by increasing the content of coconut fibre, the density of cement composite was decreased while the water absorption and the moisture content percentages were increased. This study also reports the fracture behaviour of composites after flexural test. It revealed the crack bridging had strengthened the composite.

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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.

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The effects of various concentrations of NaOH on the Inter-Particle Gelation of a Fly Ash Geopolymer Aggregate

2021 , Alida Abdullah , Kamarudin Hussin , Mohd. Mustafa Al Bakri Abdullah , Zarina Yahya , Wojciech Sochacki , Rafiza Abdul Razak , Katarzyna Błoch , Hamzah Fansuri

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.

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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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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.

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The Effects of Various Concentrations of NaOH on the Inter-Particle Gelation of a Fly Ash Geopolymer Aggregate

2021 , Alida Abdullah , Kamarudin Hussin , Mohd. Mustafa Al Bakri Abdullah , Zarina Yahya , Wojciech Sochacki , Katarzyna Błoch , Hamzah Fansuri , Rafiza Abdul Razak

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.

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