Wan Mastura Wan Ibrahim
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Preferred name
Wan Mastura Wan Ibrahim
Official Name
Wan Mastura, Wan Ibrahim
Alternative Name
Mastura Wan Ibrahim, Wan
Ibrahim, W. M.H.W.
Ibrahim, Wan Mastura Wan
Main Affiliation
Scopus Author ID
56526451500
Researcher ID
AGI-2890-2022

Research Output
Now showing 1 - 3 of 3
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Assessment of geopolymer concrete for underwater concreting properties

2021 , Fakhryna Hannanee Ahmad Zaidi , Romisuhani Ahmad , Mohd. Mustafa Al Bakri Abdullah , Wan Mastura Wan Ibrahim , Ikmal Hakem Aziz , Subaer Junaidi , Salmabanu Luhar

For ages, concrete has been used to construct underwater structures. Concrete laying underwater is a very complex procedure important to the success or failure of underwater projects. This paper elucidates the influence of alkali activator ratios on geopolymers for underwater concreting; focusing on the geopolymer concrete synthesized from fly ash and kaolin activated using sodium hydroxide and sodium silicate solutions. The geopolymer mixtures were designed to incorporate multiple alkali activator ratios to evaluate their effects on the resulting geopolymers’ properties. The fresh concrete was molded into 50 mm cubes in seawater using the tremie method and tested for its engineering properties at 7 and 28 days (curing). The control geopolymer and underwater geopolymers’ mechanical properties, such as compressive strength, water absorption density, and setting time were also determined. The differences between the control geopolymer and underwater geopolymer were determined using phase analysis and functional group analysis. The results show that the geopolymer samples were optimally strengthened at a 2.5 alkali activator ratio, and the mechanical properties of the control geopolymer exceeded that of the underwater geopolymer. However, the underwater geopolymer was determined to be suitable for use as underwater concreting material as it retains 70% strength of the control geopolymer.

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Publication

Design, processing and properties of fly ash-based lightweight geopolymer using foaming agent for brick application

2018 , Wan Mastura Wan Ibrahim

Lightweight concrete reduces the overall self-weight of the structures resulting in the reduction of the foundation size, cost, and other specification. However, the conventional lightweight concrete production causes several environmental impacts and produce low mechanical properties, so there is a clear need of searching and replacing for more efficient and durable alternatives beyond the limitations of the conventional lightweight concrete. Geopolymer represents a great opportunity to ensure greater sustainability in the construction industry especially for the use of industrial waste such as fly ash. This research focuses on the preparation of fly ash-based lightweight geopolymer using superplasticizer as foaming agent. The superplasticizer (Polyoxyethylene alkyether sulfate) was prepared using pre-formed method by combination with water and air pressure. The effects of geopolymeric synthesis parameters such as the NaOH concentration (6 M, 8 M, 10 M, 12 M and 14 M), ratio of foaming agent to water (1/10, 1/20, 1/30 and 1/40) by volume, ratio of foam to geopolymer paste (0.5, 1.0, 1.5 and 2.0) by volume, curing temperature (40 °C, 60 °C, 80 °C and 100 °C) and curing time (6, 12, 24 and 48) hours on the lightweight geopolymer paste that affect the mechanical and microstructure properties were studied in detailed. The compressive strength, water absorption, density, were studied to determine the mechanical properties of lightweight geopolymer. The thermal insulation properties was investigated through the effects of thermal conductivity, thermal diffusivity, and specific heat of lightweight geopolymer at different ageing time (3, 7, 28, 60 and 90) days. The microstructure properties of lightweight geopolymer were tested by using Scanning Electron Microscope. The results indicated that the lightweight geopolymer have an optimum NaOH concentration of 12 M, with highest compressive strength of 15.2 MPa at 7 days, an optimum ratio of foaming agent to water (1/10) and ratio of foam to geopolymer paste (1.0) with highest strength of 16.6 MPa (7 days), optimum curing temperature (80 °C) and curing time (24 hours) showed the highest strength and lowest density of 15.6 MPa and 1400 kg/m3, respectively. The thermal conductivity and thermal diffusivity of lightweight geopolymer are substantially lower with value of 0.63 W/mK to 0.83 W/mk and 0.26 mm2/s to 0.35 mm2/s, respectively. A potential new lightweight construction material can be produced by using low cost of foaming agent and easy to process for addition to geopolymer paste. The fly ash-based lightweight geopolymer produced in this work exhibit compressive strength in accordance to the standard for masonry lightweight applications at considerably lower curing temperature (80 °C).

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Chemical distributions of different Sodium Hydroxide molarities on fly ash/dolomite-based geopolymer

2022 , Wan Mastura Wan Ibrahim , Mohd. Mustafa Al Bakri Abdullah , Romisuhani Ahmad , Andrei Victor Sandu , Petrica Vizureanu , Omrane Benjeddou , Afikah Rahim , Masdiyana Ibrahim , Ahmad Syauqi Sauffi

Geopolymers are an inorganic material in an alkaline environment that is synthesized with alumina–silica gel. The structure of geopolymers consists of an inorganic chain of material and a covalent-bound molecular system. Currently, Ordinary Portland Cement (OPC) has caused carbon dioxide (CO2) emissions which causes greenhouse effects. This analysis investigates the impact on fly ash/dolomite-based-geopolymer with various molarities of sodium hydroxide solutions which are 6 M, 8 M, 10 M, 12 M and 14 M. The samples of fly ash/dolomite-based-geopolymer were prepared with the usage of solid to liquid of 2.0, by mass and alkaline activator ratio of 2.5, by mass. After that, the geopolymer was cast in 50 × 50 × 50 mm molds before testing after 7 days of curing. The samples were tested on compressive strength, density, water absorption, morphology, elemental distributions and phase analysis. From the results, the usage of 8 M of NaOH gave the optimum properties for the fly ash/dolomite-based geopolymer. The elemental distribution analysis exposes the Al, Si, Ca, Fe and Mg chemical distribution of the samples from the selected area. The distribution of the elements is related to the compressive strength and compared with the chemical composition of the fly ash and dolomite.

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