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Wyszukujesz frazę "Rafiza, Abd Razak" wg kryterium: Autor


Wyświetlanie 1-2 z 2
Tytuł:
Setting Time and after Setting Properties of High Calcium Fly Ash Geopolymers with Different Concentration of Sodium Hydroxide
Autorzy:
Mohamed, Rosnita
Razak, Rafiza Abd
Abdullah, Mohd Mustafa Al Bakri
Sofri, Liyana Ahmad
Aziz, Ikmal Hakem
Shahedan, Noor Fifinatasha
Powiązania:
https://bibliotekanauki.pl/articles/2106582.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
high calcium fly ash geopolymers
setting time
heat evolved
early age properties
concentration of sodium hydroxide
Opis:
Setting time in geopolymers is known as the time taken for the transition phase of liquid to solid of the geopolymer system in which is represented in the initial setting and final setting. Setting time is significant specifically for application in the construction field. This study intends to determine the setting time of high calcium fly ash geopolymers and the properties of the geopolymers after setting (1-day age). This includes the determination of heat evolved throughout geopolymerization using Differential Scanning Calorimeter. After setting properties determination includes compressive strength and morphology analysis at 1-day age. High calcium fly ash was used as geopolymer precursor. Meanwhile, for mixing design, the alkali activator was a mixture of sodium silicate and sodium hydroxide (concentration varied from 6M-14M) with a ratio of 2.5 and a solid-to-liquid ratio of 2.5. From this study, it was found that high calcium fly ash geopolymer with 12M of NaOH has a reasonable setting time which is suitable for on-site application as well as an optimal heat evolved (-212 J/g) which leads to the highest compressive strength at 1-day age and no formation of microcracks observed on the morphology. Beyond 12M, too much heat evolved in the geopolymer system can cause micro-cracks formation thus lowering the compressive strength at 1-day age.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 2; 563--567
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties and Morphology of Fly Ash Based Alkali Activated Material (AAM) Paste Under Steam Curing Condition
Autorzy:
Razak, Rafiza Abd
Izman, Sharifah Nur Syamimi Syed
Abdullah, Mohd Mustafa Al Bakri
Yahya, Zarina
Abdullah, Alida
Mohamed, Rosnita
Powiązania:
https://bibliotekanauki.pl/articles/28099518.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
alkali activated material
AAM
geopolymer
fly ash
steam-cured
high-Fe
Opis:
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.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 2; 785--789
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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