Cold-pressed fly ash geopolymers: effect of formulation on mechanical and morphological characteristics

Autor: Ong Shee-Ween, Heah Cheng-Yong, Liew Yun-Ming, Mohd Mustafa Al Bakri Abdullah, Ho Li Ngee, Lynette Wei Ling Chan, Ooi Wan-En, Nur Ain Jaya, Ng Yong-Sing
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Journal of Materials Research and Technology, Vol 15, Iss , Pp 3028-3046 (2021)
Druh dokumentu: article
ISSN: 2238-7854
DOI: 10.1016/j.jmrt.2021.09.084
Popis: This research uses low alkali activator content and cold pressing technique for fly ash-based geopolymers formation under room temperature condition. The geopolymers were prepared using four different parameters: fly ash/alkali activator ratio, sodium hydroxide concentration, sodium silicate/sodium hydroxide ratio and pressing force. The results indicated that the compressive strength (114.2 MPa) and flexural strength (29.9 MPa) of geopolymers maximised at a fly ash/alkali activator ratio of 5.5, a 14 M sodium hydroxide concentration, a sodium silicate/sodium hydroxide ratio of 1.5 and a pressing force of 5 tons (pressing stress of 100.0 MPa and 155.7 MPa for compressive and flexural samples, respectively). The degree of reaction (40.1%) enhanced the structure compactness with minimum porosity. The improved mechanical properties confirmed that a high strength pressed geopolymer could be formed at low alkali activator content without the aid of temperature.
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