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Influence of SiO 2 , Al 2 O 3 , CaO, and Na 2 O on the elevated temperature performance of alkali‐activated treated palm oil fuel ash‐based mortar
Author(s) -
Mijarsh Mustafa Juma A.,
Megat Johari Megat A.,
Abu Bakar Badorul H.,
Ahmad Zainal A.,
Zeyad Abdullah M.
Publication year - 2021
Publication title -
structural concrete
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 34
eISSN - 1751-7648
pISSN - 1464-4177
DOI - 10.1002/suco.201900302
Subject(s) - wollastonite , alkali metal , nuclear chemistry , molar ratio , nepheline , materials science , chemistry , mineralogy , catalysis , raw material , biochemistry , organic chemistry
The mechanical, physical, and chemical changes due to oxides molar ratios (SiO 2 /Al 2 O 3 and SiO 2 /CaO), and various Na 2 O concentrations of treated palm oil fuel ash (TPOFA)‐based alkali‐activated mortar (AAM) after being exposed to different elevated temperatures up to 1,000°C were investigated. The source materials (SMs) and alkaline activator (AA) were used as the main base material to produce the AAM. The SMs consist of TPOFA with and without mineral additives (Ca(OH) 2 , Al(OH) 3 , and silica fume (SF)). The AA was characterized by various Na 2 O concentrations of 7.1, 6.0, and 5.5% relative to the AAB weight. The results indicated that the relative compressive strength (CS) improved significantly from 9.20 to 34.62% after being exposed to 800°C. This was mainly due to the decrease in the total oxide's ratio of SiO 2 /Al 2 O 3 and SiO 2 /CaO from 14.84 and 6.98% to 4.27 and 2.03%, respectively. The relative CS has increased from 0.0 to 101.38% after exposed to 1,000°C when Na 2 O concentration reduced from 7.1 to 5.5%. This was due to the formation of more N–A–S–H and C–A–S–H gel binders as indicated at 28 days, which were transformed to nepheline (NaAl(SiO 4 )) and wollastonite (CaSiO 3 ) phases after exposure to 800°C and 1,000°C, respectively.