Characterization and evaluation of alkaline activated mortars synthesized from binary and ternary blends of palm oil fuel ash, ground granulated blast furnace slag and fly ash
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Date
2018-08-01
Authors
Othman Mosbah Mohamed Elbasir
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Abstract
Palm oil fuel ash (POFA) with different fineness (t-POFA, f-POFA and u-
POFA) has affected the compressive strength and the microstructure of the POFAbased
alkaline activated mortars. The ultrafine POFA (u-POFA) alkaline activated
mortar mixture exhibits the highest compressive strength measured between 7 and 28
days of age. Various analyses techniques (XRD, FTIR, and FESEM-EDX) were
performed on the samples which showed the formation of C–S–H and N–A–S–H.
Comparison has been made for individual POFA, FA and GGBFS as alkali activated
mortars using Taguchi method. The results showed that the highest compressive
strength at 28 days of curing individual POFA, FA and GGBFS as alkali activated
mortars are 41.20 MPa, 51.14 MPa, and 93.97 MPa, respectively. This high
compressive strength can be attributed to the formation of gel binder (C–S–H and N–
A–S–H) in the alkali activated mortars, as proven by XRD, FTIR and FESM-EDX
analyses. The binary and ternary blended alkaline activated mortars of three
materials (POFA, FA and GGBFS) showed significant compressive strength
improvement when added to about 25 wt% u-POFA for the binary blend. However,
in ternary the highest strength obtained from 40 wt% u-POFA, 20 wt% FA and 40
wt% GGBFS. This research confirmed that the alkali activated mortar developed in
this study has superior performance when exposed to various aggressive
environments and exhibited high thermal stability when exposed to elevated
temperature up to 1000 °C.