Microstructure characterization of fly ash-based geopolymer mortar with substitution of oil palm ash

摘要

Geopolymers were materials produced from the polymeric aluminosilicate geosynthesis and alkali-silicate that produce of a polymer fabric of SiO_4 and AlO_4 which were tetrahedral tethered. This paper presented the contents and microstructures of fly ash and oil palm ash geopolymers. The composition were mixture with fly ash ratio: oil palm ash = 100%: 0%, 75%: 25% and 50%: 50%, activator ratio: precursor = 0.417, NaOH ratio: Na_2SiO_3 = 2.0 with a molarity NaOH solution, of 8 M, 10 M, 12 M, 14 M and 16 M. The stages of this research include the preparation and testing of materials were used, preparation of alkali activator solution, mix design and casting process, maintenance and testing of Fresh mortar include testing of slump flow and setting time, while hard mortar includes mortar weight testing, compressive strength testing, and microstructure testing. Tests were performed at 3, 7, 14 and 28 days. The results of test was obtained a maximum compressive strength about 56.06 MPa on the composition of the FA mixture: AS = 100: 0-16 at 28 days. The microstructure of the geopolymer mortar were influenced by the concentration of NaOH solution and the application of oil palm ash.