Abstract:
This research studies the mechanical properties of lightweight cellular rubber
wood fly ash geopolymer mortar. Rubber wood fly ash is a by-product of a power plant in
Songkhla Province. This research used ratios of sand (S) to rubber wood fly ash (RWFA) to
Portland cement (PC) of 50:50:0, 50:45:5, 50:40:10, 50:35:15, 50:30:20, 50:25:25 and 50:20:30.
Foam volume ratios of 0, 1, 3 and 5 percent. Sodium silicate solution (Na2SiO3; NS) to
sodium hydroxide solution. (NaOH; NH) ratio of 70:30 and the concentration of NaOH
solution was equal to 8 molars by testing the setting time, unit weight, compressive
strength. Thermal conductivity and Scanning Electron Microscopy/Energy Dispersive X-ray
Spectrometer (SEM/EDX) of lightweight cellular rubber wood fly ash geopolymer mortar
with curing ages of 7, 28, 60 and 90 days.
The results of the study found that the compressive strength tends to increase
with increasing PC content. The ratio that gives the highest compressive strength is the
S:RWFA:PC ratio of 50:25:25. The unit weight value and the thermal conductivity tends to
increase as the PC content increases as well. But the setting time tends to decrease as the
amount of PC increases. Increasing the amount of foam affects the unit weight. Compressive
strength coefficient of thermal conductivity of lightweight cellular rubber wood fly ash
geopolymer mortar There was a significant decrease. From SEM/EDX analysis. It was found
that by analyzing the distribution of elements using Mapping analysis, the weight and
composition of the atoms were uniformly distributed at the microscopic level. From the
EDX map, the main element compositions were Si, Al, Ca, Na and O, which tended to be
additional hydration components that may coexist with the geopolymer product form
calcium aluminosilicate hydrate (C-A-S-H) and sodium aluminosilicate hydrate. (N-A-S-H)