The effect of asphalt emulsion on the properties of fly ash based geopolymers

This research aimed to study the effect of asphalt emulsion (AE) on the properties of fly ash based geopolymers. Solid waste materials used for the production of geopolymer were coal fly ash (FA) 70 wt% and bagasse ash (BA) 30 wt%. Alkaline solution used for the geopolymerization reaction was the mixture of 10 M NaOH and Na 2 SiO 3 with the ratio of 1:2. The liquid and solid (L/S) ratios of 0.6, 0.7 and 0.8 were prepared. The AE of 1 wt%, 3 wt% and 5 wt% were added into the raw materials mixtures. Then, the mixed slurry was casted into a mold for the further tests. The setting time was determined using VICAT. After ageing of 7 day, 14 day, and 28 day, the compressive strength and modulus of rupture (MOR) samples were measured. The results of the study revealed that the sample with the L/S ratio of 0.7 had the best mechanical properties. The additional of AE up to 3 wt% led to an improvement of mechanical properties where the 1 wt% of AE gave the highest compressive strength, Young’s modulus and MOR. Bulk density and %water absorption, were determined. Phase structures, chemical structures and microstructures were observed using XRD, FTIR and SEM techniques, respectively.