A design experiment of mortar compressive strength with different water content and different ultra fine fly ash content

This paper investigates a design experiment of mortar used to analyse the material content factor on its compressive strength. The factor analyzed were ultra fine fly ash content and w/binder ratio. The ultra fine fly ash was produced by grinding with micronizer, a jet mill, using compressed air or gas to produce particles fineness range from 0.5 to 45 microns. In addition, the ultra fine fly ash factor contained low and high values, 20% and 50% by mass of cement replacement respectively whereas w/binder ratio factor had 2 values 0.3 and 0.35. Four different mix proportions were employed to cast 50 mm mortar cubes. The mortar was tested to find their compressive strength after 28 days and 56 days of curing. The result showed at the age of 28 days, both factors have shown only slight influence on the mortar compressive strength (the fly ash size of effect is 1.40 and the w/binder ratio size of effect is 1.13). However, at the age of 56 days the differences of ultra fine fly ash content gave greater effect on mortar compressive strength than the difference of the w/binder ratio (the fly ash size of effect is 2.96 and the w/binder ratio size of effect is 1.41).