The strength properties of alkali-activated silica fume mortars

Abstract

In this study, the strength properties of alkali-activated silica fume (SF) mortars were investigated. The crushed limestone sand with maximum size of 0-5 mm and the sodium meta silicate (Na2SiO3) used to activate the binders were kept constant in the mortar mixtures. The mortar specimens using the replacement ratios of 0, 25, 50, 75 and 100% SF by weight of cement together with Na2SiO3 at a constant rate were produced in addition to the control mortar produced by only cement. Moreover, the mortar specimens using the replacement ratio of 4% titanium dioxide (TiO2) by weight of cement in the same mixture proportions were produced. The prismatic specimens produced from eleven different mixtures were de-moulded after a day, and the wet or dry cure was applied on the produced specimens at laboratory condition until the specimens were used for flexural strength (ffs) and compressive strength (fc) measurement at the ages of 7, 28 and 56 days. The ffs and fc values of mortars applied the wet or dry cure were compared with the results of control mortar. The findings revealed that the fc results of the alkali activated 50% SF mortars were higher than that of mortar produced with Portland cement only. It was found that the ffs and fc of alkali-activated SF mortars cured in dry condition was averagely 4% lower than that of alkali-activated SF mortars cured in wet condition.