Effects of granulated blast furnace slag trass and limestone fineness on the properties of blended cements

Delibaş, Tuğhan
The aim of this research was to determine the effects of the fineness of different mineral additives on loss on ignition, heat of hydration, physical, mechanical and chemical properties of blended cements. For that purpose, portland cement clinker was replaced with granulated blast furnace slag (GBFS), natural pozzolan (NP) and limestone (L) at 6%, 20% and 35% replacement levels. Blended cements containing GBFS and NP were ground to a fineness of 3000, 5000 and 6000 cm2/g. Cements containing L were ground to 3000 cm2/g, 4000 cm2/g and 4500 cm2/g. All of the blended cement types mentioned above were both interground and separately ground to the specified fineness levels. Therefore, a total of 57 different cements were produced. Loss on ignition, heat of hydration, chemical, mechanical and physical analyses were performed on the produced cements. Moreover, the chemical analyses of the cements were obtained for cement particles finer (-45μm) and coarser (+45μm) than 45 μm in order to determine the ingredients of -45 μm, which is known to be more reactive. As a result it was shown that the grindability differences of the cement ingredients affect the properties of blended cements. An increase in the specific surface area increases both the compressive strength and heat of hydration values and adversely affects the loss on ignition values. The results also showed that if the cement particles were ground finer, it was more prone to moisture which resulted in higher loss on ignition values after longer periods.