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Bra AKTRK, Didem OKTAY
 


Keywords:



RHEOLOGICAL BEHAVIOR OF ALKALI ACTIVATED SLAG-BASED SYSTEMS: EFFECTS OF DIFFERENT MINERAL ADDITIVES
 
There has been increasing attention on the 3D printing application technology in concrete production to simplify the construction procedures in recent years. Compared with traditional concrete production systems, 3D printing technology requires the materials to satisfy some rheological property requirements. Generally, these requirements on 3D printing materials cause a need for increased cement content, which results in larger amounts of CO2 emissions. In this case, instead of cement-based systems, alkali-activated materials can be a good nominee since they exhibit short setting times, high ear-ly-age strength values, and arrange their rheology easily. The current study investigates the rheological properties of alkali-activated slag-based pastes containing different types of mineral additives. The effects of silicium-based mineral additives such as fly ash, metakaolin, and waste basalt powder on the rheology of systems are studied. Moreover, different types of activators, i.e., sodium hydroxide and sodium silicate, are used. The performance or microstructure of slag-based alkali-activated systems has already been investigated comprehensively in previous studies. However, the rheological properties of these systems have not been investigated in detail by researchers up to now. Moreover, the effect of waste basalt powder, one of the by-products obtained by stone crushers in basalt quarries, has not been studied. This study will test the rheological properties and performance of alkali-activated slag-based systems in terms of workability, static and dynamic yield stress, plastic viscosity, and compressive strength development as an initial step. A series of trial mixtures presented promising results that different types of silicium-based mineral additives, including basalt powder, can be used as a raw material for 3D print applications. Therefore, a set of experimental studies will be conducted to observe the effect of different additives and activator types on the rheological properties and compressive strength of these binder systems. It has been thought that this study will lead to a new alkali-activated binder system that may be used in 3D printing applications while utilizing waste mineral additives and contribute to sustainable and green binder design.

Anahtar Kelimeler: Rheology, Alkali activation, Mineral additives, Yield stress, Viscosity, Compressive strength