Investigation of rheological properties of cementitious systems containing different C3A content containing metakaolin

In this thesis, the effect of cement C3A content and metakaolin (MK) utilization rate on the fresh and hardened state properties of cementitious systems were investigated. Setting time and flow properties of paste mixtures and high range water reducing admixture demand to provide the target flow value, consistency retention performance and compressive strength of mortar mixtures were determined. In addition, rheological measurements of cement paste mixtures were carried out with the loop method, immediately after the mixture was prepared and after waiting for 20 minutes in order to examine the change of rheological parameters depending on time (thixotropy). In this regard, the effects of pre-shearing procedure, mixing time, applied maximum deformation rate and deformation rate increase in 1 second on the thixotropic behavior of the mixtures were investigated. Marsh-funnel flow time values of paste mixtures increased with the increase of cement fineness and MK utilization ratio. In cases where the water reducing admixture utilization rate is low, a decrease in the mini-slump values of the mixtures was observed with the increase in the MK usage rate. It was determined that the structural recovery area values of all mixtures were higher than that of the structural deterioration area values. It was understood that the dynamic yield stress, final viscosity and structural recovery area values increased with the increase in C3A ratio, MK usage rate and cement fineness. This behavior was more pronounced by elapsed time. Irrespective of the cement C3A content and the MK utilization rate, the structure formation that occurred by elapsed time was mostly reversible. It was understood that the effect of C3A ratio on dynamic yield stress and viscosity values was more pronounced with the increase of pre-shearing rate, a increase of mixing time, a decrease of deformation rate. The flow values of the mortar mixtures decreased with the increase of cement C3A content and MK replacement ratio. With the increase of MK replacement ratio, the 28 and 90-day compressive strength values increased.