The rheological properties of an SCC mixture

The rheological properties of an SCC mixture containing a certain type and amount of SCC can be affected by the test methods (such as rheometer type) and material characteristics. Therefore, it should be kept in mind that the following conclusions were derived for the materials used and tests applied in this study:(1)SCC mixtures containing various mineral admixtures were highly stable and moderately stable (VSI between 0 and 1) at 0 min according to ASTM C 1611. However, mixtures containing FAC, FAF and BFS exhibited some bleeding and Rapamycin at 50 min while there was no significant change in the stability of SF and MK blended mixtures after 50 min of rest.(2)T50 flow time of almost all mixtures after 50 min of rest (except 18BFS and 8SF18FAC18BFS mixtures) increased approximately 2 times compared to 0 min. MK and FAC were the two mineral admixtures that had most significant effect on T50 with time especially when they were incorporated at high replacement levels.(3)Mixtures containing MK and FAC, showed significant increase in torque plastic viscosity with time. Torque plastic viscosity of the mixtures incorporating SF displayed comparable behavior to that of the control mixtures with time. Moreover, torque plastic viscosity was reduced in time when BFS was incorporated in binary and quaternary systems. In addition, FAF did not show significant effect on plastic viscosity values as function of time.(4)Good correlations were established between T50 flow time and torque plastic viscosity values, irrespective of the duration of rest period.(5)In contrast to torque plastic viscosity values, apparent yield stress values increased with time for all SCC mixtures; however, no clear trend was depicted with the replacement level of the mineral admixtures. Similar to torque plastic viscosity values, MK and FAC blended mixtures had significant influence on yield stress with elapsing time. Increase in yield values were more pronounced in comparison with torque plastic viscosity values after 50 min of elapsing time.(6)Increase in thixotropy with time for the SF and MK blended mixtures were higher when compared to the control mixtures and the mixtures containing other mineral admixtures (FAC, FAF and BFS). The highest increase was observed in 36MK mixture whose thixotropy at 50–80 min time period was approximately 32% greater than the thixotropy of the same mixture at 0–30 min.(7)SF and MK significantly increased the compressive strength of the mixtures. The highest compressive strength was observed in 8SF18BFS mixture whose compressive strength was approximately 52% greater than of the control mixture. The partial replacement of PC by FAF decreased compressive strength of control mixtures while the compressive strength of FAC mixtures was found to be higher than control mixtures.