Effect of slump cone orientation on the slump flow time (T50) and stability of sustainable self-compacting concrete containing limestone filler

Since the innovation of SCC, many test methods have been developed to characterize its fresh properties; however, only a few of these tests have been standardized by the ASTM. The slump flow test, standardized as ASTM C1611, is the simplest and most widely used test for both laboratory and field testing of SCC. In ASTM C1611, two filling procedures (A and B) pertaining to two different orientations of the slump cone are permitted. Although the two slump flows have similar values regardless of the filling procedure, the slump flow times (T50) measured using the two procedures are expected to be different. The ASTM considers the determination of T50 as a non-mandatory test to be used as a relative measure of flow rate, viscosity and stability. In the current work, a relationship between the T50 values of the two permitted filling procedures has been established. The theoretical background for this relationship is presented and discussed. A conversion factor of approximately 1.9 was found to shift from the timeframe used in procedure A to that in B. A case study showing the impact of applying the same T50 timeframe regardless of the filling procedure on the rheological properties of SCC is also presented.