ACI says structural buildup at rest (SBR) is a rheological property that can affect the performance of self-consolidating concrete (SCC). The property should be optimised to intended placement condition. Adequate determination of SBR on the jobsite is important for quality control and necessitates the use of simple and robust testing methods.
The paper, written by Wael Megid and Kamal Khayat, discussed the ability of employing conventional workability test methods to evaluate SBR of SCC. Eight SCC mixtures designed to secure different SBR levels were investigated.
According to ACI: “SBR was determined using concrete rheometer and two field-oriented test methods: portable vane and inclined plane, as well as losses of slump flow, T50, and J-ring flow at rest. Correlations between SBR indexes determined from workability and rheological test methods were established.”
In addition: “Statistical models to predict static yield stress and SBR indexes as a function of workability loss at rest are proposed, which indicate that standard workability test methods can be used to evaluate SBR of SCC.”