Influence of mixing time on the mechanical properties of self compacting concrete

The paper reports the results of experimental tests conducted on Self Compacting Concrete (SCC) to be used in a strengthening intervention on five historical r.c. columns made by using the Hennebique technique. In particular, the testing program was aimed at investigating the effect of mixing time on the rheological and on the mechanical properties of SCC. Therefore, seven sets with eight companion specimens characterized by two different water-to-cement ratios were tested by performing standard tests, i.e.: Compressive Strength, Slump Flow, Slump and V-funnel. The variable within each set was the mixing duration, that was varied from 2 to 30minutes. The experimental results underline how the choice of an appropriate mixing time allow to optimize both the material compressive strength and the filling ability of SCC, thus reducing the execution times of the works, as well as the construction costs.