Evaluation of Tests for Determining the Pumpability of Concrete Mixtures

摘要

This report evaluates two methods currently proposed for determining concrete pumpability: (a) the pressure bleed test method and (b) a checklist analysis which examines 10 variables of concrete mixtures and their effects on concrete pumpability. Part of the investigation consisted of a laboratory study in which 14 mixtures containing a combination of both rounded (natural) and angular (crushed) coarse aggregate, natural and manufactured fine aggregate, mineral admixtures, steel fibers, and a high-range water-reducing admixture were analyzed using both proposed procedures and then pumped. The other part comprised a field study in which two concrete mixtures were analyzed and then pumped at two project locations. One contained natural coarse and fine aggregate and the other contained manufactured coarse and fine aggregate. All concrete mixtures were air entrained. It was concluded that the pressure bleed test method is effective only in determining the pumpability of concrete using a poorly maintained and leaky pump. The checklist analysis, although conservative, is a better indicator of pumpability and should be considered for inclusion in an appropriate Engineer Manual or Engineer Technical Letter.