NPCA Committee revises benchmark SCC mix reference

Sources: National Precast Concrete Association, Carmel, Ind.; CP staff

Slump flow test

The National Precast Concrete Association Engineering & Technology Committee recently reviewed and updated their White Paper, “Guide to Implementing and Producing Self-Consolidating Concrete,” posted under Technical Resources here. It profiles highly flowable, yet stable mixes that readily fill formwork, settle without significant segregation, and require little to no consolidation. Authors discuss how SCC mixes can be ideal for use in precast elements and structures, but should be carefully designed to achieve required performance characteristics, properly placed, and cured. They also review the quality control essentials behind fresh SCC mix testing: ASTM C1610, C1611, C1621 and C1712, respectively indicating column segregation; slump flow and visual stability index; J-Ring flow (passing ability); and, static segregation.