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Self-consolidating concrete specifications spread

The fifth North American Conference on the Design and Use of Self-Consolidating Concrete, or SCC 2013, offered strong market and technical perspectives on one of the industry’s best value propositions to the architectural/engineering/construction community of the past two decades. Presenters at the mid-May event in Chicago demonstrated how stakeholders have compelled American Concrete Institute and ASTM International committees to develop guidelines and standards indicating self-consolidating mixes’ quality in plastic and hardened states.

Euclid Chemical Senior Vice President of Marketing and Technical Services William Phelan confirmed the continuing rise of SCC use in North America, success underscored by application on major projects including One World Trade Center in New York City. In “Self-Consolidating Concrete: Today’s Challenge and Tomorrow’s Prosperity,” he cites “15 by 2015,” a goal for SCC market penetration in ready mixed concrete as set by the Strategic Development Council SCC Initiative, which he chairs.

In an “An Overview of ASTM Standards Related to Self-Consolidating Concrete,” BASF Construction Chemicals Product Manager Mark Bury discussed the emergence of ASTM Subcommittee C09.47 on Self-Consolidating Concrete amid rising, early 2000s adoption of SCC, especially among precast producers. Further adoption for cast-in-place structures has confirmed the usefulness of four C09.47 products through 2012: C1758 Standard Practice for Fabricating Test Specimens with Self-Consolidating Concrete, addressing concerns that conventional concrete specimen methods do not necessarily suit SCC; C1611 Standard Test Method for Slump Flow of Self-Consolidating Concrete, monitoring the consistency and unconfined flow potential of fresh material in field or laboratory conditions; C1610 Standard Test Method for Static Segregation of Self-Consolidating Concrete Using Column Technique, measuring the coarse aggregate content in a cylindrical specimen’s top and bottom portions; and, C1712 Standard Test Method for Rapid Assessment of Static Segregation Resistance of Self-Consolidating Concrete Using Penetration Test, primarily gauging a mix’s segregation potential.

Bury also noted an ACI Certification Committee C610 feasibility study for an SCC Field Technician Certification program encompassing C1758, C1611, and C1712 methods. ACI C610 and ASTM C09.47 members would benefit from a review of the mix acceptance protocol Breckenridge Material Co., McCarthy Building Cos. and David Chipperfield Architects applied to St. Louis Art Museum East Building, whose coffer beam ceilings—as this month’s cover shows—are a stellar example of exposed, cast-in-place SCC.

As detailed in “Prescription for Performance” (pages 22-25), St. Louis market leader Breckenridge Material viewed the concrete contractor and design architect’s rigorous quality control/quality assurance requirements as an opportunity to emphasize technical and delivery competency. During 11 May–October 2012 pours totaling 1,600 yd. of SCC, the producer agreed to pre-load drum inspections and individual load sampling, typically by contractor and architect representatives, plus in-house technicians; one load only per truck per pour; and, provision of full back up fleet/plant redundancy, where 15 or more mixers were idled during each pour, but ready to load at a back up plant in the event of a main plant breakdown. The latter was required to ensure ready availability of consistent product for pour schedules averaging 90 minutes.
By helping the design and construction team achieve its target of drywall-grade smoothness and color uniformity at the St. Louis Art Museum East Building, Breckenridge Material has set a new standard for SCC in architectural conditions.