Norm Wood held the attention of more than 300 concrete industry researchers and practitioners as he described his experiences promoting self-consolidating concrete (SCC) in western Canada. His message was bittersweet. Despite all the research on the topic, Wood was offering reasons why SCC has not yet gained more market acceptance.
Wood addressed the Third Symposium on SCC organized by Northwestern University's Center for Advanced Cement-Based Materials (ACBM). His speech represents a major turning point in SCC development.
Despite the lagging market acceptance, SCC is no longer viewed as a lab material. In nine years, the focus has increased exponentially. In the time since ACBM has been hosting these symposiums, the number of technical papers presented annually has grown from 90 to 900. And what encouraged symposium organizer Dr. Surendra Shah is that most of the papers presented at the November event in Chicago focused on work in the field and production.
Wood showcased several examples of well-executed SCC projects. But he provided an insider's view on why SCC has not had a greater impact in North America. One main reason is that placing contractors are waiting for the ready-mixed concrete industry to develop robust mixes that are consistent in quality and allow them to benefit economically from SCC's workability.
There was still some good news. After Wood's presentation, BASF Construction Chemicals' Joe Daczko said two recent surveys indicated industry acceptance has been slowly increasing. He reported that producer members of NRMCA responded that SCC accounted for 3.5% of all concrete deliveries last year. Daczko said the numbers were even higher for the precast industry. Producers reported substantially higher acceptance, suggesting that more than 50% of all precasters periodically use SCC.
The symposium's papers updated several important trends: mix designs, production/process improvement, pumping, formwork pressure, and quality control. It was evident that researchers have been studying how to enable contractors to increase casting rates and mitigate any potential formwork pressures.
Sponsors of the symposium were: BASF, Lafarge North America, Axim Italcementi, Euclid Chemical, Germann Instruments; Grace Construction Products, ICI Rheocenter, PCA, Schleibinger Geräte, Sika, Federal Highway Administration, ACI, Precast/Prestressed Institute, Rilem, and Hanley Wood. You can buy the proceedings on CD-ROM at www.scc2008.info.
With much of the SCC research originating in Europe, North American material engineers will be interested in the information offered at the Rilem International Symposium on Rheology of Cement Suspension Such as Fresh Concrete. Organized by ICI Rheocenter, the symposium takes place Aug. 19-21 in Reykjavik, Iceland. To learn more, visit www.rheo.is.