Multi-Electrode Conductivity Method to Evaluate Static Stability of Flowable and Self-Consolidating Concrete

In cement-based materials, coarse aggregate segregation can lead to heterogeneity in hardened material properties with direct mechanical properties and durability implications. Segregation control is especially critical in self-consolidating concrete (SCC) and flowing concrete, as well as in concrete made with fillers used for partial cement replacement or supplementary cementitious materials. The authors attempted to develop a rapid segregation estimation methodology during the dormant cement hydration period, monitoring changes through electrical conductivity in local composition over specimen height, as a time function. Multi-pair electrode conductivity method results were compared with those obtained through actual segregation study determined on hardened concrete samples through an image processing technique of tracing and counting, along hardened cylindrical sections, aggregate particles. In total, testing was done on 5 SCC mixtures with a slump flow value range of 650 and 880 mm (excessive) (25.6 to 34.7 inches) and 9 concrete mixtures with a slump value range of 70 to 240 mm (2.76 to 9.45 inches). A high correlation degree was established between electrical conductivity results and image analysis methods. Electrical conductivity data obtained after 20 minutes of testing are shown to correlate well with homogeneity, segregation and bleeding indexes determined from, at typically greater than 3 hours peak conductivity, an electrical conductivity approach, as well as an image analysis-determined segregation index. Static stability following concrete placement evaluation can be done nondestructively through the conductivity approach.

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  • Authors:
    • Khayat, Kamal H
    • Vanhove, Yannick
    • Pavate, Trimbak V
    • Jolicoeur, Carmel
  • Publication Date: 2007

Language

  • English

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Filing Info

  • Accession Number: 01055402
  • Record Type: Publication
  • Report/Paper Numbers: 104-M48
  • Files: TRIS
  • Created Date: Aug 14 2007 3:34PM