In order to obtain mixtures that have (a) a consistency that would permit use of conventional placement equipment and (b) a water-to-cement ratio of 0-.33-0.37, melamine- and naphthalene-sulfonated polymer admixtures were used in the concrete placed in two experimental pavements and four bridge deck overlays. With one exception, ready-mix trucks were used to mix the concrete, and placement methods included direct discharge, buggy, crane and bucket, and pump. Internal vibration was used for consolidation, and the screeding equipment included a wooden straightedge, an oscillating screed, a rotating-drum screed, and a metal vibrating straightedge. Compression-tested specimens from the projects showed significantly higher early and 28-day strengths than specimens without the admixture, and petrographic examinations of cores taken from the overlays indicated that, on the average, the concrete was properly consolidated and controlled. However, because of the extreme variability of the concrete, many portions of the completed structures exhibited inadequate consolidation, segregated mixture components, improperly entrained air, shrinkage cracks, and poor finishes. Also specimens from freeze-thaw tests showed low durability factors that were attributed to an unsatisfactory air-voids system.

Media Info

  • Media Type: Print
  • Features: Figures; Photos; References; Tables;
  • Pagination: pp 19-28
  • Monograph Title: Superplasticizers in concrete
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00303960
  • Record Type: Publication
  • ISBN: 0309029708
  • Files: TRIS, TRB
  • Created Date: Mar 31 1980 12:00AM