This paper describes a new technology that allows normal-portland-cement based concrete to reach rapid early-flexural strength and thus reduce closure time when making pavement repairs. The system uses polycarboxylate high-range water-reducing admixtures, coupled with a nonchloride accelerator and a patented hydration control additive to achieve high strength very quickly. The experimental program described in this paper began in the laboratory and continued concurrently in the field to validate lab test results. Several chemical admixtures were selected for the initial laboratory tests. The primary factors evaluated were the hydration control admixture dosage, the polycarboxylate formulation, the nonchloride accelerator chemistry and the accelerator dosages. Results showed that most of the test mixtures reached the targeted flexural strength of 400 psi at 5h after mixing began. High early strength did not compromise later-age strength development. Higher air contents were shown to affect both early-age compressive and flexural strength. However, a significant early-age strength was obtained when sufficient air is entrained. The field test from interstate repair work showed that the concrete developed the required flexural strength at 400 psi at 4 h after placement. Specific procedures for producing the concrete are recommended based on the field and laboratory results. The key to producing this concrete is shown to be a relatively low water-cementitious material ratio coupled with proper admixture selections based on the materials employed and the application involved.


  • English

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 77-82
  • Serial:
    • Concrete International
    • Volume: 25
    • Issue Number: 8
    • Publisher: American Concrete Institute (ACI)
    • ISSN: 0162-4075

Subject/Index Terms

Filing Info

  • Accession Number: 00961790
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Aug 4 2003 12:00AM