INTERNALLY SEALED CONCRETE

A process for internally sealing concrete was developed which prevents intrusion of chlorides and other corrosive compounds. Small particles of an inert thermoplastic sealant added to the initial concrete mix are later triggered by warming to fuse and flow into the fissures and capillaries of the cured structure. A low cost sealing additive was developed which fuses at moderate temperatures and, at 2-1/2% concerntration, completely blocked chloride penetration through ninety days ponding with a 3% NaCl solution. Particle shape was shown to affect the compressive strength of sealed concrete, and a process was developed to produce additive spheres for maximum strength. The process, using 3% additive based on concrete weight, was applied to the construction of a large scale demonstration slab 12 ft x 48 ft x 7.5 inches with reinforcing steel to simulate a bridge deck. A companion structure was constructed as a control with a standard concrete formulation. Tests were concluded after 60 days continuous ponding with a 3% NaCl solution, and indicate no penetration of the sealed sections. The control shows high chloride concentrations and potential changes indicate corrosion started after seven days exposure. /Author/

  • Supplemental Notes:
    • FHWA Contract Manager K.C. Clear. This study is a work in FCP Project 4B. "Eliminate Premature Deterioration of Portland Cement Concrete". See also PB-221 324
  • Corporate Authors:

    Monsanto Research Corporation

    800 North Lindbergh Boulevard
    St Louis, MO  United States 

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Jenkins, G H
    • BUTLER, J M
  • Publication Date: 1975-1

Media Info

  • Features: Appendices; Figures; Tables;
  • Pagination: 106 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00098446
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: FHWA-RD-75- 20 Final Rpt., FCP 34B1-202
  • Contract Numbers: FH-11-7884
  • Files: NTIS, TRIS, USDOT
  • Created Date: Sep 30 1976 12:00AM