When assessing the moisture state in a cementitious material, measuring the relative humidity (RH) is preferable to other methods due to its universal value in connection with comparisons between different materials, between different degrees of maturity and in connection with the influence of other adjacent materials. The use of capacitive RH meters requires an accurate and uniform methodology to achieve satisfactory accuracy and precision. A proposal for a methodology of this kind is provided in the present report. For materials at a very early age of maturity, the methodology has been developed for measuring the RH during 2 hours 45 minutes with an accuracy of up to +-1-1.7% RH. The use of capacitive RH meters requires that personnel be trained both in maintenance and measurement procedures. For many cementitious materials, it takes a long time (days or weeks, depending on external conditions and the thickness of the material) to obtain the original RH level after drilling measurement holes. Consequently, the insertion of test tubes directly after casting is recommended. If this is not possible, or if the climatic conditions at the measurement site are difficult, it is preferable to measure the RH on material specimens taken in situ. This measurement can be carried out in a suitable environment, for example in a laboratory. A detailed error analysis of the total measurement error is presented. This analysis can serve as a basis for calculations of the total measurement accuracy in connection with RH measurement under different external conditions and with different capacitive RH meters. (Author/TRRL)

  • Availability:
  • Corporate Authors:

    Umeaa Universitet

    Trafik-Och Transportforskningsenheten
    Solna,   Sweden 

    Cement and Concrete Research Institute

    Drottning Kristinas Vaeg 26
    Stockholm 70,   Sweden 
  • Authors:
    • Molina, L
  • Publication Date: 1990

Media Info

  • Features: References;
  • Pagination: 67 p.
  • Serial:
    • Trum
    • Issue Number: 90:3
    • Publisher: Umeaa Universitet
    • ISSN: 0280-1900

Subject/Index Terms

Filing Info

  • Accession Number: 00619751
  • Record Type: Publication
  • Source Agency: Swedish National Road and Transport Research Institute (VTI)
  • Report/Paper Numbers: 1990:1
  • Files: ITRD, TRIS
  • Created Date: Mar 31 1992 12:00AM