THE QUANTITATIVE EVALUATION OF THE WATER/CEMENT RATIO USING FLUORESCENCE MICROSCOPY

This paper presents a method of determing the water/cement ratio in concrete, using polished light reflecting specimens. The specimen of concrete is first cast in clear resin. One to two mm is then cut from the face of the specimen to remove any surface resin and the specimen is polished to 3 micro m diamonds, and then vacuum impregnated with 0.0004 molar fluorescein soduim in alcohol. The specimen is then observed under a fluorescence microscope using the technique of Ploem and Tanke and the voltage of emitted fluorescent light is recorded. Plots of voltages of emitted fluorescent light against the water cement ratio of known standard specimens provide regression equations with which to calculate this ratio for test specimens. The parameters covered in this experiment were 0.3-0.4 for the water cement ratio of hardened cement paste; 0.25-0.65 for the water cement ratio of mortar; and 1/1-4/1 for the fine aggregate/cement ratio of mortar. A better prediction of the water/cement ratio from the voltage of emitted fluorescent light can be achieved by including the fine aggregate/cement ratio as a separate parameter in the regression equation. A limited assessment of the method has indicated that it can be used accurately within the parameter ranges: water/cement ratio 0.39-0.79; total aggregate/cement ratio 4.1-7.8; and fine aggregate/cement ratio 1.6-3.5.

  • Availability:
  • Corporate Authors:

    Thomas Telford Limited

    London,   United Kingdom 
  • Authors:
    • Mayfield, B
  • Publication Date: 1990-3

Language

  • English

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00604754
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Feb 28 1991 12:00AM