HYGROMETRIC METHOD FOR DETERMINING THE MOISTURE CONTENTS OF POROUS MATERIALS

METODO HIGROMETRICO PARA A DETERMINACAO DE TEORESEM HUMIDADE DE MATERIAIS POROSOS

A method for determining in-situ moisture content has been developed in the Laboratorio Nacional de Engenharia Civil, Lisbon; it is based on the relation between relative humidity and moisture content is propus materials. A vibrating wire telehygrometer was used to measure the variations in length of hydroscopic materials when they absorb or lose humidity; the vibration frequency of the wire is dependent on the stress to which it is subjected (principle of the vibrating wire strain meters). The main conclusions of this study are as follows: 1. The field of application of this method is restricted to moisture contents corresponding to hygrometric conditions below saturation point. 2. Vibrating wire telehygrometers give good results only when the relative humidity is below 80 to 90%. If the fact that a drying or a wetting process is involved is known their precision can be improved. They are more accurate if they are calibrated for small moisture variations. 3. The hygrometric material so far used in telehygrometers (wood) although stable and durable has some disadvantages.

• Corporate Authors:

  National Civil Engineering Laboratory, Portugal

  Avenida do Brasil
  Lisbon 5,   Portugal 
• Authors:
  • Castro, E
• Publication Date: 1964-11

Language

• Portuguese

Media Info

• Features: Figures; References; Tables;
• Pagination: 6 p.

Subject/Index Terms

• TRT Terms: Humidity; Hygrometers; Hygroscopic coefficient; Moisture content; Porous materials; Vibrating wire transducers; Wetting
• Old TRIS Terms: Hygroscopic materials; Vibrating wire
• Subject Areas: Geotechnology; Highways;

Filing Info

• Accession Number: 00081044
• Record Type: Publication
• Source Agency: Transport and Road Research Laboratory (TRRL)
• Files: ITRD, TRIS
• Created Date: Mar 26 1975 12:00AM