INTERACTION OF HARDENED CEMENT PASTE AND WATER

ADSORPTION OF WATER VAPOR ON A CLEAN SURFACE CHANGES THE SURFACE FREE ENERGY. IT IS SHOWN THAT, USING THE GRIFFITH CRITERION, THE CHANGE OF STRENGTH AS FUNCTION OF MOISTURE CONTENT CAN BE EXPLAINED BY ASSUMING A CHANGE OF SURFACE ENERGY. IN COLLOIDAL PARTICLES SURFACE ENERGY CREATES CONSIDERABLE HYDROSTATIC PRESSURE. A CHANGE IN ELASTIC MODULUS AND SHRINKAGE AS WELL AS SWELLING CAN BE RELATED TO A CHANGE IN HYDROSTATIC PRESSURE IN INDIVIDUAL GEL PARTICLES. CREEP IS AFFECTED PRIMARILY AT THE HIGHER RELATIVE HUMIDITIES. THE MAIN PARAMETERS OF A PROPOSED MODEL FOR HYDRATED PORTLAND CEMENT ARE SURFACE FREE ENERGY AND DISJOINING PRESSURE. ON THIS BASIS THE MECHANICAL BEHAVIOR OF HARDENED CEMENT PASTE IS DISCUSSED. A PHASE TRANSITION OF ADSORBED WATER NEAR 90 DEGREES C IS DISCUSSED. THE INFLUENCE OF THIS EFFECT ON THE MECHANICAL BEHAVIOR OF HARDENED CEMENT PASTE CAN BE UNDERSTOOD WHEN A CHANGE IN INTERFACIAL ENERGY IS TAKEN INTO CONSIDERATION. /AUTHOR/

• Authors:
  • Wittmann, F H
• Publication Date: 1973-8

Media Info

• Features: Figures; References;
• Pagination: p. 409-15
• Serial:
  • American Ceramic Society Journal
  • Volume: 56
  • Issue Number: 8
  • Publisher: f Public Works

Subject/Index Terms

• TRT Terms: Adsorption; Creep; Elasticity (Mechanics); Hydrostatic pressure; Interfaces; Mechanical properties; Moisture content; Portland cement; Strength of materials; Surface energy
• Old TRIS Terms: Adsorbed moisture
• Subject Areas: Highways; Materials;

Filing Info

• Accession Number: 00214304
• Record Type: Publication
• Files: TRIS
• Created Date: Apr 11 1974 12:00AM