PHASE TRANSITIONS OF ADSORBATES: IV, MECHANISM OF FROST ACTION IN HARDENED CEMENT PASTE

THE DIMENSIONAL CHANGES AND THE THERMOGRAMS OF CEMENT SPECIMENS WERE DETERMINED DURING TEMPERATURE CYCLES (+5 TO -60 DEGREES C, 0.33 DEGREE C PER MINUTE). IN EACH CASE, FREEZING PROCESSES AT -8 AND -40 DEGREES C AND MELTING PROCESSES AT -11 AND 0 DEGREES C WERE OBSERVED. THE RESULTS COULD BE EXPLAINED BY A THEORY PREVIOUSLY DEVELOPED FOR THE POROUS-GLASS-WATER SYSTEM. AT THE HIGHER TEMPERATURE, FREEZING OCCURS ON THE OUTER SURFACE OF THE SPECIMEN; AT THE LOWER TEMPERATURE, IT OCCURS IN THE PORES AFTER REDISTRIBUTION OF THE WATER. BECAUSE WATER DOES NOT FREEZE IN PORES FILLED ON ADSORPTION, IT MIGRATES OUT OF THESE PORES WHEN THE RELATIVE HUMIDITY (EXPRESSED IN TERMS OF THE VAPOR PRESSURE OF UNDERCOOLED WATER), UNAVOIDABLY DECREASES ON COOLING. EXPANSION IS DELETERIOUS WHEN THE WATER CONTENT OF THE PASTE IS SIGNIFICANTLY GREATER THAN THE EQUILIBRIUM VALUE AT THE PREVAILING RELATIVE HUMIDTIY. THE EFFECTS OF THE WATER/CEMENT RATIO, DEGREE OF SATURATION, AIR ENTRAINMENT, SAMPLE DIMENSIONS, AND COOLING RATE WERE CONSISTENT WITH THE THEORY. /AUTHOR/

• Authors:
  • Litvan, G G
• Publication Date: 1972-1

Media Info

• Pagination: p. 38-42
• Serial:
  • American Ceramic Society Journal
  • Volume: 55
  • Issue Number: 1
  • Publisher: f Public Works

Subject/Index Terms

• TRT Terms: Adsorption; Concrete; Cooling; Freezing; Frost action; Pastes; Pores; Thermographs
• Uncontrolled Terms: Pores
• Old TRIS Terms: Adsorbates
• Subject Areas: Highways; Materials;

Filing Info

• Accession Number: 00214121
• Record Type: Publication
• Files: TRIS
• Created Date: Jun 11 1972 12:00AM