A HYPOTHESIS ON CARBONATION SHRINKAGE

AN HYPOTHESIS IS PRESENTED OF THE MECHANICS OF CARBONATION SHRINKAGE IN TERMS OF THE MECHANICS OF ORDINARY SHRINKING AND SWELLING AND THE STRUCTURE OF HARDENED PORTLAND CEMENT PASTE. THE PRINCIPAL FEATURE OF THE HYPOTHESIS AS APPLIED TO PORTLAND CEMENT PASTE IS THAT CARBONATION SHRINKAGE IS THE RESULT OF DISSOLUTION OF CALCIUM HYDROXIDE CRYSTALS WHILE THE CRYSTALS ARE UNDER PRESSURE, AND THAT CARBONATION DOES NOT CAUSE SHRINKAGE IF IT OCCURS WHEN THERE IS NO PRESSURE ON THE CALCIUM HYDROXIDE CRYSTALS; CARBONATION OF OTHER HYDRATION PRODUCTS DOES NOT INVOLVE DISSOLUTION AND THEREFORE PRODUCES NO SHRINKAGE. ALSO DISCUSSED IS THE POSSIBLE ADVANTAGE OF CAUSING CARBONATION WHILE A SPECIMEN IS AS NEARLY SATURATED AS IS FEASIBLE. /PCA/

• Authors:
  • Powers, T C
• Publication Date: 0

Media Info

• Serial:
  • Portland Cement Assoc R & D Lab Bull
  • Issue Number: 0

Subject/Index Terms

• TRT Terms: Calcium compounds; Carbonization; Hardness; Hydroxides; Pastes; Portland cement; Pressure; Rock crystals; Shrinkage; Swelling
• Subject Areas: Highways; Materials;

Filing Info

• Accession Number: 00213586
• Record Type: Publication
• Source Agency: Portland Cement Association
• Report/Paper Numbers: No 146
• Files: TRIS
• Created Date: Jun 1 1970 12:00AM