DISCOLORED CONCRETE FLATWORK ... THE CAUSES AND HOW TO MINIMIZE THEM

DISCOLORATION OF CONCRETE CAUSED BY CONCRETE MIX DESIGN & INGREDIENTS, AND CONCRETING PRACTICES BEFORE THE CONCRETE HAS HARDENED ARE REVIEWED. DISCOLORATION ARISING FROM THESE CAUSES ORDINARILY TAKE ONE OF THREE FORMS: (1) LARGE AREAS OF CONTRASTING COLOR, (2) BLACK SPOT OR DARK LEOPARD SPOTS AND (3) WHITE PATCHES CAUSED BY EFFLORESCENCE. FACTORS WHICH CAN RESULT IN SURFACE DISCOLORATION INCLUDE COLOR AND COMPOSITION OF THE CEMENT, WATER/CEMENT RATIO, CURING, ADMIXTURES, AND FINISHING PRACTICES. CAREFUL PREPARATION IS SUGGESTED TO AVOID DISCOLORATION BY: (1) DEVELOPING A UNIFORM NONADSORPTIVE SUBGRADE AND SCHEDULING CONCRETE DELIVERIES AND WORK CREW TO AVOID VARIATIONS IN PLACING AND FINISHING PROCEDURES, (2) AVOID ORDERING CONCRETE FROM MORE THAN ONE SOURCE AND AVOID THE USE OF CALCIUM CHLORIDE, ESPECIALLY IN CONCRETES WITH A LOW ALKALI CONTENT, (3) STANDARIZED CONCRETING AND FINISHING PRACTICES AND PROTECT THE CONCRETE BETWEEN FINISHING OPERATIONS, (4) TIME TROWELING TO PREVENT BURNING OF THE SURFACE AND (5) CURE THE CONCRETE THOROUGHLY AND UNIFORMLY, USING A WET-CURING TECHNIQUE, IF POSSIBLE. CORRECTIVE MEASURES ARE DESCRIBED FOR AREAS OF CONTRASTING COLOR, DARK SPOTS, LIGHT SPOTS, AND EFFLORESCENCE.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/05490219
• Supplemental Notes:
  • Vol 12, No 11, PP 417-420, 16 PHOT
• Publication Date: 1967-11

Media Info

• Serial:
  • CONCRETE CONSTRUCTION
  • Publisher: CEMENT & CONCRETE ASSOCIATION OF NEW ZEALAND
  • ISSN: 0549-0219

Subject/Index Terms

• TRT Terms: Admixtures; Calcium chloride; Cement; Color; Concrete; Concrete curing; Concrete finishing; Concrete placing; Mix design; Reviews; Standardization; Subgrade (Pavements); Water cement ratio
• Uncontrolled Terms: Discoloration; Efflorescence; Sources
• Old TRIS Terms: Concrete composition; Troweling
• Subject Areas: Construction; Highways;

Filing Info

• Accession Number: 00214790
• Record Type: Publication
• Files: TRIS
• Created Date: May 6 1994 12:00AM