SYMPOSIUM ON EFFECT OF WATER-REDUCING ADMIXTURES AND SET- RETARDING ADMIXTURES ON PROPERTIES OF CONCRETE

A WATER-REDUCING ADMIXTURE WHEN ADDED TO A CONCRETE PERMITS A REDUCTION IN MIXING WATER WITH NO LOSS IN SLUMP, OR IF THE WATER CONTENT IS MAINTAINED CONSTANT, PRODUCES AN INCREASE IN SLUMP. A SET-RETARDING MIXTURE REDUCES THE EARLY RATE OF HARDENING AND SO PERMITS THE CONCRETE TO BE HANDLED AND VIBRATED FOR AN ADDITIONAL PERIOD AFTER MIXING. BOTH CLASSES OF MATERIALS, THE LIGNOSULFONIC ACIDS AND THE HYDROXYLATED CARBOXYLIC ACIDS ALONG WITH THEIR RESPECTIVE SALTS, WHEN ADDED TO CONCRETE REDUCE THE WATER REQUIREMENT AND ALSO RETARD THE SET. MODIFICATIONS AND DERIVATIVES OF THESE MATERIALS MAY RETAIN THE WATER-REDUCING PROPERTY OF THE ADMIXTURE WITHOUT MODIFYING THE HARDENING RATE OR MAY EVEN ACCELERATE THE SET. THE SYMPOSIUM SELECTED INFORMATION ON ADMIXTURES ACCORDING TO THE FOLLOWING: (1) THE MECHANISMS BY WHICH THESE MATERIALS MODIFY CONCRETE PROPERTIES, (2) THE EFFECTS OF THE ADMIXTURES ON THE PROPERTIES OF PLASTIC AND HARDENED CONCRETE AND THE VARIATION OF THESE EFFECTS DEPENDING UPON THE OTHER MATERIALS INVOLVED, THE TYPE OF CONCRETE, AND THE EXISTING TEMPERATURE, (3) THE TYPE OF CONSTRUCTION AND THE CONDITIONS UNDER WHICH THEIR USE IS PARTICULARLY ADVANTAGEOUS, (4) THE PROBLEMS IN CONTROL AND APPLICATION BROUGHT ABOUT BY THEIR USE, (5) THE PROBLEMS OF PREPARING ADEQUATE PURCHASE SPECIFICATIONS, AND (6) RESEARCH UNDER WAY TO PRODUCE EVEN BETTER AND MORE RELIABLE ADMIXTURES ECONOMICALLY.

• Supplemental Notes:
  • No 266, 246 PP
• Publication Date: 1959

Media Info

• Serial:
  • Am Soc Testing & Matls Spec Tech Publ

Subject/Index Terms

• TRT Terms: Admixtures; Concrete; Concrete construction; Concrete curing; Concrete hardening; Lignin; Physical properties; Polymer concrete; Purchasing; Retarders (Chemistry); Slump test; Specifications; Temperature; Water reducing agents
• Uncontrolled Terms: Carboxylic acids; Concrete properties; Hardened concrete; Slumps
• Subject Areas: Freight Transportation; Highways; Materials;

Filing Info

• Accession Number: 00212702
• Record Type: Publication
• Files: TRIS
• Created Date: May 13 1994 12:00AM