EFFECTS OF SUPERPLASTICIZERS ON PROPERTIES OF FRESH AND HARDENED CONCRETE

The purpose of this study was to determine the effects of four commercially available superplasticizers on concrete. In each case three basic mixes were compared: one control proportioned for 100-mm (4-in) slump and 0.50 water-to-cement (w/c) ratio, a second control proportioned for zero slump and 0.50 w/c ratio, and a mix compositionally identical to the second but with sufficient admixture to produce a slump of 100 mm (4 in). The design air content for all mixes was 7 plus or minus 1 percent, and the aggregate maximum size was 13 mm (0.5 in). Slump, air content, and unit weight were measured, as were initial and final setting times, compressive strength, flexural strength, freeze-thaw resistance, shrinkage, and creep. The four admixtures had quite distinct and different effects, but all induced varying degrees of slump los and caused a marked increase or decrease in air content immediately after addition that was followed by a gradual decrease with time. Some increased setting times by about 20 percent. Compressive strengths increased at all ages up to 28 days and in some cases at ages of six months and a year. Flexural strengths were essentially unaffected. All mixes achieved durability factors greater than 96 percent at 300 cycles, but distinct differences in linear expansion, weight loss, and degree of scaling were noted. Some of the admixtures increased shrinkage while others had little effect. Their influence on total creep was similar, although basic creep and drying creep were affected in opposite ways.

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 1-7
  • Monograph Title: Superplasticizers in concrete
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00303957
  • Record Type: Publication
  • ISBN: 0309029708
  • Files: TRIS, TRB
  • Created Date: Mar 31 1980 12:00AM