الفهرس 
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Abstract
The specific effects of water-reducing and retarding admixtures vary with different cements, water-cement ratio, type of coarse aggregate, an concrete mix proportions.
The major effect on both properties of fresh and hardened concrete are :
1) Water reduction :
Water-reducing and retarding admixtures, type D, reduce the water required for the same consistency (slump) of concrete up to 16 present. Concrete containing polyhydroxylated carbon acid or lignosulfonate admixtures generally requires 8 – 16 percent less water than dose concrete without the admixture. Water reduction reduces the water-cement ratio for a given cement ratio for a given cement content or permits a reduction in cement content while maintaining the same water-cement ratio
2) Setting time:
Lignosulfonates and polyhydroxylated carbon acids retard setting times 1 to 3 hrs when used at temperatures of 33c. When admixture is used, the dosages should be adjusted to meet the job conditions.