Concrete Mixtures 10

Admixtures


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Admixtures are ingredients, other than Portland cement, that are added to the concrete mixture just before or during mixing. The types of admixtures used are air entraining, water reducing, retarding, accelerating and superplasticizer admixtures. Air entraining admixtures entrain or suspend, and spread small air bubbles throughout the concrete. Entrained air makes the concrete more resistant to damage caused by freezing and thawing, and surface scaling caused by deicers. It also increases concrete workability, and reduces bleeding and segregation. Water reducing strength increasing admixtures reduce the water needed to produce concrete at a required slump, reduce the ratio of water to cement, reduce the total amount of water and cement needed, and increase the slump. When the water to cement ratio is reduced, concrete strength increases. Water reducing admixtures can cause an increase in drying shrinkage, and, if the water to cement ratio is maintained while water is lost, a decrease in concrete compressive strength.


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 Concrete Mixtures Links

1.The Materials In Concrete.
2.Concrete Aggregates - Concrete Slump.
3.Concrete Placement - Vibration - Hydration.
4.Types of Portland Cement - Concrete Moisture & Cracking.
5.Watertight Concrete - Supplementary Cementing Materials.
6.Supplementary Cementing Materials.
7.Chemicals That Damage Concrete.
8.Concrete Aggregate Properties.
9.Angular & Smooth Aggregate Properties.
10.Admixtures.
11.Admixtures Continued.
12.Air Entraining Admixtures.
13.Air Entraining Admixtures Continued.
14.Conditions Affecting Concrete Air Volume.
15.Superplasticizers & Other Admixtures.
16.Ordering & Mixing Concrete.
17.Concrete Mixing - Subgrade Preparation.
18.Subbase Preparation - Concrete Placement.
19.Concrete Consolidation.
20.Concrete Finishing.
21.Concrete Curing.
22.Hot Weather Concreting.
23.Cold Weather Concreting.
24.Concrete Slump Test.

                                                     
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