Ndị na-ahụ maka ụfụfụ na Concrete

Ihe mmepụta ihe dị ugbu a na-enye usoro ikuku n'ime ihe ngwakọta plastik. Ọdịnaya ikuku nke ihe ahụ bụ ihe dị mkpa nke na-emetụta ịdịte aka nke ihe ahụ. Proper air content should be established at rest and during mixing. If air content is lower than the desired level, the concrete may not meet the requirements of the project.

In order to control the air content of concrete, a variety of methods have been used. One method involves the addition of chemical admixtures. These chemical admixtures can reduce the need for water, control setting and shrinkage of the concrete, and inhibit corrosion.

Another method includes the use of surface active agents. Surface active agents have the ability to generate a head of foam when incorporated into water. These surface active agents typically have an alkyl ethoxylate composition and can be mixed into a plastic hydratable cementitious mix.

Alkyl alkoxylate based surface active agents have proven to be particularly effective when combined with polycarboxylate type cement dispersants. These polycarboxylate-type dispersants are characterized by their low number average molecular weights (HLB) nke 0.5 ka 5 pasent.

Various embodiments of the present invention involve the addition of an alkyl ethoxylate based surface active agent or an air entraining agent to a plastic hydratable cementitious mixture. The exemplary alkyl ethoxylate surface active agents can have between three and fifteen ethoxylate groups, optionally less than two propoxylate groups.

Plastic concrete mixes contain a mixture of a cementitious binder, fine and coarse aggregate, na mgbakwunye. Typical cementitious binder is ordinary Portland cement. Agbanyeghị, it can also be blended with other materials.