The choice of a concrete mix depends on the need of the project both in terms of strength and appearance and in relation to local legislation and building codes.
The design begins by determining the requirements of the concrete.
It is also called self consolidated concrete or flowing concrete.
Air-entrained concrete contains billions of microscopic air cells per cubic foot.
Properly designed SCC can save time and labor without sacrificing performance.
The compressive strength of a concrete is determined by taking standard molded, standard-cured cylinder samples.
A well distributed aggregate grading helps achieve SCC with reduced cementitious materials content and/or reduced admixture dosage.
Robustness can be regarded as the ability of the SCC mixture to maintain both the fresh properties and composition pre- and post-casting of one batch or successive batches, due to the composition of the mixture and due to some small changes in the contents of the ingredients of the mixture. 143-153, in Self-Compacting Concrete, Proceedings, 3rd Intern. By contrast, neither silica fume nor most types of fly ash can be considered as density modifiers. Sakata et al.[i] reported that SCC made with low w:p ratio of 0.33 (powder containing limestone filler), the incorporation of a small concentration of welan gum of 50 g/m3 can reduce the variability in slump flow of SCC due to changes in cement Blaine (318 to 342 m2/kg), fineness modulus of sand (2.08 to 3.06), and temperature of fresh concrete (10 to 30°C). The authors concluded that the slump flow value tends to prominently decrease with an increase in natural moisture content of fine aggregate for mixtures with 0.35 w:c ratio as opposed to 0.5 w:c ratio.
The amount of entrained air is usually between four and seven percent of the volume of the concrete, but may be varied as required by special conditions.
View Finishing Air Entrained Concrete for additional information.