The use of chemical admixtures such as water reducers, retarders, high-range water reducers or superplasticizers are common in High Strength Concrete.
They make more efficient use of the large amount of cementitious material in high-strength concrete and help to obtain the lowest practical water to cementing materials ratio.
Chemical admixture efficiency must be evaluated by comparing strengths of trial batches.
Also, compatibility between cement and supplementary cementing materials, as well as water-reducing and other admixtures, must be investigated by trial batches.
From these trial batches, it will be possible to determine the workability, setting time, and amount of water reduction for given admixture dosage rates and times of addition.
The use of air-entraining admixtures is not necessary or desirable in high-strength concrete that is protected from the weather, such as interior columns and shear walls of high-rise buildings.
However, for bridges, concrete piles, piers, or parking structures, where durability in a harsh environment is required, entrained air is mandatory.
Because air entrainment decreases concrete strength of rich mixtures, testing to establish optimum air contents and spacing factors may be required.
Chat with a concrete engineer today about your project:
Comments