Concrete doesn’t need any introduction.
Because, wherever we go, we see many concrete structures around us.
Concrete is a composite material with changeable properties.
The ingredients mixing ratio of concrete is variable and depends on the properties of ingredients and mix design.
A popular measuring method of concrete ingredients during mixing is by volume. But the weight measuring method is more accurate.
However, concrete is prepared by mixing three basic ingredients.
- Binding material
- Aggregate, and
#1. Binding material:
The most commonly used binding material for concrete is Portland cement. Other binding materials used for this purpose, are lime, fly ash, silica fume, etc. The selection of cement for concrete depends on the cement properties.
Two types of aggregates are used in concrete. Coarse aggregate and fine aggregate.
Coarse aggregate: Big sizes aggregates in concrete are coarse aggregates. The size of it varies between ½” to 1½” depending on the concrete mix design. Generally, crushed stone or brick chips are used as coarse aggregate.
Fine aggregate: The smaller size aggregates in concrete are Fine aggregates. The FM (Fineness Modulus) of fine aggregates can be between 1.2 to 2.5 depending on the mix design. We use sand as fine aggregate in concrete.
Read More: Properties of aggregate
The most important concrete ingredient is water. Water can decrease and increase the concrete strength. Water just starts and continues the chemical reaction of cement. The high water content in the concrete mix increases the workability of concrete but decreases the strength. On the contrary, low water content increases the concrete strength but makes concrete less workable.
Other than these, there are some other ingredients used in the concrete mix such as Admixture. Those are secondary ingredients and added to give concrete a certain property.
Editor’s Note: This post was originally published in May 2013 and has been completely revamped and updated for accuracy and comprehensiveness.