Concete Properties

Basic desired properties of concrete:

1. Workability
2. Cohesiveness
3. Strength
4. Durability

Workability means how easy to it is to place, handle, compact & finish a concrete mix. Concrete that is dry may be difficult to handle, place, compact & finish and, if not constructed properly, will not be as strong or durable when finally hardened. A slump test can be used to measure the workability of concrete. To make a more workable mix, we should add more cement paste, use well graded aggregates and use an admixture. (Never try to make a mixture more workable by just adding more water because this lowers the strength and durability of concrete.)

Strength and Durability. Well made concrete is a naturally strong and durable material. It is DENSE, reasonably WATERTIGHT, able to resist changes in TEMPERATURE, as well as wear and tear from WEATHERING. Concrete durability INCREASES with strength. Too much water and not enough cement will affect the concrete become weaker and less durable.

Cohesiveness. Cohesiveness is how well concrete HOLDS TOGETHER when plastic. It also affected by the grading of aggregate. Graded aggregate means that there is a range of size of aggregates, from large
rocks to small sands.Well-graded aggregates give a more cohesive mix, too much coarse aggregate gives a boney mix. Besides that, water content is also one of the issue. A mix that has too much water will not be cohesive and may separate and bleed.