Concrete mixes and their uses
It is important to get the right concrete mix for your construction project. Though all concrete mixes are composed of largely the same ingredients: water, aggregates, and cement, different concrete mixes contain different additives to promote certain properties and fit certain uses. Some common admixtures are:
- Set retarding – slows down the rate that concrete sets, useful for laying in high temperatures.
- Plasticisers – improves workability and flows freely.
- Accelerating – reduces concrete setting time.
- Corrosion inhibiting – slows rate of corrosion in reinforcing steel, reducing maintenance costs.
- Shrinkage reducing – prevents shrinkage and cracking during setting.
- Fibre reinforced – improves strength.
What driveways are often made of, this is the most common concrete mix available and is largely available from stores for personal use. It is mostly used in domestic projects, as it is not as sturdy as high-strength concrete. It usually withstands pressure between 10 MPa to 40 MPa, making it unsuitable for uses that need to handle heavy weight.
High Strength Concrete
Able to withstand pressure greater than 40 MPa, high strength concrete is suitable for use in high-rise buildings, bridges and foundations for its ability to withstand heavy loads. However, high strength concrete mixes can have workability problems, so admixtures, such as plasticisers, often need to be added to get around this.
Light Weight Concrete
As the name suggests, light weight concrete is much lighter than regular concrete, with a density of approximately 105 lbs per cubic foot, compared to regular concrete’s 150 lbs. This is achieved through the use of light weight, course and fine aggregates. It is used to reduce the overall weight of a structure whilst retaining the compressive strength of regular concrete. It also has improved fire resistant properties.