Concrete contractors should be experienced in all these types of concrete and should be able to determine when it is appropriate to use them. Some contractors might even be able to use recycled glass as an aggregate to add a visual element to the concrete. The possibilities are virtually endless.



When concrete contractors simply follow the mixing instructions on a packet of cement using sand or an aggregate they get regular concrete, which may have strength of 10MPa to 40MPa depending on what it is going to be used for. Structural concrete should be 40MPa, while for something like blinding 10MPa would be appropriate. High strength concrete, on the other hand, can be made by lowering the water-to-cement ratio to 0.35 or lower and sometimes adding Silica to prevent the formation of free calcium hydroxide crystals. This is more appropriate for projects that require a compressive strength of usually more than 6000 pounds per square inch, or 40 MPa.

The idea of high performance concrete is pretty new. Concrete contractors can use this classification to describe any slab of concrete that conforms to a certain set of standard. These may include strength, density, toughness, volume stability, long life in severe environments, long term mechanical properties, compaction without segregation, ease of placement, early age strength, permeability, and heat of hydration.

Shotcrete is another fairly new concept, which is often used against rock surfaces or vertical soil where formwork is not necessary. Concrete contractors use this type of concrete for rock support in tunneling and other applications. There are wet and dry mix techniques for shotcrete, but in either case additives such as fiber reinforcement and accelerators may be used.

Luckily, contractors know which type of concrete should be used depending on the application.