A simple recipe with many variables
Concrete is a carefully balanced mix of cement, aggregates and water. Cement acts as the binder and modifies the characteristics and uses of concrete:
- Portland cement is used to make reinforced concrete,
- blended Portland cement is used for slabs and roads,
- other types of cement are usually reserved for work that does not require particularly high resistance to heat.
Aggregates, another essential ingredient in concrete, retain the intrinsic properties of the rocks that they come from. The color and chemical and physical characteristics of aggregates have a direct impact on the durability, esthetics and mechanical properties of concrete.
Additives for customized concrete
Additives can be incorporated in small amounts (less than 10 kg/m³) to give concrete specific characteristics:
- water reducers do not have an impact on the quality of the concrete but they do make it more fluid. They also allow concrete to be manufacturing with less water,
- superplasticizers, also called fluidifiers, enhance fluidity and are used to produce self-placing (Agilia®) and self-leveling concretes,
- water repellents produce concretes that are impermeable,
- air-entraining agents allow concretes to withstand frost and deicing products,
- setting agents accelerate hardening so that forms can be stripped sooner,
- retardants increase the amount of time during which a concrete can be worked.