Billed as a very innovative technology by CHRYSO, EnviroMix® is engineered to boost the performance of Supplementary Cementitious Materials (SCM).
SCMs are industrial by-products which when used as a partial replacement for Portland cement reduce the amount of cement that is required for concrete. And in so doing, the energy and CO2 impact of concrete is reduced. Significantly, if not used in concrete these waste materials would be consigned to valuable landfill space.
CHRYSO Enviromix® allows significantly higher clinker replacement using by-products, such as fly ash or slag, while maintaining the desired plastic and hardened concrete properties.
Eddie Correia, executive vice president at CHRYSO Southern Africa, says EnviroMix® was developed specifically for use in green concrete. “When constructing a building if the quantity of Portland cement is reduced at an average across all concrete mixes (between 15% and 60%) by substituting it with SCMs, a company can earn points towards a Green Star Rated building,” he says.
CHRYSO Enviromix® is based on proprietary and patented chemistries including a combination of specific cement dispersion technology with hydration catalysts.
Using SCMs in concrete has many advantages; they can improve permeability, increase the durability, reduce the potential for sulphate attack, reduce the heat of hydration and reduce the potential for alkali-silica reactivity.
However, Correia cautions that while the benefits of using CHRYSO Enviromix® technology are obvious, the curing of concrete is critical. As the percentage of SCM content increases in concrete, longer curing times may be needed.
It is, therefore, important to use a product from the CHRYSO Cure® range in order to protect the concrete until it reaches an adequate strength to counter shrinkage stresses. If working with concrete containing reinforced steel, it is also advisable to use a corrosion inhibitor such as CHRYSO® CI.
An in-depth understanding of local aggregates and cement by the CHRYSO Southern Africa team as well as the performance characteristics of EnviroMix® allows optimum design mixes to be recommended by CHRYSO Southern Africa. As part of the package, these design mixes undergo stringent testing both in the CHRYSO Southern Africa laboratory and on-site.
“Importantly, by optimising the concrete design mix using local materials and using EnviroMix® technology superior concrete placeability and finishability is ensured. Concrete strength performance at an early stage is also assured,” Correia says.
EnviroMix® is suitable for use in multiple concrete applications including readymix concrete, self-consolidating concrete, precast concrete and site batched concrete.
Correia says that on projects where the EnviroMix® technology has been deployed contractors have reported greater productivity. “Being able to meet the green materials specifications on a project and still keep to, or shorten, the construction schedule is a real advantage for contractors as this resulting in time and cost savings.”