It has been stated by our competitors which utilise EPS in their formwork that “XPS insulation cannot be used for Insulating Concrete Formwork, because it doesn’t allow the concrete to dry”. Anyone that knows anything about concrete will know instantly this statement is untrue because CONCRETE CURES, IT DOES NOT DRY! Hence why concrete can set under water!
R-Wall uses the higher grade insulation XPS. XPS is closed cell which prevents ingress of water. EPS is open cell which allows water to move through the voids. The difference can be seen in the image at 25x zoom under a microscope.
R-Walls XPS is in fact advantageous to the curing process of Concrete by helping to keep the concrete moist. Concrete hardens as a result of a chemical reaction, called hydration, between cement and water, not because it dries. The hardening or curing as it is called, continues as long as moisture remains in the concrete. If too much water is lost from the concrete, the hardening process slows down or ceases. Therefore the concrete continues to gain strength after pouring, for as long as it retains its moisture.
It has been determined that, moist curing concrete for 20 days or more can double the concretes strength, compared to 4 days of moist curing, which is considered a minimum. Concrete that dries too rapidly and doesn’t retain its moisture can reach less than half of its potential design strength and results in a greater number of cracks.
R-Wall creates an ideal environment for the hydration of concrete in two ways;
1. Uses XPS - closed cell insulation which prevents the ingress of water into the board. This maintains the moisture in the concrete, increasing the length of the hydration process and therefore the strength of the concrete.
2. The insulated formwork sandwiches the concrete and creates an ideal environment protecting the hydration process from external weather temperatures (too cold and the concrete hydration can cease, too hot and moisture is lost and hydration too rapid resulting in weakened concrete)
R-Wall is therefore the optimum choice for Insulated Concrete Formwork!
Build stronger, build better, build R-Wall! 👍