Ready-to-use admixture reduces concrete cracking and curling

Cracks can weaken concrete, compromise its durability and allow ingress of corrosive elements such as water, chlorides and ice. Concrete applications such as floors, screed and precast panels with large surface-to-volume ratios have a higher risk of cracking.

Concrete cracking and curling is a result of shrinkage, which happens at all stages in the life of concrete, with a length of concrete cast potentially shrinking by as much as 0.08%. While concrete has excellent plasticity when fresh and high mechanical strength once set, it can only withstand minor deformation. When shrinkage comes up against a mechanical constraint, the concrete may crack.

Preventing concrete structures from cracking or curling is a top priority for contractors and manufacturers, to ensure the success of applications and to prevent cracking from spoiling the appearance of the concrete.

As a ready-to-use shrinkage-reducing admixture for concrete and mortars, CHRYSO asserts that its  Serenis product can reduce shrinkage by up to 80% depending on the conditions and concrete mix design. This makes it particularly suited for all applications requiring minimal shrinkage, including injection grouting, high and ultra-high performance concrete and special structures.

Evaporation takes place mainly from the surface of concrete, which leads to more shrinkage on the surface and as the concrete shrinks, the edges rise. The severity of this action depends on the surface-to-volume ratio but even the slightest curling is a risk. It can endanger an element’s integrity, leading to breakage during transport, unloading or even under its own weight. Reducing the amount of shrinkage reduces the possibility of curling.

Industrial floors made from concrete are normally divided into areas of 5 m x 5 m, bordered by shrinkage joints sawn into the surface of the concrete. CHRYSO’s Serenis is designed to allow users to increase the distance between shrinkage joints and more distance between shrinkage joints helps save time on laying floors, reduced maintenance costs and improved overall appearance.

The company explains that its admixture works by reducing the capillary tensions, therefore impacting the most important mechanism at the origin of shrinkage. It does not have a spreading effect and does not modify the water demand of concrete nor impact the water-to-cement ratio. It is compatible with new generation superplasticisers as well as traditional plasticisers and superplasticisers.