A traditional sand and cement floor screed gets a boost in curing time with the addition of polypropylene screed fibres which helps to minimise shrinkage cracking. This is particularly useful when laying underfloor heating because it reduces the cracking that can occur over a period of time due to constant loads on the surface.

However, increasing the amount of fibre in a mix results in it becoming stiffer and harder to work which is a drawback, but one that is heavily outweighed by the benefits. These are that the fibres will increase tensile strength, reduce shrinkage and cracking, help to prevent thermal shock and give good resistance to impact or abrasion.

The Science Behind Screed Fibres: Enhancing Strength and Durability

The use of recycled aggregates in the production of a concrete or screed mix has also been gaining popularity as it helps to promote sustainability. This is especially true with FRCC mixes, where recycled aggregates are mixed with sand to form a mixture that can be used as a base layer for flooring or a finish for construction work. Unfortunately, the aging behavior of such mixes is not well known and their performance in terms of strength or durability is not always warranted.

This research aimed to assess the durability of a FRCC with 40% recycled aggregates and to compare it to a standard mix. For this, the sand-cement mortar was fabricated using Portland cement of type CEM II/A LL 42.5 R CP2 CE NF and dry powdered plant fibers (hemp, flax, miscanthus) with different lengths. The effects of the changes in the water dosage and the fibre content on the hydration process of the cement, the permeability, and the strength of the screed were studied.