25 January 2021

Hot and windy conditions can lead to plastic shrinkage cracking on fresh concrete, but CHRYSO® ProFilm 19 can solve this problem, without the addition of extra water to the concrete mix.

One of the dangers of working in low humidity conditions – even inside heated buildings during cold weather – is the rapid evaporation of surface moisture from the concrete. This can cause map cracking and plastic shrinkage, where cracks can penetrate to the full depth of a concrete slab.

According to the American Concrete Institute (ACI), plastic shrinkage cracking of concrete is likely to occur whenever the evaporation rate is more than 1 kg per square metre per hour. The ACI highlights that this rate of evaporation can be readily caused by many combinations of air temperature, relative humidity, concrete temperature and wind velocity.

As an evaporation reducer, CHRYSO® ProFilm 19 prevents this cracking by protecting fresh concrete from the effects of excessive moisture loss in rapid drying conditions. Furthermore, it can achieve this result without increasing the bleed. By spraying this evaporation-reducing product onto fresh concrete surfaces, the user creates a continuous mono-molecular film over the concrete, which inhibits the rapid loss of bleed water.

This film lasts as long as the concrete remains plastic, even where floating and trowelling operations must be conducted to create the required surface finish. CHRYSO® ProFilm 19 is a water based product which is compliant with guidelines on volatile organic compounds (VOCs).

The effectiveness of the mono-molecular film means that there is no need for water spraying on the surface of the concrete in order to slow the evaporation process. It can be used on a range of horizontal concrete pours where the evaporation rate may exceed the bleeding rate of concrete. These applications include industrial floors, roads, bridge decks, slabs, patios, driveways and sidewalks.

CHRYSO® ProFilm 19 is ideal in concrete applications that produce little or no bleed water, such as mixes with low water content.

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