A trial undertaken at a new COVID-19 hospital that is being constructed in Gauteng has shown that Spray-Lock Concrete Protection’s SCP technology is able to significantly reduce the moisture content in concrete in an extremely short timeframe. This enables faster installation of the floor coverings on the subfloors by flooring contractors to help ensure timely completion of a project.

The project chose a Caisson VI-D4 moisture meter to measure concrete surface moisture before installing flooring materials. SCP 327 reduced the moisture content substantially in a mock floor slab to less than 3% within 14 days from concrete placement. This would have only been possible within 21 to 28 days, or more from the placement of the concrete using conventional moisture barrier products. Clinton Yung Fah, Chief Executive Officer of H&M Flooring, the vinyl flooring contractor, says that he is satisfied with the overall performance of the product.

The company has built a solid reputation over the years for the high quality of its flooring installations. This stellar performance is based on the company’s mantra, namely “do it right, first time”. It was, therefore, appointed to install the vinyl covering on the subfloors for the new COVID-19 hospital. Conventionally, the company will install up to 8mm or two layers of self-levelling for vinyl floors. On this project, however, the vinyl coverings average between 3mm and 5mm in thickness.

H&M Flooring works closely with the main contractor on all its projects to ensure that the subfloors are of the required specification before it installs its floor coverings. This approach has ensured a successful outcome on all its large flooring projects throughout the country.

The trial was undertaken by SprayLock Africa, Spray-Lock Concrete Protection’s African distributor, and Concrete Junction, an approved applicator of the technology, on behalf of Enza Construction, which is building the new 500-bed hospital.

RCR Floors, which was appointed to construct the subfloors for the new COVID-19 hospital, placed the 36m² sample concrete slab and H&M Flooring measured the moisture content before and after placing the topping.

The tests were supervised by Sheldon White, a SprayLock Africa Technical Engineer, and Leonard Scott-Turner, owner of Concrete Junction, throughout the trial period.

White says that SCP solutions, based on cutting-edge colloidal silica technology, react with available alkalis to close bleed water channels and capillaries with reaction products.

“This action holds moisture in the concrete to facilitate curing. The surface of the concrete can achieve a ‘dry’ condition and receive adhesives and flooring while the concrete’s internal

structure is kept at a high level of moisture conducive to continued curing. Water and water vapour transport mechanisms are significantly affected. This allows the surface of the

concrete to act independently of the total slab moisture content. In this way, SCP products serve as an excellent method of curing concrete while providing a slab surface that can receive resilient flooring, adhesives and coatings in as little as 14 days,” White says.

As demonstrated by the test, there was a constant reduction in the moisture content since SCP 327 was applied on the sample concrete slab by SprayLock Africa on 23 July 2020 at 06h30.

By 28 July 2020, moisture content stood at 4,9% and, two days later, 4,4%. Exactly 13 days from the application of SCP 327 and 14 days from the concrete placement on 4 August 2020, the moisture content was 3,4%.

H&M Flooring then applied its self-levelling topping on the concrete floor slab.  Moisture tests conducted by the company on 5 August 2020 provided readings of between 2,1% and 2,3% on the topping.

The surrounding concrete area where SCP 327 was applied was also tested, with moisture content readings varying between 2,2% and 2,4% on the concrete surface.

Carl White, Managing Director of SprayLock Africa, says that this is just another example of how SCP continues to outperform conventional membrane-forming curing compounds, as well as water ponding, or water-saturated coverings.

“Membrane-forming curing compounds were developed as a response to the need for a time-saving alternative to water ponding. While they are widely recognised as providing ‘adequate’ curing, they are not considered as effective as water ponding or water-saturated coverings. Membranes and water ponding are also temporary, whereas SCP products become a permanent part of the concrete. The objective of curing is to enable concrete to meet performance parameters. SCP products produce those performance parameters at a rate equal to or better than moist curing,” White concludes.