Waterproof plaster for Vodacom Business Data Centre

A wide variety of products supplied by CHRYSO Southern Africa were used for the construction of a Vodacom Business Data Centre in Midrand. Designed to meet the increased demand for hosted services across the country, the data centre has been built in line with Vodacom’s green philosophy and is designed to have a minimal impact on the environment.

CHRYSO, together with Dave Tite from Concrete Testing services, gave technical support to Aveng Grinaker-LTA (the principal contractor for the Vodacom Business Data Centre) – particularly with regard to the waterproof plaster.

“The most common defect experienced by contractors on site is usually the plaster; therefore we focussed on creating a perfect plaster mix design. Vodacom requested a waterproof plaster in order to prevent the possibility of tiles falling off the façade due to water ingress. For consistency and quality purposes, Grinaker-LTA then elected to use waterproofed plaster for the entire building – in addition to the tile facades,” explains Rob Muirhead, Contracts Manager at Avenge Grinaker-LTA.

According to Muirhead, locating the correct sand for the plaster mix was vitally important. “After a few trials and a lot of research, it was decided to use washed, Vaal River sand. “The cleaner the sand, the better the plaster, the Vaal River sand contained less clay and had a sufficient amount of fines to assist in preventing plastic shrinkage cracks.”

The plaster was mechanically mixed to ensure the better dispersion of the CHRYSO admixtures and fibres as well as the sand. The following CHRYSO products were used:
• A CHRYSO®Plastisicer was part of the mix for all concrete work, including plasters and mortars. The admixture strongly disperses the fine particles in concrete to produce fluid, cohesive concrete with a low water-to-cement ratio
• CHRYSO®Mortar Plasticiser, a chloride-free admixture which entrains air to enhance durability, and improves cohesion and workability of the concrete mix. It makes the mix easy to plaster.
• CHRYSO®Fibre Plus was added to the mix used for plaster work to help reduce early age plastic shrinkage and settlement cracking. It also prevents the segregation of fine cement and sand particles which causes bleeding. By helping to reduce bleeding, there is more water available for the hydration process which improves bonding within the cement matrix. The product also improves the long-term durability and surface properties of the concrete
• CHRYSO®CIM helped in the bonding of the plaster to the wall surfaces. The bonding agent increases mortar plasticity, cohesion and adherence, and also improves tensile strength, abrasion resistance, and impact strength and acts as a curing aid.
• CHRYSO®Fuge B was used for the high standards of waterproofing specified by the client. The product blocks the pores in the plaster and ensures that mortar and concrete are highly resistant to capillary action. It virtually eliminates the infiltration of water under pressure.
• CHRYSO®Stab was used for enhancing the workability retentionof the plaster. The admixture has a built-in stabiliser that allows retardation of up to 8 hours, and also entrains air which imparts improved adhesion and easier placement of plaster.
• CHRYSO®Cure Acrylic water-based emulsion concrete curing compound was used by Aveng Grinaker-LTA to achieve economical, efficient plaster curing.
Muirhead praised the performance of the CHRYSO products used for the concrete mix and said that CHRYSO®Fibre Plus, in particular, had played an important role in the elimination of surface cracking. “CHRYSO®Fuge B helped us achieve the very high standards of waterproofing and the advice and input provided by Eddie Correia, CHRYSO SA’s Vice President and Dave Tite of Concrete Testing Services; who designed the concrete mix, were invaluable.”
The 3000 m2 energy-efficient Data Centre on Vodacom Boulevard houses virtual private servers, dedicated servers, managed hosting, and data back-up among its host of facilities, and a massive cooling plant.

“The professional team played a pivotal role in designing, co-ordinating and constructing a building that can fit the vast amount of mechanical and electrical work into a confined space but still make the building aesthetically pleasing,” concludes Muirhead.

Issued for Chryso SA, Jet Park / Further info: Kirsten Kelly, tel 011 395 9700 / www.chryso.com