Below-Grade

Homeplus Hypermarkets
Korea

BACKGROUND
The hypermarket – a very large retail store offering groceries, dry goods, home furnishings and more – is one of the fastest-growing retail trends in Europe and Asia. Naturally, a store of this size requires a sizeable parking facility. And since hypermarkets are often located in areas where real estate is at a premium, many owners and builders utilize the rooftops of these structures as parking lots.

When building a new Homeplus Hypermarket in Dongdaemun, Korea, Samsung Construction was in search of a waterproofing solution for the rooftop parking lot. They had utilized a number of different waterproofing systems including rubberized asphalt, polyurethane coatings and various membranes, in past projects, but had experienced challenges with cracking, air pockets, fractures and peeling.

Since rooftop parking lots are expensive to repair and difficult and inconvenient to take out of service, Samsung Construction needed a more reliable and permanent waterproofing option than had previously been used.

SOLUTION
Buil Keonwha Co., Ltd., Kryton’s Korean dealer, recommended the Krystol Internal Membrane™ (KIM™) admixture. KIM uses Kryton’s proprietary crystalline technology to transform concrete into a watertight barrier. When added to a concrete mix, Krystol™ reacts with water and unhydrated concrete, causing millions of needle-like crystals to form, blocking the penetration of water and corrosive elements. Over time, incoming water causes additional crystals to form, self-sealing small cracks and saving repair and maintenance time and costs.

Because KIM had never before been used in this type of project in Korea, Buil Keonwha faced many questions from the project’s architect, supervisor and contractors. After viewing a successful demonstration, however, the Samsung Construction project team chose to use KIM in place of an external membrane system.

To avoid shrinkage cracks, the 4,600km2, 15-20 cm thick slab was poured in two phases, 15 days apart. The joint between pours was treated with Krystol Waterstop slurry for added protection. Although cracks greater than .5mm appeared in the rooftop parking lot at the Dongdaemun Homeplus Hypermarket, they self-healed. There was no water penetration and the roof remains leak-free.

Pleased with KIM’s performance and the time and cost savings it generated for the Dongdaemun project, Samsung Construction began using the Krystol system in other Homeplus Hypermarket projects. To date, KIM, Krystol T1/T2 and the Krystol Waterstop System have been used in the rooftop parking lots of eleven Homeplus Hypermarkets, including:

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Samsung Tesco's first HomePlus Hypermarket store under construction in Seoul.

The first phase of the 4600m2 concrete pour.

The KIMT concrete experienced less shrinkage and less cracking during the curing period.