FEATURE
Sealed
Deal
Watertight, self-sealing
concrete structures are
resilient for the long term
By Kim Biggar
Driving concrete piles in the construction of a deep
foundation makes them prone to cracking, which
leads to water penetration and corrosion of the rein-forcing
steel. This is an issue that pile driving contrac-tors
have dealt with largely by applying an oil-based coating
to the concrete piles before driving. The coating is intended
to serve as a barrier to water penetration.
The problem with this solution, says Alireza Biparva, a
concrete specialist at Kryton International Inc. in Vancouver,
B.C., is that some of the protective coating is almost certainly
damaged or stripped off the concrete during installation of
the pile. Friction with the soil during driving can damage the
membrane, reducing its effectiveness as a water barrier.
Once a concrete pile with uncoated areas is in direct con-tact
with soil, chemicals such as sulphates can corrode the
concrete, causing deterioration and weakening of the piles,
potentially leading to settlement of the structure they sup-port.
Use of a sulphate-resistant cement can help with this
issue, but it will not prevent water penetration.
Making concrete watertight
In 1973, Kryton International was launched with a new prod-uct
for concrete waterproofing. The Krystol® product (Krystol
T1) was originally created to be applied to the surface of con-crete.
Mixed with water, this powdered product is made into
a slurry that is applied using a concrete brush. The slurry
product is an effective solution both for the repair of exist-ing
structures and in new construction with precast piles. T1
not only acts as a physical barrier, it also penetrates the con-crete
to serve as chemical protection. Even if the coating or
the surface of the concrete is damaged, the concrete remains
protected because of the T1’s penetration into the concrete.
In the 1980s, Kryton invented Krystol Internal Membrane™
(KIM), a waterproofing admixture. KIM is added to the con-crete
as it is being made, rather than applied to hardened
concrete. Biparva, the research and development manager
for Kryton, describes this as an integral waterproofing system
that makes the concrete itself a water barrier.
PHOTOS COURTESY OF KRYTON INTERNATIONAL INC.
PILING CANADA 39