Construction of the $215-million Richland Creek Reservoir Water Supply Program for Paulding County, Georgia began in 2015. Paulding County engaged program manager Brown and Caldwell, design firm Arcadis and three construction companies, including Vermont-based PC Construction, the construction manager at risk (CMAR) for the water treatment plant (WTP) and intake pumping stations.
Arcadis had recently used Xypex Admix C-500 crystalline water-proofing technology in a wastewater project in Birmingham, Alabama.
“They recognized the value Xypex delivers and decided to use it for Richland Creek,” notes Paul Derby, a Xypex technical consultant for the southeast U.S. region. “The addition of Xypex Admix to the concrete used in the water-holding structures at the WTP means that other waterproofing and protection coatings or costly epoxy crack injection could be eliminated, saving time and money.”
Xypex Admix C-500 is added to the concrete at batching and consists of Portland cement, silica sand, and active, proprietary chemicals that react with the moisture and by-products of cement hydration to cause a catalytic reaction that results in the formation of non-soluble crystals that fill the natural pores and capillary tracts in concrete. This crystalline formation prevents the penetration of water and other liquids.
Xypex Admix C-500 becomes a permanent and integral part of the concrete structure and continues to prevent the ingress of water and other liquids for the life of the structure. Admix C-500 can also heal hairline cracks up to 0.4 mm while providing chemical resistance properties that mitigate the attack of chlorides and sulfates and the effects of carbonation and alkali-aggregate reaction.
Arcadis specified that Xypex Admix be added to the ready-mix at a dosage rate of 3 per cent by weight of cement.
“Xypex Admix is typically used at 2 to 3 per cent by weight of cement,” Derby says. “Arcadis wanted the higher dosage rate to ensure maximum protection against the chemicals that would be used in the water treatment process, and to protect the concrete and the reinforcing steel within it.”
About 6,000 cubic yards of concrete used throughout the project were treated with Xypex Admix.
One of the first structures poured was the 40-foot diameter gravity thickener tank, using 200 cubic yards of ready mix concrete treated with Xypex Admix. The tank was then filled with clean water to leak test it. Within a few days, seepage was seen on the outside of the tank through thin cracks.
On most jobs, PC Construction would have begun crack injection. Here, the tank was allowed to continue leaking to enable the active chemicals in Xypex Admix to react with the moisture and the by-products of cement hydration to enable the catalytic reaction to generate non-soluble crystals that gradually sealed the leaks.
“By using Xypex Admix for all water-holding structures, any leaks we experienced healed themselves,” says Dan Nawrocki, vice president for PC Construction. “Xypex costs a little more up front, but it is an investment in quality.”
PC Construction project manager, Joe DeHart, had little prior experience with Xypex. “I never thought it could be a total solution,” he says. “It’s a rare case when you pour a large water holding structure and you don’t have any leaks. As we do more and more design-build and CMAR projects, we have opportunities to specify Xypex during the design process. Those are situations where we can help the owner realize a better final product with long-term benefits while eliminating uncertainty.”
This content is sponsored by Xypex in collaboration with ConstructConnect® Media. To learn more about Xypex, visit www.xypex.com.