DuPont Elastomers Pontchartrain site in LaPlace, LA is a chemical plant that produces many products essential to the auto industry and production of plastics. The plant produces pigments for paints, polystyrenes and several types of plastics used to make everyday household items. This project involved the 14,000-square-foot secondary containment area known as the 1192 pad that was coated with a fiber reinforced epoxy novalac coating system. Upon reviewing the site, Structural Preservation Systems (SPS) noted that the coating system was experiencing widespread failure and was peeling up in large sheets originating from the expansion joints. SPS was able to obtain basic information and a drawing of the area but needed to understand why the coating was failing. After consulting with the Engineering Services division of SPS, the team decided the best step for the owner would be to conduct a condition survey to understand the chemical and physical characteristics of the coating system failure and then present the findings and recommended repair process to the owner. The survey revealed that there was a failure between the primer and base coat of the existing coating and the chemicals in the area were eating the coating from underneath. Based on this discovery, SPS determined that the entire system would need to be removed and a new coating system installed. After reviewing the condition survey findings and repair strategy, the owner selected SPS to remove and replace the existing coating system.

The project began with the removal of the existing failed coating with handheld pneumatic tools, electric scarifiers, and scabblers. The failed expansion joint material was removed in its entirety and cracks were routed out to ensure a long lasting crack repair. Next, crews abrasive blasted the concrete to remove any embedded containments and open the concrete pore structure to enhance the mechanical bond of the new material to the existing concrete. Expansion joints received the same preparation as the concrete slab with additional grinding of the shoulders of the joints to remove adhered material. The team performed the appropriate tests to ensure the concrete did not contain an excessive amount of moisture, was the correct temperature and that the substrate had the correct bond strength to accept the new coating. The contours of the concrete slab were reestablished by filling any voids or honeycombs in the existing concrete with an epoxy scratch coat. Crews installed coves at all horizontal and vertical interfaces in an attempt to prevent coating failure and cracks at those locations. To aid the bonding of the new coating, an epoxy primer was applied to the prepared substrate. Next, a thick basecoat of 1/16-inch was applied using a plasterer's trowel. Before the basecoat began to cure, crews pressed one layer of one-ounce chopped strand fiber into the wet basecoat. The fiber mat was pressed in using a stiff bristle brush and was saturated with the basecoat resin only with no aggregate. SPS' crews immediately rolled the fiber with a rib roller to remove any air pockets beneath the fiber mat. Once the basecoat had cured, a topcoat with 15-20 mils thickness was applied and a slip-resistant aggregate was placed into the wet topcoat. When the topcoat had cured, excess aggregate was swept off and a sealer coat was installed. New expansion joints were installed using backer rod and polysulfide sealant.

DuPont was extremely impressed by the condition survey process and SPS' presentation to the client explained key points and data. SPS completed the first phase of repairs in January 2009 and finished repairs for the second half of the containment area in the spring.