clients & projects

In 2010 the Port Authority of New York closed one of the busiest runways at John F. Kennedy International Airport (JFK) from March 1 to June 27 for a complete repaving. The existing asphalt surface on the runway was deteriorating, creating the need for frequent repairs, which led in turn to costly delays to airport operations. As a result, the Port Authority decided to repave the runway with a longer lasting, customized concrete.

CTLGroup joined the team of contractors responsible for paving 220,000 cubic yards of concrete and readying the new 14,572-foot runway for traffic in less than four months. The project, which was estimated to save $500 million long-term and decrease flight delays by 10,500 hours per year if successful, left no margin for error in time management, quality or efficiency. CTLGroup played a key role in the design, testing and batching of the concrete to ensure the best and longest lasting workability. In the end, the project’s objectives were completed ahead of schedule; earning the primary contractor a $5 million bonus, and allowing the client to reopen the runway early.

The first major challenge the project presented was the need for a special concrete mixture design. The concrete had to meet exceptionally high standards of quality while maintaining good workability to keep the paving process on a tight schedule. CTLGroup assisted with the mixture design, identifying compatible materials by evaluating the interaction of slag, fly ash, different cements, water reducers and superplasticizers. This information was used to identify the combination that would provide the best workability and optimal concrete placement characteristics under anticipated paving conditions. The final product was a very unique gap-graded mix that was over 40 percent slag with aggregate measuring up to 2.5 inches.

Once the optimum combinations for the mixture design were identified, CTLGroup determined the equivalent admixture dosages from a variety of admixture suppliers to enable the contractor to utilize admixture quantities in selecting the best performing and most economical concrete mix. CTLGroup assisted the aggregate suppliers as well, providing materials testing for the pre-approval of the aggregates.

CTLGroup provided consulting and testing services from the start of the project to its conclusion, including alkali-silica reactivity testing to ensure a satisfactory slag/cement combination and long term performance. Additionally, the firm provided assistance during the batching process to ensure consistency throughout. This allowed us to facilitate the project’s successful completion ahead of schedule.