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When Yates' paving crew took over and began placing asphalt, the Trimble PCS400 allowed them to further fine tune the slope requirements and ultimately deliver a warranty project not many contractors would consider.

Located at Dames Point, a highly sensitive protected area for wildlife on the St. John's River, the project had environmental concerns as well as tight tolerance issues. And, the work had to be completed by the end of 2008 in order to begin receiving cargo ships in January.

Ready to pave

After International Underground completed grading the sandy base and before crews could begin placing asphalt, the entire site was covered with a geo-grid material and a new stabilized aggregate base developed by Yates and called Easy Base Plus, which is comprised of limestone aggregate and (boiler) flash material from a nearby power plant.

Once the aggregate, flash and water are mixed in a pug mill and placed in two 4-inch lifts over the geo-grid material, it forms a hard concrete-like base ready for asphalt. The project called for seven inches of asphalt - three inches of 19mm base course mix, two inches of 12.5mm binder course mix and two inches of 12.5mm surface course mix, with a polymer additive used in areas subjected to heavy cranes used to transfer containers.

The reason grade work was so important to the success of the paving operation is because of the difficulty in maintaining a one percent cross slope in the final laydown of the asphalt. One percent equates to a one foot drop across a 100 foot wide surface, whereas a two percent slope (commonly used on highway paving projects from centerline to the shoulder) equates to a two foot drop across a 100 foot wide surface.