Plant: 924 South Heald Street, Wilmington, DE 19801     Phone: (302) 655-1565     Fax: (302) 655-6331

                Office: 242 N. James St., Suite 102, Newport, DE 19804     Phone: (302) 658-6524     Fax: (302) 658-0684

Projects:

SR-1 Pave & Rehab Overlay




This section of highway was constructed in the late '80s with biodegradable concrete and was in dire need of repair. Biodegradable is layman’s terms for ASR, Alkali Silica Reactivity, a reaction between the aggregates and cement in Portland cement concrete resulting in no bond between the aggregate and the concrete.



DESIGN AND CRAFTSMANSHIP

The conventional solution would be a project designed with full depth replacement costing 10s of millions of dollars and restricting rush hour traffic to gridlock for at least two years. This would have been a bitter pill to swallow for both the State and the traveling public. This road had lasted less than one half of its design life and The Department already facing a severe funding short fall could not justify the cost of replacing the road. The average daily traffic on this road is nearly 50,000 vehicles shutting it down to a single lane would paralyze all commuters traveling to northern New Castle County from the south. A design had to be found that would not shut the road down and utilize the remaining structure of the existing road. This design was a multiple lift asphalt overlay constructed with night operations and opening the entire road to rush hour traffic everyday resulting in minimal impact to the traveling public and providing 10 to 15 years of service.



EXCELLENCE IN PROJECT TEAMWORK

The Department advertised this project through their Pave and Rehab program. This was the first time work on a limited access highway was attempted through The Department’s fast paced pave and rehab program. Diamond Materials was the successful bidder on bid day and the project team was established. Diamond Materials immediately met with The Departments representatives from pave and rehab management, materials and research, and traffic to jointly review various concerns and alternatives. Though mutual teamwork and the expertise of the individual entities concerns were addressed and changes were made lowering cost, increasing safety during construction, and improving the finished product. These included eliminating the full depth joint repairs by performing lower cost surface repairs, using less expensive materials for the shoulders, creating a resolution to reduce the speed limit in the construction zone where work had to be completed immediately adjacent to open lanes of traffic, profiling transitions at the bridge decks, and maintaining guide rail heights.



INNOVATION IN CONSTUCTION TECHNIQUES OR MATERIALS

The reaction that was causing the deterioration of the road was fueled by moisture. Through lobbying efforts by representatives from both Diamond Materials and Seim Products the State tried a revolutionary approach at dealing with the deteriorating concrete roadway. To slow the deterioration the first lift of the overlay was a product called ultra thin hot mix. This product requires a specialized paver that applies a polymer modified emulsion at an application rate 3 times that of a regular tack coat directly from the paver immediately before the ultra thin hot mix is placed sealing the pavement. This product is typically used as a wearing surface but was utilized a sealing layer for this project. The 1 ½” ultra thin layer was overlayed with a 2nd 2” 76-22 polymer hot mix. This 3 ½” section added structure to the pavement and should allow the overlay to bridge the joints of the underlying concrete pavement.



MEETING THE CHALLENGE OF A DIFFICULT JOB

The bid schedule of this project allowed 90 calendar days to complete, less than 3 months. Within this short time frame repairs had to be made to the existing concrete, the concrete had to be profile milled at numerous bridge approaches to allow smooth transition, over 130,000 square yards of ultra thin hot mix had to be placed, over 21,000 tons of 76-22 type c hot mix had to be placed, over 17 miles of rumble strips had to be cut into the pavement, in addition to various other items like pavement markings, top soiling, and seeding. All this work had to be completed at night with limited shifts that required at least 1 lane opened to traffic in each direct and all lanes of the entire road had to be opened to traffic each day. The project was a success and completed on schedule.



The project was completed for less than one tenth the cost of full depth replacement without ever impacting rush hour traffic. The new road rides much smoother than the original road and the new pavement markings have greater visibility making it safer at night and bad weather. The innovative approach of sealing the ASR concrete makes this project a model for numerous concrete roads with similar problems nationwide. All of the people involved with this project are very proud of the accomplishments that were achieved which serves as a testament to what dedication and teamwork can produce. The success of this project with the team from DELDOT has opened the door for more fast tracked projects to complete badly needed repairs to Delaware’s most heavily used roads making this project a true award winner.

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