Under the contract, E & B is responsible for the HMA/SMA pavement for five years after all pavement is completed and open to unrestricted traffic. All mix placed on the project must be designed for 130,000,000 ESALs. E & B is responsible for establishing the Job Mix Formula (JMF) for the project, which must meet requirements of AASHTO M 323-04 for HMA or MP 8 for SMA; as well as selecting all materials to be used in the mix design.
During the warranty period, INDOT will monitor pavement performance and distress indicators — friction, International Roughness Index, longitudinal cracks, rut depth and transverse cracking — to evaluate whether or not corrective action is required by E & B to fulfill warranty obligations.
Corrective action for the following distress factors includes:
- Alligator cracks — Remove and replace distressed layer(s).
- Flushing — Remove and replace distressed area the full lane and depth.
- Longitudinal cracks — Repair by routing and sealing.
- Transverse cracks — Repair by routing and sealing.
- Longitudinal distortion — Remove and replace distressed layer(s).
- Potholes, slippage areas, raveling, segregation and other disintegrated areas — Remove and replace distressed layer(s).
- Rutting — Remove and replace distressed layers full lane width.
- Low friction — If average friction number is less than 35, remove and replace the distressed layers full lane width using originally specified SMA mix design.
Controlling quality of mix and pavement placement on this fast-track project has required a detailed quality control plan. The plan was put together to not only satisfy INDOT’s needs, but also insure consistent methodologies in the design and placement of the HMA and SMA pavements required for the project be used by the different E & B associates who would make up the two different operating shifts each day.
Starting at E & B’s Harding St., Indianapolis plant, where all HMA and SMA mixes were produced, procedures were put in place for handling the asphalt produced, including stockpiling of aggregate and RAP, storage of different grades of asphalt binder, operation of surge bins, application of anti-adhesive agents, loading trucks, and use of truck bed covers. Plant managers and operators also followed specific quality control measures for calibration the plant for each mixture produced, calibration the return of baghouse fines. Compaction of design specimens and determination of maximum specific gravity, conducting tests necessary to adjust and control the mixture at the plant, and maintaining control charts were outlined in the quality control plan. Mix properties at the plant and at the pavement site were monitored for asphalt content, aggregate gradation, temperatures, aggregate moisture, field compaction and surface smoothness. Samples from the pavement were obtained with plates and/or molds for each Quality Assurance mixture.
An Incat ignition oven was used to determine binder content in accordance with ITM 586. Pyrometer charts of the mixture temperatures at the plant were recorded each day of production, and mixture temperature at the paver was recorded behind the paver every two hours. Density was monitored and controlled using a Transtec PQI, and cores were taken and tested in accordance with AASHTO T166 and AASHTO T275. Pavement smoothness was checked using a profilagraph in accordance with ITM 901.
All mixes were sampled every 1,000 tons of mix placed and tested for air voids volumetrics and binder content.
Quality control measures for the paving and compaction operation were also implemented to facilitate a continuous placement of a quality mat. The paving train for the mainline paving operation consisted of a Roadtec SB 2500 material transfer vehicle, a Roadtec 190 paver, an Ingersoll-Rand DD-130 vibratory roller, an IR DD-110 vibratory roller and an IR DD-90 vibratory roller. The pavers used on the project were equipped with a feeder control system for an uninterrupted flow of material to the screed. The system not only controls the on-off action of the dual feed systems, but also the speed at which the feed systems operate.