Industry roundtable

"The ability to have a profiler run at various points in the asphalt production is also imperative. This can be owned or rented as needed. We should be profiling each course of the pavement before a top is placed to prevent reflective cracking from the lower course."

Collins, Pavement Technology: "The APA and APA Jr. are loaded wheel testers that are successfully being used to predict the rutting, fatigue, and moisture susceptibility characteristics of asphalt mixes in an environmentally controlled chamber wet or dry.

"One advantage the APA and APA Jr. offer contractors is they can perform two different types of rut testing (Rut Testing with Hoses and Hamburg Type Testing) and moisture testing.

"This equipment also has frequency drives which allow user to test mixes at multiple speeds and multiple rates of loading. This equipment also has controls to adjust the load. This is important as traffic volume and type may change during the warranty period."

Akehurst, Troxler Electronic Laboratories Inc.: "Much of the same equipment that is used today will still be required:

• Gilson shakers and sieves for determining the gradation of the coarse aggregate
• Ro-tap machine or other sieving device for determining the gradation of the fine aggregate
• Vacuum pump, flasks and other equipment needed to determine the specific gravity of the aggregates
• Gyratory Compactor to design HMA mixes and verify mixes being produced at plant meet requirements of mix design
• Equipment for determining the Gmb of test specimens
• Ignition ovens or Nuclear Asphalt Content Gauges for determining the asphalt content of the HMA material being produced
• Nuclear Density Gauge, non-nuclear density device or core drill for determining the in-place density of the HMA
• Profilograph or other device for determining the smoothness of the pavement."

Will contractors need to verify that mix performance and placement meets typical DOT warranty specifications, or are they simply liable for the pavement performance for the duration of the warranty period? Is the equipment limited to density and smoothness testing?
Apkarian, Transtech Systems Inc.: "If we are talking true warranty programs, the DOT should simply award the contract and allow the contractor to perform their duties. Most contractors know more than the DOTs about how to build and if they are willing to put up the bond for the project, the DOT should not be telling them how to do it.

"The contractor should be liable for the designated term of the warranty only. It's up to the contractor to verify anything if we want to talk about true warranty. Any reasonable contractor will indeed have a very rigorous QCQA plan when they approach these types of projects if nothing else then to protect their investment.

"This QCQA plan will be from start to finish and not be limited to density and smoothness. Density and smoothness may be two of the major factors the contractor needs to worry about or can use as a reference of overall performance, however there are many aspects that will factor into these two measures. We all know that if we achieve the targeted density and smoothness the road will last longer."

Collins, Pavement Technology: "Contractors will most likely be liable for the pavement performance for the duration of the warranty period. However, DOT's may include some parameters in the specification for mix performance and placement. The equipment is not limited to density and smoothness testing. Rut Testing will most likely be included."

Akehurst, Troxler Electronic Laboratories Inc.: "Contractors will need to meet basic applied performance criteria such as smoothness, rideability, lack of potholes, etc., as well as the laboratory performance measures that verify the mixes meet the design specifications. Longer term, where the applied performance may be adjusted over time, we suspect there will be increased requirements placed on the contractors to keep improving their product quality as well as the confidence level of the agencies."