Great information on the two web links. It describes nearly everything the whole asphalt world is discussing about and it’s interesting to see, that we have worldwide more or less the same problems, and that there is still a lot to do to improve the asphalt laying process and of course the complete asphalt process chain. For example remixing is also a big subject in Europe at the moment. In Germany we will have a new regulation for asphalt trucks. Beginning of 2015 the use of temperature-controlled asphalt trucks is required for highways and main roads. By the year 2019 this regulation is valid for all asphalt roads. Another example or investigation made during the PAST research project is the asphalt loading process onto trucks at asphalt plants. Here improvements has been made in respect to avoid steep material cones, which normally also causes material segregation.

At the moment asphalt specialists in Europe think about a way to refine the asphalt surface. The idea here is to start a research project and analyze and develope the special tooling necessary for the laying process, as well as the advanced material used to increase the longevity of the road.

For temperature controlled asphalt trucks see:

http://www.transp­ort-online.de/Transport-N­ews/Fahrzeug-Technik/1338­7/Asphalttransporte-Kompl­ett-isoliert­

The interview with Tom Scullion of TTI about thermal segregation fits well to the paving quality discussion How to prevent pavement failure?

Valid points that it is difficult to improve if you don't measure temperature or compaction besides the point that you cannot correct anymore if the asphalt is laid down and rolled. A lot of problems,however, already start earlier, at the asphalt plant, for example. The quality of asphalt plays a major role, what additives are used, when they are added to the drum, how they are mixed, how asphalt gets loaded onto transport vehicles and .....This is a good blog post about what to look out for in material mixes and transport.

Considering the asphalt quality measurement methods used normally today, we only find a few methodical approaches, which continuously test the asphalt laying process. For example temperature measurement behind the paver and compaction measurement on rollers. However to really improve the asphalt quality situation, we have to implement much more quality measurement systems, which continuously measures the road quality over the complete production chain, like every production fabric does. This includes in particular asphalt thickness measurement, temperature measurement for the entire process chain, evenness measurement, surface structure measurement, compaction measurement for the underground as well as for the asphalt.

Without these specific measurement systems nobody can guarantee the asphalt laying quality. In particular, if we intend to install feedback loops in order to even more optimize the laying process, measurement systems are essential. Of course additional costs for quality measurement systems cannot be neglected, but they will play a minor role considering the total investments for roads.

So for improving and measuring success, we need these additional measurement systems (continously working) as well as pavement management and training for the complete production chain.
Implementing all of these continously and in real time working measurment systems into the whole process chain is still a challenge today.

To answer the questions and underline the importance of the question, maybe we should first consider the production costs of roads again. For highways we have a bandwidth from 1 Mio €/km up to 10 Mio€/km depending on the road size, the underground condition, design specialties … If we have to repair only the top layer, we must invest about 25.000€/km and repairing asphalt and underground together this costs about 200.000€/km. The above mentioned costs should only demonstrate, that we talk about a very expensive product, which is obvious. If we consider other expensive products like cars, mobile machines, electronic components… which are produced in a fabric, it’s state of the art, that these products run through a lot of quality measurement systems (sometimes there are thousands of different measurement steps), which are continuously applied during the whole production cycle. Without such quality assurance systems nobody can guarantee an adequate product quality, and as a consequence nobody would like to give his own money for that.