FGSV Colloquium // InLine Pave® Rooted in the German Catalogue of Construction Methods
Part 4: InLine Pave® – Simply the Better Alternative for Planning, Construction and Use
Every Step in the Process is Better
Constructing and rehabilitating roads are complex processes. Planning engineers, contracting authorities and contractors always have to balance the technically feasible solutions against the costs, environmental factors and quality. The method selected influences the speed at which the road project advances, its cost-efficiency, the road’s service properties and, last but not least, its sustainability.
Lars Keller has already carried out numerous projects using the InLine Pave® technique developed by VÖGELE. He spoke with RoadNews about his experience of the paving process from the vantage of a contractor with a constant eye on both the quality of his work and its cost-efficiency.
“One method – unlimited possibilities.”
Managing Director of F. Winkler KG,
Lars Keller is head of working party 7.4 “Construction technology” of the Road and Transportation Research Association (FGSV). Here is his report of his practical experience of building compact asphalt pavements.
RoadNews: Mr Keller, you are familiar with compact asphalt pavements from your everyday work and have already planned and carried out several projects. How do you rate InLine Pave® on the basis of your experience?
Lars Keller: Of all the various technical solutions available for building compact asphalt pavements, InLine Pave® is by far the best. This method offers organizational, economic and technical advantages.
RoadNews: As a businessman, you have to work cost-efficiently. What do you consider to be the most important economic advantage of InLine Pave®?
Lars Keller: It lies in the high level of machine utilization, for every contractor can use InLine Pave® machinery from VÖGELE for conventional paving work, too. In other words, investing in this technology does not mean concentrating exclusively on the building of compact asphalt pavements. That is very important.
RoadNews: Which properties of the InLine Pave® process developed by VÖGELE do you consider to be important when planning and organizing projects with this technology?
Lars Keller: The ease with which these slightly modified standard machines can be transported is a great advantage. They measure 3.1m in height and 3m in width for transport – with these standard dimensions they can be transported in exactly the same way as any other paver. Another aspect that should not be underestimated is the short time needed to set up the pavers on site. This makes it much easier to plan InLine Pave® jobs.
RoadNews: Let us turn to the paving process itself: what are the main technical advantages here?
Lars Keller: The high degree of compaction is clearly an advantage. Extremely good precompaction of the bottom layer means that it does not have to be compacted through the wearing course. This minimizes the risk of the wearing course being mixed with the layer underneath. The decrease in subsequent compaction by rolling also significantly reduces the risk of irregularities.
RoadNews: You say that compaction of the bottom layer – that will usually be the binder course – is excellent. Have you measured this?
Lars Keller: Yes. We have consistently measured densities between 97 and 99% behind the AB 600 High Compaction Screed in TP2 Plus version. These results also show that a very high level of precompaction is achieved throughout the entire layer thickness. One of the reasons for this lies in the high compaction of the binder course, which contains a relatively small amount of binder. The comparatively thin wearing course with more bitumen is then precompacted by the paver and subsequently compacted to its final density by rollers.
RoadNews: Speaking of rollers – how many and which rollers do you use for final compaction of the asphalt layers?
Lars Keller: Only a few rollers are needed, for it is only the thin wearing course that needs final compaction by rolling. Very good results are obtained using the oscillation rollers built by HAMM. These dynamic compactors are highly efficient, even on thin pavements and do not displace the material.
In rehabilitation projects and when paving “hot to cold”, they also yield yet another advantage: oscillation prevents damage to the cold roadway at the joint between old and new asphalt pavement. As a result, high quality is always assured and the existing pavement is not damaged when rehabilitating other areas.
RoadNews: Evenness is a point that immediately comes to mind when speaking of “quality”. It influences the road’s service properties and sustainability. What can you tell us about the evenness of asphalt pavements built with InLine Pave®?
Lars Keller: It’s all good news. Each of the two pavers achieves excellent evenness through its self-levelling property. Minor irregularities in the base are largely eliminated by the paver for the binder course and the rest is levelled out by the paver for the wearing course. The paver operator doesn’t need to lift a finger. A 5cm irregularity under the binder course is reduced to just 2mm on the wearing course – ideal conditions for a perfectly level pavement. This has been confirmed in all projects to date.
RoadNews: Sounds like you have already placed a variety of materials using the InLine Pave® method. For what kind of projects have you used this method?
Lars Keller: We have used it for projects of various sizes and for roads of different construction classes. We have combined binder course and wearing course, as well as wearing course and base course. We have even built roads with ZWOPA, the two-layer porous asphalt, using InLine Pave®. My experience has shown that the method works on motorways, trunk roads, county roads and urban roads above a certain minimum size. In my opinion, this technology is cost-efficient for lot sizes from 10,000m² upwards.
RoadNews: After so many projects, have you come across any special features to be taken into account when working with an InLine Pave® train?
Lars Keller: No, just some noteworthy opportunities, such as paving asphalt on bridge decks. Jobs like this can be integrated into the process superbly with InLine Pave®: the paver for the binder course simply stops before the bridge, while the other paver continues working. The paver for the binder course then restarts after the bridge, as in a conventional project. That is only possible with InLine Pave®.
RoadNews: One last question concerning paver operation. VÖGELE’s operating concept ErgoPlus® is well known for its user-friendliness. Is that also true of the InLine Pave® machines?
Lars Keller: Most definitely. The pavers’ operation is virtually no different from that of a conventional paver. The operators do not need any lengthy training. This also makes InLine Pave® financially attractive for smaller firms. A great deal of slumbering potential can be exploited here with a clever team and well organized logistics.