Schon während des Bauprozesses erfassen Sensoren an den Maschinen den aktuellen Belagszustand und die Positionen von Fräsen oder Walzen.

Our Colleague: a Machine

Robot Road Construction 4.0 is the name of this project being sponsored by the German Federal Ministry of Transport and Digital Infrastructure in which STRABAG and its project partners are working together to test an autonomous system for asphalt paving.
Martin Muschalla
Martin Muschalla
Project Manager, TPA GmbH

On a testing site in Limburg on the Lahn, an asphalt paver starts up its engine. Six men and one woman carefully inspect more than 30 sensors and connections on the screed. The whole machine is covered in wires. Connectors and modules branch off and converge in a laptop in the driver’s cab of this impressive vehicle. Here you can watch a field trial with the automated asphalt paver.

There is a great demand for autonomous technologies in the field of road construction. “The place where the machine is now equipped with measurement technology is still occupied by a person today, standing in the line of traffic and exposed to fumes, noise and vibrations,” explains Sebastian Czaja, Project Engineer with TPA. In the future, the screed will work autonomously, so that no one will any longer have to work in the danger zone.

“You definitely feel uneasy”

Thomas Wagener, a trained road builder who has been working for STRABAG paving roads all over Germany for the past 22 years, would benefit from this new technology. As foreman, he supervises the paving process directly on the screed, checking paving width and layer thickness, monitoring the material mix – and constantly standing in the risk area between the paver and the highway. “You already have a queasy feeling when cars passing by at up to100 km/h just a few metres away,” he says, while excitedly watching the preparations for the test. In the future, machines will assist Wagener’s work by autonomously monitoring and controlling the processes. Road builders like Thomas Wagener would then become process controllers supervising the work of their “colleague machine” from the air-conditioned and safe cab.

Learning from mistakes

Ready to go: the wired paver applies the first steaming batch of hot asphalt onto the test section. The paving width and layer thickness are measured by the sensors, most of which originate from the project partners, who are currently all focusing on the process together. Among them is Alfons Horn, Vice President of Development of MOBA AG, a specialist in mobile automation solutions. “We are currently analysing the paver’s functioning during stopping and starting up phases to avoid any undesirable jolts or sudden movements. That’s important for obtaining a smooth surface”, Horn explains.

The sensors, which were mostly built by the project partners such as MOBA, collect data on paving width and layer thickness. The machine must be able to recognise specific details here as well, such as the paver’s behaviour during stopping and starting up phases to avoid jolts and sudden movements. That’s important for obtaining a smooth surface.

Torsten Schönbach, Group Leader at MOBA AG, is responsible for the Robot Road Construction 4.0 project for the technology group.
Running according to plan: Precise parameters were defined for the field trial in Limburg on the Lahn. This also ensures a smooth flow of the experiment.
TPA employee Sebastian Czaja is Project Engineer for the “Autonomous Machines in Road Construction 4.0” project.
The paver is equipped with more than 30 sensors to detect precisely defined processes at the screed.
Start of the field trial: After being loaded with asphalt, the paver begins its work along the test track.
Road construction employee Thomas Wagener measures the layer thickness of the asphalt during the test.
The asphalt is initially laid at a temperature of 120°C. The temperature is then changed to 160°C along the same surface. The purpose is to examine the reaction of the machine to the change of material.
The sensor systems are controlled by MOBA’s Chief Development Officer Alfons Horn.
Project Engineer Sebastian Czaja checks the temperature of the installed asphalt.
Sensors on the machines record the actual surface condition and the positions of the milling machines or rollers already during the construction process.
Asphalt reloading is an important part of the paving process. Interrupting the asphalt installation for reloading will result in a start-up hump. This situation is also simulated and recorded by the sensors in the field trial.
Project partner 3D-Mapping performs a laser scan on the test track before and after asphalt installation. In a model, the values are then compiled and used to evaluate the field trial.
For the laser scan, Christoph Weber, Development Egineer at 3D-Mapping, drives along the test track with a car specially developed for the measurement. Cameras are installed on the roof of the car to perform the scan.
The field trial is briefly interrupted for asphalt loading. The trial also examined the effect of stopping and starting in order to avoid so-called start-up bumps.
Thomas Wagener monitors the installation on the screed, checks the paving width and layer thickness, and examines the mix. In his professional life, he is constantly walking in the danger zone between the paver and the road.
Asphalt paving was carried out and monitored by sensors under different conditions along two test sections.

The “Autonomous Machines in Road Construction 4.0” project

The aim of the research project is the automation of asphalt paving to relieve the paving personnel through the connectivity of autonomous road construction machinery. The starting point is a 3D model with the target value of the road to be built. During the construction process, sensors on the machines record the actual paving status and determine the positions of the milling or rolling machines. These data converge in an information system that regulates and controls the working drives so there are no longer any deviations between the 3D setpoint model of the road and the measured actual positions of the milling drum, screed and roller. The use of these technical systems also ensures quality assurance during the paving process.

Connectivity within the entire process

Source: STRABAG brochure Robot 4.0

Everything under control – the sensors in Robot Road Construction 4.0:

Wire-rope sensors attached to the screed move out with the screed when it is extended to measure the width of the paved surface.

Sonic sensors are used on the side of the paver to determine the layer thickness. 

Infrared sensors measure the temperature of the asphalt.

Lidar sensors determine the distance between the machines using laser technology.  

Project partners:

  • TPA – Team “Process Stability
  • in Road Construction” (PSS)Technical University of Cologne, Cologne Laboratory for Construction Machines (KLB)
  • Technical University of Darmstadt, Highway Research Institute
  • 3D-Mapping Solutions GmbH, kinematic surveying of traffic networks
  • MOBA Mobile Automation AG, quality systems in mobile automation

Sponsored by:

Federal Ministry of Transport and Digital Infrastructure, represented by the Federal Highway Research Institute

Project sponsors: Federal Ministry of Transport and Digital Infrastructure, represented by the Federal Highway Research Institute Logos

Project schedule:

November 2017 – October 2020

“Experience alone
is not enough.”
Alfred Ulrich
Professor at the Institute for Construction and Agricultural Machinery at the Technical University of Cologne