New Approaches to Quality Control in Road Construction – QUAST

Due to on-site production in varying environmental and meteorological conditions and decentralised material supply, there are significantly greater quality fluctuations in road construction than in the sector of industrial production. During road construction, complicated tasks that cannot always be precisely planned have to be mastered. The stabilisation of the process and thus the easing of the burden on the construction site represents an enormous challenge. This challenge was to be dealt with in the project “New Approaches to Quality Monitoring in Road Construction (QUAST)”.

The aim of the project was to cut quality-reducing paving weak points in the construction of transportation infrastructures by comprehensively monitoring the quality of the relevant surface parameters such as paving width, thickness, cross profile, flatness and degree of compaction.

The quality should not be monitored only after the paving process has been completed, but by a new approach during the building process. Here, new measuring procedures and sensor technologies should be implemented so that data on the “finished layer“ can be delivered during the last roller pass. The data determined during the final roller pass should recognize control deviations of the relevant coating parameters in order to transmit potential corrections to the paver and the other rolls. This enables targeted corrections to be made during the paving process in real-time at one or, if necessary, several points simultaneously in the asphalt paving in the event of impermissible deviations. Over the course of the project, several field tests were carried out to examine the new quality monitoring system. This made it possible to calibrate current developments on the machines (pavers and rollers) and to adapt them to the real installation conditions at any time. The early-stage tests were of great importance, since this also allowed the laser system for height distance measurement to be tested, which provided, regarding the longitudinal flatness and the layer thickness determination, an important basis for both the QUAST project and the parties involved.

During the project, measurement, information and communication sensors were developed that made it possible to record the ACTUAL condition — based on relevant surface parameters — of the installed road surface and to compare it with the TARGET value specifications, to be able to intervene if deviations made it necessary.

At the end of the project, the demonstrator machines used in the project (BOMAG paver and BOMAG roller) were equipped with the developed measuring systems and control concepts and demonstrated to the specialist public at a closing event on the test site of project partner MOBA Mobile Automation AG in Limburg an der Lahn.

The results’ added value should be new measuring methods for quality control during the paving process. With a successful review of the results in relation to their suitability for practical use, existing rollers across the group could be retrofitted with these measuring systems.

The results of the project flow into the current research project “Robot Road Construction 4.0” (see project presentation — Colleague Machine).