Due to their acoustic properties road surfaces with a fine and discontinuous grading curve as well as a void content of 8 to 16% are being built in Switzerland (semi porous asphalt mixture).
However, the knowledge of the variability of the volumetric and mechanical properties when producing such surfaces and the possible effects on the acoustic properties is missing largely. By means of systematic mechanical and acoustical investigations in the laboratory, during the laying process and after completion of 12 road surfaces, causes for the variability and their effect on the acoustical performance of noise reducing road surfaces will be identified. Guidelines for the road construction industry will be derived from the project results.
A list of road constructors will be evaluated, who offer low noise road surfaces as products. Three shall be invited to participate in the project. Per constructor one product shall be monitored for two years on two test sites (six sites in total). Documentation of geometrical and mechanical properties of the selected low noise products, e. g. void content, grading curve, binder content, ITSR, degree of compaction as well as the laying process. Execution of acoustic measurements on the test sites, e. g. CPX, texture, sound absorption, air flow resistance. Synthesis report on the variability of the acoustic properties of the selected asphalt pavements.
