Relationship between road surface macrotexture characteristics and CPX noise of a bituminous gap-graded mixture

The aim of this study is to characterize the surface behavior (on an acoustical and a textural level) of bituminous mixtures. The relationship between a road surface characteristic (MPD) and close proxim- ity noise of a bituminous mixture has been analyzed. The survey was conducted by the Laboratory of Acoustic Applied to Civil Engineering (LA2IC) on a test track with two experimental sections paved with ultrathin gap-graded mixtures, with di􏰜erent air void content. Acoustic 􏰝eld measurements of the tire/pavement interaction in close proximity to the contact patch were carried out with a trailer with a protective chamber (TiresonicMk4-LA2IC). Also, measurements of super􏰝cial macrotexture pro􏰝le have been performed with the LaserDynamicPG-LA2IC in order to understand the in􏰞uence of texture on sound generation of the analyzed bituminous mixtures. In this communication it is shown that the macrotexture pro􏰝le of these ultrathin gap-graded pavements has a strong in􏰞uence on the sound generation at intermediate frequencies. Furthermore, it is demonstrated that the commonly accepted belief, that road surfaces with high porosity emit less sound levels, is not always ful􏰝lled.