Design and Construction Factors Affecting Initial Roughness of Asphalt Pavement in Wisconsin

Past studies have shown that the initial pavement roughness greatly affects future pavement roughness and roughness progression rate. Initial pavement roughness is also an important input to the roughness prediction model in mechanistic-empirical (M-E) design guide. This study analyzed the design and construction factors affecting the initial roughness of asphalt-surfaced pavements. Initial International Roughness Index (IRI) of 442 asphalt-surfaced pavements constructed from 2000 to 2004 were analyzed using analysis of covariates. The factors considered in this study included hot mix asphalt (HMA) layer thickness, project location (urban vs. rural), base type, pavement classification, and pavement length. The factors affecting initial pavement roughness were identified and discussed.