This report documents observation of a construction project west of Nashville, Tennessee that did not use a tack coat during the placement of the hot mix asphalt (HMA). This observation took place on June 23, 1998. For this project, the existing pavement was milled approximately 50 mm (2 in) with the majority of the millings being used as recycled asphalt pavement (RAP) within the mixture being produced. Instead of sweeping the milled portion clean, the contractor lightly swept the milled surface, leaving a small amount of millings primarily in the bottom of the grooves. The new HMA mixture was then placed directly onto the milled surface with no tack coat. The premise of this methodology was that the grooved pavement in conjunction with the melting of the asphalt within the loose millings by the heat of the placed mixture would result in a bond between the placed mixture and underlying pavement, and a tack coat was not needed. Photos. 10p.
The Novachip process, also known as ultrathin friction course, was developed in France in 1986. The process utilizes a single piece of equipment to pl...
Thin-lift hot mix asphalt (HMA) layers are utilized in almost every maintenance and rehabilitation application. These mix types require smaller maximu...
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