Cold Weather Paving Using Warm Mix Asphalt Technology

摘要

A new technology involving asphalt cement modified with HyperTherm was used to demonstrate thatrnwarm mix asphalt technology can be used to extend the paving season by facilitating paving in coldrnweather.rnHyperTherm was initially validated as an effective warm mix technology during an overlay project onrnKatimavik Road in the City of Ottawa. The job involved the City of Ottawa new 4.75 mm FC1 mixrnintended for traffic level C (3 to 10 million ESAL’s) placed at nominal 25mm thickness. PG 58-28rnmodified with HyperTherm was used as the asphalt cement. The warm-mix was produced at about 120℃rnat the plant and compacted at between 75℃ – 90℃. This corresponds to reductions in mixing andrncompaction temperatures as compared to conventional hot mix using the same grade of asphalt cement.rnVisible emissions and odours during the production and placement of the mix were also reduced.rnPhase two of the study utilized the improved mix workability properties imparted by warm mix technologyrnto extend the paving season in a cold weather application. Oxford Road 4 in the County of Oxford,rnOntario was paved with PG 58-28 modified with HyperTherm during the month of December. Byrnproducing the mix at conventional hot mix temperatures, compaction targets were achieved despite the lowrnambient air temperature and frozen granular grade. The improved workability imparted by the warm mixrnadditive counteracted the cold weather conditions.