Warm Mix Asphalt Additives

The PG system is based on project climate. The standard notation for PG binder is PG XX-YY where XX is the average seven-day maximum pavement design temperature and YY is the minimum pavement design temperature (33). 

Several PG asphalt binders were used in combination with nonfoaming warm mix asphalt additives, i.e., Cecabase , Evotherm , Rediset , and Sasobit . 

Tradenames appearing in the references are shown in Table 4.12. Table 4.12 Tradenames in References. 

Surfam (Series) Mars Chemical Company, Atlanta, Ga. 

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Austerman A.J., WS. Mogawei and R. Bonaquist. 2009. Investigation of the influence of warm mix asphalt additive dose on the workability, cracking susceptihility, and moisture susceptihility of asphalt mixtures containing reclaimed asphalt pavement. Proceedings of 54th Annual Conference of the Canadian Technical Asphalt Association. Laval, Quebec, Canada Polyscience Publications Inc. 

Warm mix asphalts (WMAs) are asphalts produced, handled and compacted at temperatures lower than those of conventional hot asphalts. This is achieved by lowering the viscosity of the binder using additives or applying foaming processes, both known as WMA systems. The aggregate mix gradation is the same as for the hot mix variety. 

When recycling is predominant, the hot aggregate, fines and reclaimed asphalt pass through the double-barrel and mixing takes place in a twin-shaft pugmill or rotary mixer. Hence, the double-barrel dryer/mixer is called double RAP dryer (ASTEC Industries Inc. 2014). With the addition of the Green Pac, an option offered by the same company, the double RAP dryer produces warm mix asphalt. 

The asphalts (hot, warm, semi-warm mixed or cold mixed) used for the construction of asphalt base, binder course and surface layers together with their mechanical and other properties are described in detail in Chapters 5, 6 and 7. In addition, details on their production, laying, compaction and control of quality can be found in Chapters 8 and 9. 

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