SELECTING WARM MIX ASPHALT ADDITIVES BY THE PROPERTIES OF Warm Mix Asphalt MIXTURES ‒ CHINA EXPERIENCE

The objective of this research was to select the most effective warm asphalt additives for mix practice based
on a series of laboratory testing programs such as density, Marshall stability, freeze-thaw splitting strength, dynamic
stability, and bending beam strain. The experimental design of warm mix asphalt included the use of three commonlyused
additives, two typical aggregate gradations, one crushed aggregate, and one modified asphalt. Results showed that:
(1) the bulk specific gravity and air voids of all the mix specimens were similar to those of controls; (2) the Marshall
stability and flow values of the warm stone mastic asphalt were 6.8%–26.6% and 3.5%–10.3%% higher than those of
controls, respectively, and those of the warm asphalt concrete were 6.1%–15.6% and 6.5%–9.7% higher than those of
controls, respectively; (3) the indirect tensile strength of two types of mixtures was 1.7%–14.4% lower than that of controls,
and the average tensile strength ratio of the warm stone mastic asphalt and asphalt concrete was 4.3% and 1.3%
higher than that of controls, respectively; (4) the dynamic stability of warm mix specimens was 10.8%–16.6% lower
than that of the controls; (5) the average bending failure strain of warm stone mastic asphalt was 7.6% higher than that
of the controls, and that of warm asphalt concrete was 12.8% lower than that of the controls; (6) Overall, warm asphalt
mixtures with Sasobit and Rediset had relatively best performances required in Southeast China, where rutting and
stripping are the main failures of asphalt pavements