Assessment of Warm-Mix Asphalt for Heavy Traffic Airfields

Abstract

This paper presents the results of tests of warm-mix asphalt (WMA) mixtures designed for airfield pavements. The study was conducted in two phases. The first phase included laboratory tests on 11 WMA technologies. The tests in Phase 2 were performed on three WMA mixtures and one hot-mix asphalt (HMA) mixture produced in an asphalt plant. The evaluation included performance tests to assess WMA susceptibility to permanent deformation and moisture damage compared with that of HMA produced with the same aggregate blend. Test results indicated that WMA potentially was a viable product for surface mixtures on airfield pavements. Although WMA exhibited poorer performance than HMA in moisture damage tests on laboratory-produced specimens, the plant-produced mix indicated little difference compared with HMA. Rutting potential for WMA was somewhat greater than for HMA for mixtures produced both in the laboratory and in an asphalt plant according to asphalt pavement analyzer and Hamburg wheel tracking tests. Differences in performance of WMA mixtures were not attributed to a specific WMA technology category. Variations in performance test results between laboratory-produced specimens and plant-produced specimens were noted and indicated a need to require performance testing as part of a comprehensive quality assurance plan.

Binder and Mixture Testing to Assess Rutting Performance of Warm Mix Asphalt (WMA)

“…Actual plant production temperatures varied but were approximately 143 o C (290 o F) for the HMA and 121 o C (250 o F) for the WMA mixes, respectively. Additional plant production details are provided in Rushing et al (2013). …”

“…As a result, WMA is increasingly being used to improve the sustainability of asphalt concrete for highway pavement applications (NAPA, 2009). However, use of WMA for commercial and military airfield applications has been limited (Su et al, 2009;Rushing et al, 2013). The primary reason for this is the lack of documented design and performance data for airfield use and rutting performance concerns; the use of WMA for airfield paving applications will likely increase if these concerns can be alleviated.…”

Rutting performance of cold-applied asphalt repair materials for airfield pavements

“…St ranged from 8 to 12 psi and increased very slightly with cure time, though the trend is not strong. For comparison, Rushing et al (2013) presents St data for multiple WMA mixes evaluated for use on heavy traffic airfields. For laboratory-produced WMA, St values from 275 to 390 psi were reported.…”

Long-Term Field Transverse Cracking Performance of Warm-Mix Asphalt Pavement and Its Significant Material Property

“…At each temperature, six loading frequencies-20, 10, 5, 1, 0.1, and 0.01 Hz-were applied. The tests [12]: e.g., Sasobit Chemical additive [17]: e.g., Evotherm, Cecabase, and Rediset Foaming [18]: water-based foaming [12], e.g., foaming, Aqublack, Astec DBG, Gencor, and LEA and water-containing foaming [7], e.g., Advera and Aspha-min Climate zone Dry freeze [6] Wet freeze [10] Dry no-freeze [4] Wet no-freeze [8] Service years Between 4 and 5 years [11] Between 5 and 7 years [10] Between 7 and 11 years [7] Pavement structure Gravel base or flexible pavement [20] PCC or cement-stabilized base [8] Traffic volume ESAL < 3 million [18] ESAL ≥ 3 million [10] Aggregate type Limestone [10] Basalt [2] Mixed [5] Other [3] NA [8] Antistripping usage Yes [12] No [12] NA [4] RAP usage Yes [14] No [10] NA [4] Note: Numbers in brackets indicate the number of projects. PCC = portland cement concrete; ESAL = equivalent single-axle load; RAP = reclaimed asphalt pavement; NA = not available.…”

“…Research into the effects of WMA and HMA on transverse cracking has focused mainly on short-term or early-age performance (1-4), Most conclusions from performance comparisons of WMA and HMA have been based on laboratory-fabricated specimens (1,2) or field cores extracted from the pavement less than 3 years after construction (3,4). However, it is also critically important to understand how WMA pavements perform in the long term compared with HMA pavements, to provide recommendations for best practices in the use of WMA.…”