Short-Term Laboratory Conditioning of Asphalt Mixtures (2015) / Chapter Skim
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From page 25... ...
25 Findings and Applications This chapter provides the mixture test results for the Phase I and Phase II experiments. Mixture volumetrics, stiffness, and HWTT results are summarized and analyzed for simulating plant aging and examining the effects of the selected factors on plant aging.
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From page 26... ...
26 Field Site Mixture Type PMPC LMLC Gmm Pba Pbe FT Gmm Pba Pbe FT Texas I HMA 2.420 0.53 4.70 9.09 2.397 0.10 5.11 9.88 Evotherm 2.408 0.30 4.91 9.50 2.399 0.13 5.07 9.81 Foaming 2.400 0.15 5.06 9.77 2.407 0.28 4.93 9.53 HMA + RAP/RAS 2.410 0.83 4.42 7.89 2.418 0.98 4.27 7.64 Evotherm + RAP/RAS 2.420 1.02 4.24 7.58 2.417 0.96 4.29 7.67 New Mexico HMA 2.342 0.41 5.01 10.21 2.329 0.16 5.25 10.70 HMA + RAP 2.340 0.66 4.78 9.66 2.339 0.64 4.79 9.70 Evotherm + RAP 2.343 0.72 4.72 9.55 2.333 0.52 4.91 9.93 Foaming + RAP 2.335 0.56 4.87 9.85 2.349 0.84 4.61 9.32 Connecticut HMA + RAP 2.676 1.26 3.71 8.55 2.652 0.90 4.04 9.33 Foaming + RAP 2.675 1.24 3.72 8.59 2.658 0.99 3.96 9.14 Wyoming HMA 2.470 0.76 4.28 8.81 2.491 1.13 3.93 8.09 Evotherm High T 2.479 0.92 4.13 8.50 2.494 1.18 3.88 7.98 Evotherm Ctrl T 2.487 1.06 3.99 8.22 2.501 1.30 3.76 7.75 Foaming High T 2.485 1.03 4.03 8.29 2.497 1.24 3.83 7.88 Foaming Ctrl T 2.470 0.76 4.28 8.81 2.505 1.37 3.70 7.61 South Dakota HMA + RAP 2.441 0.58 4.75 7.28 2.441 0.58 4.75 7.28 Evotherm + RAP 2.440 0.56 4.77 7.31 2.440 0.56 4.77 7.31 Foaming + RAP 2.428 0.35 4.97 7.62 2.440 0.56 4.77 7.31 Advera + RAP 2.432 0.42 4.90 7.51 2.432 0.42 4.90 7.51 Iowa High Abs HMA + RAP High T 2.425 2.35 4.82 10.18 2.373 1.35 5.75 12.14 High Abs HMA + RAP Ctrl T 2.439 2.61 4.57 9.67 2.373 1.35 5.75 12.14 High Abs Foaming + RAP High T 2.435 2.54 4.64 9.81 2.365 1.19 5.89 12.45 High Abs Foaming + RAP Ctrl T 2.437 2.57 4.61 9.74 2.373 1.35 5.75 12.14 Low Abs HMA + RAP High T 2.481 0.61 4.42 9.28 2.482 0.63 4.40 9.25 Low Abs HMA + RAP Ctrl T 2.476 0.52 4.50 9.46 2.479 0.58 4.45 9.35 Low Abs Foaming + RAP High T 2.477 0.54 4.49 9.42 2.488 0.73 4.30 9.04 Low Abs Foaming + RAP Ctrl T 2.474 0.49 4.54 9.53 2.489 0.75 4.29 9.00 Indiana HMA + RAP BMP 2.451 1.31 4.77 8.12 2.458 1.32 4.65 7.92 HMA + RAP DMP 2.446 1.48 5.00 8.55 2.443 1.43 5.05 8.64 Advera + RAP BMP 2.448 1.29 4.84 8.24 2.456 1.43 4.71 8.02 Foaming + RAP DMP 2.455 1.43 4.73 8.06 2.440 1.16 4.98 8.49 Florida High Abs HMA + RAP 2.350 2.03 4.66 6.93 2.341 1.86 4.83 7.17 High Abs Foaming + RAP 2.363 2.18 4.37 6.48 2.365 2.22 4.33 6.43 Low Abs HMA + RAP 2.537 0.79 3.74 5.61 2.540 0.84 3.70 5.54 Low Abs Foaming + RAP 2.548 1.09 3.64 5.46 2.540 0.96 3.76 5.65 Texas II HMA BMP Binder A 2.402 1.39 5.06 7.97 2.393 1.11 5.11 8.10 HMA DMP Binder A 2.415 1.34 4.65 7.28 2.393 1.11 5.11 8.10 HMA BMP Binder V 2.395 1.26 5.19 8.17 2.392 1.16 5.21 8.20 HMA DMP Binder V 2.411 1.26 4.71 7.38 2.392 1.16 5.21 8.20 Table 3-1. Mixture volumetrics for PMPC and LMLC specimens.
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27 the PMPC specimens. The biggest explainable exceptions are for the high-absorption mixes from Iowa, which were affected by the laboratory conditioning; the high-RAP mixture from New Mexico; and the rapidly aging asphalt mixture from Texas II.
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28 site, which showed a significantly lower E* stiffness compared to its corresponding LMLC counterpart.
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29 in Figure 3-8, there is a reasonable correlation, as indicated by a scattering around the line of equality, in terms of rutting resistance between LMLC specimens and their corresponding PMPC specimens. The reduced correlation observed for specimens with high rut-depth values (i.e., 6 to 12 mm at 5,000 load cycles)
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30 equivalent level of oxidation during the plant production and construction as those binders extracted and recovered from the LMLC specimens fabricated using the STOA protocols of 2 hours at 275°F (135°C) for HMA and 2 hours at 240°F (116°C)
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31 Thus, this study verified the simulation of binder or mixture aging during plant production and construction by the laboratory STOA protocols of 2 hours at 275°F (135°C)
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32 were above the line of equality, indicating a better rutting resistance in the HWTT for HMA than WMA. It may also be noticed that the data scatter tends to increase with larger values.
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33 of E* stiffness for HMA versus WMA, with the exception of BMP PMPC specimens from the Indiana field site, the E*
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34 mixtures, and the y-axis coordinate represents corresponding test results for BMP-produced mixtures. The black solid line is the line of equality, and the red dashed line illustrates the shift from the line of equality for MR stiffness or rut depth measurements in the HWTT.
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35 the RAP/RAS mixtures were produced using a softer PG 64-22 binder in conjunction with 15 percent RAP and 3 percent RAS. The RAP came from a stockpile at Ramming Paving in Austin, Texas, and the RAS was from tear-off shingles ground to 100 percent passing the 0.5-in.
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36 The MR stiffness comparison for mixtures using high- versus low-absorptive aggregates in Figure 3-25 shows that most of the data points are above the line of equality, indicating a higher MR stiffness for mixtures using low-absorptive aggregates compared to those with high-absorptive aggregates. As evident in Figure 3-25, mixtures with highly absorptive aggregates may produce results that are variable when they are subjected to the recommended STOA.
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37 (a) BMP PMPC Specimens (b)
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39 in colder climatic zones, including Wyoming, South Dakota, Iowa, and Indiana, due to differences in pavement in-service temperatures. Additionally, the construction date has a significant effect on the CDD value and a subsequent effect on field aging of asphalt mixtures.
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40 Figures 3-30 and 3-31, it is reasonable to use the MR ratio or HWTT RRP ratio as a function of CDD values to quantify mixture aging in the field. Figures 3-32 and 3-33 present the continuous PG results for extracted and recovered binders from cores at construction and post-construction from the Indiana and Florida field sites, respectively.
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41 aging. They were defined as the ratios of binder or mixture properties of short-term aged specimens to those properties of long-term aged specimens.
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42 The DSR G* results measured at 77°F (25°C)
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43 in the field. Note that the correlation illustrated in Figure 3-40 was determined based on a limited amount of binder FT-IR CA results and therefore the cross points for LTOA protocols of 2 weeks at 140°F (60°C)
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44 the long-term aging for WMA was more significant than that for HMA. As the results of Phase I showed, in general, WMA mixtures begin their service lives with lower stiffness and tend to age in place more rapidly, as shown in Figures 3-41 and 3-42, but ultimately their stiffness and rutting resistance are comparable to HMA.
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45 and HMA (CDDWMA=HMA) can be determined, as expressed in Equation (3-3)
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46 in-service time corresponding to CDDWMA=HMA0 of 3,000 CDD, approximately 2 months and 3 months were required in warmer climates and colder climates, respectively. For the statistical analysis (see Appendix E)
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47 LTOA protocols of 5 days at 185°F (85°C) and 2 weeks at 140°F (60°C)
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48 The MR ratio results shown in Figure 3-47 illustrate that the data points align below the line of equality, indicating a significantly higher increase in MR stiffness after long-term aging for the control mixtures compared to the RAP/RAS mixtures. The greater sensitivity to aging exhibited by the control mixtures can possibly be attributed to the larger amount of virgin binder in the mixture, which is likely more susceptible to aging.
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From page 49... ...
49 technology* aggregate absorption were statistically significant at a = 0.05.
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