The National Academies Press

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From page 14... ... 14 Experimental Plan Introduction As illustrated in Figure 2-1, the research plan included several tasks generally organized into three parts. The first part included identifying field projects -- constructed prior to this study -- that used well-documented mixtures containing RAS and WMA. Read the entire page →
From page 15... ... 15 Figure 2-1. Flow chart illustrating the research plan. Read the entire page →
From page 16... ... 16 Parameter Project 1 Project 2 Project 3 Project 4 Project 5 Location Larsen, Wisconsin Enterprise, Alabama Oak Ridge, Tennessee Wilson, North Carolina La Porte, Indiana Project date 09/2013 06/2014 10/2014 06/2015 9/2015 No. of mixtures 3 4 2 4 2 Mix variable WMA versus HMA WMA versus HMA and Design Air Voids WMA versus HMA PC versus MW WMA versus HMA WMA technology Zycotherm and Rediset Gencor Foamer Evotherm M1 Evotherm 3G Foaming Design air voids 4.0 4.0 and 3.5 4.0 4.0 4.0 Road STH 96 US 84 TN 170 SC 42 SR 39 ESAL range (million) Read the entire page →
From page 17... ... 17 materials obtained from new projects where the same mixture was produced as HMA and WMA. Engineering properties of plant-produced WMA and HMA were used for paired statistical comparisons. Read the entire page →
From page 18... ... 18 course of this project, most discussions with regard to the DTc parameter among asphalt researchers were based on tests conducted after the standard 20-h pressure aging vessel (PAV) aging for PG testing. Read the entire page →
From page 19... ... 19 The collected data were used to generate a master curve for each individual mix. The master curve uses the principle of time–temperature superposition to horizontally shift data at multiple temperatures and frequencies to a reference temperature so that the stiffness data can be viewed without temperature as a variable. Read the entire page →
From page 21... ... 21 and NCHRP Report 691 for HMA and WMA, respectively (Table 2-8) Read the entire page →
From page 22... ... 22 Flow number is defined as the number of cycles at which the sample begins to rapidly deform and coincides with the minimum rate of strain accumulation measured during the test. This is more properly defined as the breakpoint between steady-state rutting (secondary rutting) Read the entire page →
From page 23... ... 23 used to record load cycles, applied loads, and beam deflections. The software also computed and recorded the maximum tensile stress, maximum tensile strain, phase angle, beam stiffness, dissipated energy, and cumulative dissipated energy at user-specified load cycle intervals. Read the entire page →
From page 24... ... 24 applied for 0.1 s and then followed by a 0.9-s rest. The resilient modulus is calculated using the stress–strain curve, as shown in Figure 2-10a. Read the entire page →
From page 25... ... 25 kit designed for the IPC Global Asphalt Mixture Performance Tester. For this test, samples with a 150-mm diameter and a 125-mm target height were produced using the Superpave Gyratory Compactor. Read the entire page →
From page 26... ... 26 were then cut along the center diameter of the specimen, yielding two semicircular halves. To reduce the effect of mixture variation between specimens, each half of the specimen was designated with the same notch depth (i.e., 25.4 mm, 31.8 mm, or 38.1 mm) Read the entire page →
From page 27... ... 27 Figure 2-13. Semi-Circular Bend Test. Read the entire page →
From page 28... ... 28 Figure 2-15. Typical plot specimen notch versus area to peak load. Read the entire page →
From page 29... ... 29 Additional Testing and Analysis of Mixtures Containing RAS In addition to the primary experiments focused on the production, field performance, and engineering properties of plant-produced HMA and WMA mixtures containing RAS, this project also explored research along three other areas to gain a better understanding of the behavior of RAS in asphalt mixtures. The first study explored the use of differential scanning calorimetry to determine thermal energy required to identify the phase change (melting point) Read the entire page →

From page 14...

... 14 Experimental Plan Introduction As illustrated in Figure 2-1, the research plan included several tasks generally organized into three parts. The first part included identifying field projects -- constructed prior to this study -- that used well-documented mixtures containing RAS and WMA.