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From page 53... ... 53 C H A P T E R 4 The test methods and metrics described in Chapter 2 were employed in various field settings to evaluate their applicability to on-site locations, their usefulness in describing the binder foaming characteristics of various plant foaming units, and their ability to differentiate specimens prepared in the laboratory and the field. In addition, the proposed foamed mix design was validated with plant data. Read the entire page →
From page 54... ... 54 Figure 4-1. Counterflow drum plant, Austin, Texas. Read the entire page →
From page 55... ... 55 From the ERmax and k-value results for the first binder that are presented in Figure 4-4, it is apparent that the container size did have an influence in the measurements, with higher ER and k-value for the 1-gallon can measurements versus the measurements performed in the 5-gallon bucket. This difference was more pronounced at higher water contents (i.e., 5.5%) Read the entire page →
From page 56... ... 56 factor of 2.0. The error bars in Figure 4-6 span ±1 standard deviation from the average ERmax value. Read the entire page →
From page 57... ... 57 A.4.2. Indirect Tensile Strength Test Three specimens were tested in a dry condition and three specimens after moisture conditioning following the procedure outlined by AASHTO T 283. Read the entire page →
From page 58... ... 58 mixture versus the control HMA at the test temperature of 122°F (50°C) Read the entire page →
From page 59... ... 59 with a Gencor foamer (Figure 4-17) , and the details of the mix being produced during the team's visit are given in the following. Read the entire page →
From page 60... ... 60 line from the sampling port was 1 in. in diameter and 10 in. Read the entire page →
From page 61... ... 61 Aggregate Source Bin No. Read the entire page →
From page 62... ... 62 B.3. Foaming Measurements Average ERmax and k-value of three replicate measurements performed on-site and two replicate measurements performed in the laboratory using the Wirtgen foamer are presented in Figure 4-26. Read the entire page →
From page 63... ... 63 were smaller and lasted longer. The SAI values decreased progressively as the water content increased. Read the entire page →
From page 64... ... 64 mixture at 1.0% foaming water content. Thus, the inclusion of water from the foaming process had no significant effect on the mixture stiffness. Read the entire page →
From page 65... ... 65 Barrel with a Stansteel Accushear foaming unit. The foaming unit was located on its own platform (Figure 4-35) Read the entire page →
From page 66... ... 66 minimum water content the equipment was able to output) Read the entire page →
From page 67... ... 67 Aggregate Source Bin No. Read the entire page →
From page 68... ... 68 ±1 standard deviation from the average value. As illustrated, a lower tmax value was exhibited for the control HMA versus the laboratory-foamed mixture with 5.5% water content, indicating that plant-produced HMA had a better workability than the foamed mixture. Read the entire page →
From page 69... ... 69 to a point where the maximum shear stress increases again (Figure 4-46) Read the entire page →
From page 70... ... 70 the oven for 1 hour. Once the temperature achieved 275°F (135°C) Read the entire page →
From page 71... ... 71 that plant-produced foamed mixture at 1.5% foaming water content had a better rutting resistance than the HMA counterpart, as indicated by a lower DevpSN value. Thus, better moisture susceptibility and rutting resistance were exhibited by the plant-produced foamed mixture at 1.5% foaming water content than by the HMA counterpart in the HWTT. Read the entire page →
From page 72... ... 72 (25°C) was achieved between the foamed mixture at 1.5% foaming water content and the control HMA. Read the entire page →
From page 73... ... 73 resistance, as indicated by lower DevpSN values, was exhibited by foamed mixtures at the optimum foaming water content as compared to their HMA counterparts. Thus, better rutting resistance was exhibited by the mixtures produced with 1.5% foaming water content versus their HMA counterparts in the HWTT. Read the entire page →

From page 53...

... 53 C H A P T E R 4 The test methods and metrics described in Chapter 2 were employed in various field settings to evaluate their applicability to on-site locations, their usefulness in describing the binder foaming characteristics of various plant foaming units, and their ability to differentiate specimens prepared in the laboratory and the field. In addition, the proposed foamed mix design was validated with plant data.