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Asphalt and Emulsions
Published in Rajib B. Mallick, Tahar El-Korchi, Pavement Engineering, 2017
Rajib B. Mallick, Tahar El-Korchi
The dynamic shear rheometer (DSR; test method: AASHTO T-315; see Figure 9.10) is used to characterize the viscoelastic behavior of asphalt binder, and evaluate its rutting and cracking potential. The basic principle used for DSR testing is that asphalt behaves like elastic solids at low temperatures and like a viscous fluid at high temperatures. These behaviors can be captured by measuring the complex modulus (G*) and phase angle (δ) of an asphalt binder under a specific temperature and frequency of loading. The G* and δ parameters (Figure 9.10) are measured by the DSR by applying a torque on the asphalt binder between a fixed and an oscillating plate, and measuring the resultant strain. G* is defined as the ratio of shear stress to shear strain, and δ is the time lag between the stress and the strain in the asphalt binder. These properties are determined at high and intermediate pavement service temperatures. The high temperature is determined from the average of maximum HMA pavement temperature over a 7 day period through summer, which is obtained from data from weather stations. The intermediate testing temperature is determined from an average of 7 day average maximum and minimum design temperature. Figure 9.11 shows results of DSR tests conducted on different asphalts at different temperatures. Dividing G* by the angular velocity (10 rad/s used in DSR testing), one can obtain complex dynamic shear viscosity from DSR tests.
Euphorbia Tirucalli plant: Application in bituminous prime coat
Published in Andreas Loizos, Imad L. Al-Qadi, A. (Tom) Scarpas, Bearing Capacity of Roads, Railways and Airfields, 2017
L.M. Gondim, S.A. Soares, S.H.A. Barroso, C.M.C. Alecrin
The neat and modified asphalt binder were submitted to the following tests Fourier Transform Infrared Spectroscopy (FTIR), absorbance spectrum, in the region of 4000–400 cm−1 wave numbers, in transmission module, using liquid cell and solutions on Carbon Disulfide;Penetration at 25°C (ASTM D5);Softening Point (ASTM D36);Rotational Viscosity in Brookfield® viscometer, (ASTM D 4402), using spindle 21, at 135°C, 150°C e 177°C and shear rate of 20 rpm.Frequency Sweep Test in a Dynamic Shear Rheometer (DSR), under stress-controlled mode (120 Pa), over a range of frequencies (0.01–100Hz) (ASTM D7175). The samples were tested at high temperatures only (45°C −85°C).
Effect of spindle diameter and plate gap on the rheological properties of asphalt binders
Published in Sandra Erkens, Xueyan Liu, Kumar Anupam, Yiqiu Tan, Functional Pavement Design, 2016
Bhupendra Singh, Nikhil Saboo, Praveen Kumar
Dynamic Shear Rheometer (DSR) is one of the most widely used instrument to study the rheological properties of the asphalt binder. With the help of rheometer different rheological properties such as complex modulus, phase angle, creep compliance etc. are studied. In DSR two different spindle of diameters 8 mm and 25 mm are used. 8 mm diameter spindle is used to test samples at lower temperatures i.e. 0–30 ºC whereas 25 mm diameter spindle is used for higher temperatures i.e. 40–90 ºC. American Association of State Highway and Transportation Officials (AASHTO) recommends 2 mm gap between parallel for 8 mm spindle and 1 mm gap for 25 mm diameter spindle which is based on the extensive experiment and research results. Strategic Highway Research Program (SHRP) suggests the following spindle diameters for different conditions and binder stiffness:
The influence of filler type and gradation on the rheological performance of mastics
Published in Road Materials and Pavement Design, 2019
K. Rieksts, M. Pettinari, V. Haritonovs
Dynamic shear rheometer (DSR) is typically used to measure and evaluate rheological characteristics of viscous materials by applying shear force to specimen (Bai, Yang, & Zeng, 2014). DSR can work in two modes – controlled stress or controlled strain (Hafeez & Kamal, 2014; Shenoy, 2008). During this study, multiple stress creep recovery test (MSCRT) method was used applying a constant stress conditions to the sample. RV has a substantial effect altering the values of non-recoverable creep compliance (Jnr) and viscosity (D’Angelo & Dongré, 2009; Elnasri, Airey, & Thom, 2013). Jnr is a parameter calculated based on the strain levels during the tests while the viscosity is measured directly during loading cycle. Both of these parameters are very reliable regarding describing the changes in stiffening of mastic (Faheem, Hintz, Bahia, Al-Qadi, & Glidden, 2012; Mehta et al., 2013).
A study of top-down cracking in the state of Oregon
Published in Road Materials and Pavement Design, 2018
Md S. Rahman, Joseph H. Podolsky, R. Christopher Williams, Todd Scholz
Laboratory testing on the extracted asphalt mixture cores included dynamic modulus and indirect tensile (IDT) strength testing in a diametrical test configuration over a range of temperatures and at multiple frequencies. The asphalt binder was then extracted and recovered from the cores for subsequent rheological testing for asphalt binder grade determination. The asphalt binder grading included dynamic shear rheometer (DSR) and bending beam rheometer (BBR) testing for performance grade (PG) determination. Furthermore, the recovered aggregate was tested for gradation, and coarse and fine aggregate angularity. Table 3 lists all the tests that were performed on the asphalt cores, and extracted asphalt binder and aggregate.
Assessment of methods to select optimum doses of rejuvenators for asphalt mixtures with high RAP content
Published in International Journal of Pavement Engineering, 2023
Diana B. Sánchez, Silvia Caro, Allex E. Alvarez
Figure 1 shows a summary of the testing plan. In the figure, ‘DSR’ refers to the Dynamic shear rheometer test, which consists of a shear oscillatory test under strain-controlled conditions used to quantify the linear viscoelastic material properties (|G*| and δ) at a specific temperature and frequency conditions. It is noteworthy that for the SFE method, the recycled binder blends were only tested in the unaged state since this is the first time the method is attempted –so it was important to assess its potential initially in unaged state–, and because there is currently no consensus in the literature regarding the impact of ageing on the SFE of asphalt binders (Grenfell et al. 2015, Wang et al. 2020).