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Journal ArticleDOI

Role of Bending Beam Rheometer Parameters in Thermal Stress Calculations

01 Jan 2004-Transportation Research Record (Transportation Research Board of the National Academies)-Vol. 1875, Iss: 1875, pp 9-13
TL;DR: In this article, the role played by the stiffness and the m-value in the development of thermal stresses in asphalt pavements was investigated, and the analysis showed that thermal stress magnitude was strongly related to the stiffness magnitude.
Abstract: The development of the Strategic Highway Research Program lowtemperature binder specifications was based on the observation that asphalt mixture creep stiffness at 2 h correlated well with instances of transverse cracking. With the correlation extended to asphalt binder stiffness and with time-temperature superposition, a maximum stiffness value was imposed on the binders, and a limiting temperature at which the stiffness at 60 s reached the limiting value was selected as a specification criterion. In addition, the slope at 60 s of the stiffness-versus-time curve on a double logarithmic scale, the so-called m-value, was introduced as an additional criterion. The role played by the stiffness and the m-value in the development of thermal stresses in asphalt pavements was investigated. The analysis showed that thermal stress magnitude was strongly related to the stiffness magnitude. At similar stiffness levels, higher m-values resulted in the faster development of thermal stresses.
Citations
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Journal Article
TL;DR: In this paper, a detailed beam preparation procedure was developed for both laboratory compacted and field cores, and a detailed loading procedure was determined and it was determined that good results can be obtained using the current BBR device at 22 deg C and 10 deg C.
Abstract: This Innovations Deserving Exploratory Analysis (IDEA) project investigated the idea of performing creep tests on asphalt mixture beam specimens with the Bending Beam Rheometer (BBR). In the first part of the investigation a detailed beam preparation procedure was developed for both laboratory compacted and field cores. A detailed loading procedure was developed and it was determined that good results can be obtained using the current BBR device at 22 deg C and 10 deg C. Based on BBR and indirect tension (IDT) experimental data for 20 laboratory mixtures a simple linear relationship was obtained between the IDT creep stiffness and the BBR creep stiffness obtained at 22 deg C and 10 deg C. A similar relation could not be identified for the field samples. The representative volume element (RVE) of asphalt mixtures at low temperatures was investigated by performing three-point bending creep tests on beams of three different sizes. The finite element simulations for a homogeneous asphalt mixture produced similar results for IDT and BBR, within 4% of each other, similar to the experimental results for two polymeric materials. Additional simulations indicated that aggregate spatial distribution in asphalt mixtures is very important and aggregate structure within the mixture should be taken into account when using an inverse model to predict the properties of the mixture components. A number of micromechanics models were also evaluated. A draft specification for obtaining low temperature creep stiffness of asphalt mixtures using the BBR was developed and will be presented at the next Asphalt Mixture Expert Task Group meeting for further comments. A draft specification will be submitted to the American Society for Testing and Materials.

76 citations

Journal ArticleDOI
TL;DR: In this article, the effect of the glass transition behavior on the rate and magnitude of physical hardening was studied for modified and unmodified asphalt binders, and it was shown that the rate of hardening peaks at the glass-transition temperature and becomes relatively insignificant beyond the limits of a glass transition region.

72 citations

Journal ArticleDOI
TL;DR: In this paper, a study was conducted to evaluate rutting, fracture and thermal cracking resistance behavior of asphalt mastic containing inert and active fillers, and the results showed that the aging resistivity increased with the inclusion of hydrated lime (HL) filler.

52 citations

Journal ArticleDOI
TL;DR: Asphalt binders have been shown to undergo significant time-dependent stiffening when stored at low temperatures and this physical hardening has a significant effect on the laboratory performance of a...
Abstract: Asphalt binders have been shown to undergo significant time-dependent stiffening when stored at low temperatures. This physical hardening has a significant effect on the laboratory performance of a...

37 citations

Journal ArticleDOI
TL;DR: In this article, the authors discuss the effect of reversible aging on the durability of asphalt pavement in cold and high altitude areas, and the importance of the aging factor on asphalt pavement.
Abstract: Thermoreversible aging is an important factor that affects the durability of asphalt pavement in cold and high altitude areas. Although there has been increasing attention to the significance of th...

30 citations

References
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Journal ArticleDOI
TL;DR: In this paper, the creep function for the National Bureau of Standards polyisobutylene at 25°C was calculated from the relaxation function, using the integral equation connecting them, and the calculated function was shown to be correct in its initial slope, to satisfy the inequality φ(t)ψ(t )⩽1 throughout, and to approach satisfactorily the independently determined asymptote.
Abstract: The creep function for the ``National Bureau of Standards'' polyisobutylene at 25°C is calculated from the relaxation function, using the integral equation connecting them. The calculated function is shown to be correct in its initial slope, to satisfy the inequality φ(t)ψ(t)⩽1 throughout, and to approach satisfactorily the independently determined asymptote.

205 citations

01 Jan 1993

191 citations


"Role of Bending Beam Rheometer Para..." refers background or methods in this paper

  • ...The development of the Strategic Highway Research Program (SHRP) asphalt binder criterion for low-temperature cracking was based on the assumption that the 2-h mixture stiffness correlated well with the severity of thermal cracking in the field (1)....

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  • ...To expedite the testing process, the time–temperature superposition principle was used to show that, for asphalt binders in general, the stiffness at 60 s at temperature T1°C is approximately equal to the stiffness at 2 h at temperature T1−10°C (1)....

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Journal ArticleDOI

180 citations


"Role of Bending Beam Rheometer Para..." refers methods in this paper

  • ...The Microsoft Excel spreadsheet has built-in macros that (a) fit the CAM model to the experimental BBR data, (b) obtain stiffness master curves, (c) convert the creep compliance to relaxation modulus using the Hopkins and Hamming algorithm (5), (d) fit the CAM model to the relaxation modulus, (e) solve the hereditary integral, and ( f ) obtain thermal stress as a function of temperature....

    [...]

01 Jan 2000
TL;DR: In this paper, a semi-empirical mechanistic approach was proposed to determine the critical cracking temperature of asphalt pavements using stiffness data from the Bending Beam Rheometer (BBR) to predict thermal stress.
Abstract: The main objective of this paper is to describe the development of a comprehensive semi-empirical mechanistic mode to determine the critical cracking temperature of asphalt pavements. This model uses stiffness data from the Bending Beam Rheometer (BBR) to predict thermal stress in binder. The thermal stress in the hot-mix pavement is computed using a damage transfer function called the Pavement Constant (PC). To determine critical cracking temperature , the pavement thermal stress is compared with the binder tensile strength measured using the Direct Tension Test (DTT). This model was used to develop a low-temperature criterion for use as a binder specification. In this specification, the low-temperature binder performance grade is determined by comparing the thermal stress in the pavement with the binder failure stress. If the binder failure stress exceeds the thermal stress at the specification temperature, the binder is considered a "pass." The semi-empirical model was calibrated using the binder properties and the hot-mix properties from the Lamont Test Road in Alberta, Canada. Further validation was obtained from analysis of the Elk County Test Road in Pennsylvania, as well as for two widely used polymer-modified asphalts with anecdotal, but extensive, performance data.

91 citations


"Role of Bending Beam Rheometer Para..." refers background in this paper

  • ...The new MP1a specification incorporates a thermoviscoelastic model (6) that calculates thermal stresses by solving the following hereditary integral:...

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