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We introduce a novel method that could modify neat asphalt. A polymer-forming monomer, dimethylphe- nol(DMP) was added to the neat asphalt and polymerization was occurred autonomously, without adding any external catalyst for the... more
We introduce a novel method that could modify neat asphalt. A polymer-forming monomer, dimethylphe- nol(DMP) was added to the neat asphalt and polymerization was occurred autonomously, without adding any external catalyst for the polymerization, only with oxygen molecules in the air. The polymer produced in the asphalt was polyphenylene- oxide(PPO) and it enhanced the mechanical properties of the asphalt. Compared with the neat asphalt, the tenacity and toughness of the DMP-modified asphalt were two and half times and three times high, respectively.
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This paper studies static crack growth of asphalt pavement using the extended finite element method (XFEM). To consider nonlinear characteristics of asphalt concrete, a viscoelastic constitutive equation using the Maxwell chain is used.... more
This paper studies static crack growth of asphalt pavement using the extended finite element method (XFEM). To consider nonlinear characteristics of asphalt concrete, a viscoelastic constitutive equation using the Maxwell chain is used. And a linear cohesive crack model is used to regularize the crack. Instead of constructing the viscoelastic constitutive law from the Prony approximation of compliance and retardation time measured experimentally, we use a smooth log-power function which optimally fits experimental data and is infinitely differentiable. The partial moduli of the Maxwell chain from the log-power function make analysis easy because they change more smoothly in a more stable way than the ordinary method such as the least square method. Using the developed method, we can simulates the static crack growth test results satisfactorily.
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Rubblisation is an effective rehabilitation method for deteriorated Portland cement concrete (PCC) pavements due to its low initial costs, minimal traffic disruption and ability to minimise reflective cracking in asphalt overlays.... more
Rubblisation is an effective rehabilitation method for deteriorated Portland cement concrete (PCC) pavements due to its low initial costs, minimal traffic disruption and ability to minimise reflective cracking in asphalt overlays. However, the loss of strength in the PCC slab due to rubblisation creates the demand for a subgrade that is strong enough to handle traffic after rubblisation. This paper presents a research effort to develop an analysis method that allows the realistic estimation of subgrade stiffness after rubblisation from deflection measurements on intact PCC slabs before rubblisation. As a forward model, stress- and strain-dependent nonlinear subgrade models are incorporated into a finite element analysis (FEA). Based on the synthetic database generated from the FEA, different methodologies are developed to predict the coefficients in the nonlinear subgrade model from deflections under multilevel falling weight deflectometer loads.
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... Techniques Sungho Mun* — Ghassan R. Chehab** — Y. Richard Kim*** ... Several methods have been proposed to convert the complex modulus, a LVE response function in frequency domain, to the corresponding relaxation modulus in time... more
... Techniques Sungho Mun* — Ghassan R. Chehab** — Y. Richard Kim*** ... Several methods have been proposed to convert the complex modulus, a LVE response function in frequency domain, to the corresponding relaxation modulus in time domain (Chehab, 2002). ...
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This paper presents the research into the implementation of the viscoelastic continuum damage model (VCDM) of asphalt concrete into a finite element analysis. The VCDM is based on: (1) the elastic-viscoelastic correspondence principle... more
This paper presents the research into the implementation of the viscoelastic continuum damage model (VCDM) of asphalt concrete into a finite element analysis. The VCDM is based on: (1) the elastic-viscoelastic correspondence principle using pseudostrains; (2) the work potential theory for damage modeling; and (3) the time-temperature superposition principle with growing damage. With the aid of Schapery's preceding work, the
Research Interests: Engineering, Civil Engineering, Structural Engineering, Viscoplasticity, Viscoelasticity, and 12 morePotential Theory, Finite element method, Finite Element, Strain Rate, Finite Element Analysis, High Temperature, Finite Element Model, Three Dimensional, Material Model, Correspondence Principle, Superposition principle, and Asphalt concrete
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The deterioration of asphalt concrete pavement is largely divided into cracking and rutting, and cracking is classified into environmental cracking and fatigue cracking. The prediction for the fatigue crack has been based mainly on the... more
The deterioration of asphalt concrete pavement is largely divided into cracking and rutting, and cracking is classified into environmental cracking and fatigue cracking. The prediction for the fatigue crack has been based mainly on the results of laboratory experiments. However, the accelerated pavement testing (APT) is preferred to typical laboratory experiments from the aspect that it can simulate the actual pavement performance better than laboratory experiments. Thus, this paper develops a fatigue model based on the hypothesis of cumulative damage for the asphalt black base using APT and analyzes the correlation between APT results and previous laboratory test results.
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Abstract This paper describes how to determine the fatigue-cracking resistance of hot-mix asphalt (HMA) mixtures and formulate a viscoelastic continuum damage algorithm based on the comparison between measured and calculated strain vs.... more
Abstract This paper describes how to determine the fatigue-cracking resistance of hot-mix asphalt (HMA) mixtures and formulate a viscoelastic continuum damage algorithm based on the comparison between measured and calculated strain vs. stress histories at low temperatures. The fatigue-cracking resistance characteristics evaluated in this study were based on the dynamic modulus test for material stiffness characterization and the constant-crosshead-rate tension test for fatigue-cracking characterization, using dense-graded and lime-modified HMA mixtures. The main contributions of this paper are the methods for determining the optimum asphalt content of the HMA mixtures to improve fatigue-cracking resistance and for evaluating the fatigue-cracking resistance of various HMA mixtures.
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A measuring technique for tire–pavement interaction noise (coast-by noise) that uses a proposed close proximity (CPX) method equipped with surface microphones has been employed to perform pavement noise evaluations on nine different... more
A measuring technique for tire–pavement interaction noise (coast-by noise) that uses a proposed close proximity (CPX) method equipped with surface microphones has been employed to perform pavement noise evaluations on nine different pavement sections as well as two on-site highways. Through field tests, the appropriate noise measuring procedures have been developed and validated for evaluating light and heavy vehicles and various pavement surfaces at varying vehicle speeds. The results show that tire–pavement noise levels vary widely according to the various surface types, vehicle types, and vehicle speeds. In addition, it was found that power-by noise (power-train plus tire–pavement interaction noise) measurements, based on the proposed CPX method, were able to determine the sound power levels used for outdoor sound propagation models.
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ABSTRACT This paper presents a new and efficient method to determine sound power levels (PWLs). PWLs, generally used for modeling outdoor sound simulations, are obtained from sounds that are emitted by various types of vehicles and cause... more
ABSTRACT This paper presents a new and efficient method to determine sound power levels (PWLs). PWLs, generally used for modeling outdoor sound simulations, are obtained from sounds that are emitted by various types of vehicles and cause road traffic noise. Other models, such as HARMONOISE and the ASJ Model, are also based on PWLs. However, a more efficient method is required for determining PWLs from sound pressure levels (SPLs) that typically are measured by field testing and evaluating the influence of different vehicles and road surfaces. The statistical pass-by (SPB) of ISO 11819-1 is used for SPL measurements; however, numerous SPBs must be carried out to reduce measurement uncertainty as well as to satisfy requirements related to meteorological conditions and background noise. In order to alleviate this problem and to make the determination of PWLS more efficient, a testing approach is presented that uses both the novel close proximity (NCPX) method and the pass-by method to determine PWLs.
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ABSTRACT A highway traffic noise prediction model has been developed for environmental assessment in South Korea. The model is based on an outdoor sound propagation method and is fully compliant with ISO 9613 and the sound power level... more
ABSTRACT A highway traffic noise prediction model has been developed for environmental assessment in South Korea. The model is based on an outdoor sound propagation method and is fully compliant with ISO 9613 and the sound power level (PWL) estimation for a road segment, as suggested in the ASJ Model-1998 that is based on PWLs. Due to that model’s selection of two pavement types, such as asphalt or concrete pavement, an unacceptable traffic noise prediction is made in cases where the road surface is different from that on which the model is based. In order to address this problem, several road surface types are categorized, and the PWL of each surface type is determined and modeled by measuring the noise levels obtained from newly developed methods. An evaluation of the traffic noise prediction model using field measurements finds good agreement between predicted and measured noise levels.
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Tack coat application rates and testing conditions differ among nations and construction conditions because various tack coat materials are available. In this study, newer materials are optimized for addition to porous asphalt pavements... more
Tack coat application rates and testing conditions differ among nations and construction conditions because various tack coat materials are available. In this study, newer materials are optimized for addition to porous asphalt pavements exposed to torrential rainfall, which is common in South Korea. Interface shear strength (ISS) tests are used to define the optimum application rates (OARs) of tack coat materials generally used in South Korea, by reference to the Korean Design Standard (KDS), the Korean Construction Standard (KCS), and features of pavement construction and bonding. We performed ISS tests using asphalt mixtures with porosities of 3, 5, and 7% to explore the effect of porosity on shear strength. The ISSs associated with varying tack coat proportions were earlier determined by creating polynomial regression equations. Here, we develop a predictive model using a non-linear function to estimate the OAR of tack coat and compare our approach with the earlier polynomial reg...
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Here, we develop a model predicting the dynamic moduli of hot-mix asphalt/concrete using the extended Kalman filter (EKF) algorithm and draw frequency-domain master curves. Discrete dynamic moduli were obtained via impact resonance tests... more
Here, we develop a model predicting the dynamic moduli of hot-mix asphalt/concrete using the extended Kalman filter (EKF) algorithm and draw frequency-domain master curves. Discrete dynamic moduli were obtained via impact resonance tests (IRTs) on linear viscoelastic (LVE) asphalt at 20, 30, 35, 40, and 50°C. Typically, viscoelastic characteristics have been used to derive asphalt dynamic moduli; compressive frequency sweep tests at different frequencies (Hz) and temperatures are employed to this end. We compared IRT-derived viscoelastic master curves obtained via compressive frequency sweep testing to those derived using the EKF algorithm, which employs a nonlinear sigmoidal curve and a Taylor series to explore the viscoelastic function. The model reduced errors at both low and high frequencies by correcting the coefficients of the master curve. Furthermore, the predictive model effectively estimated dynamic moduli at various frequencies, and also root-mean-square errors (RMSEs) wh...
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Due to the growing number of vehicles using the national road networks that link major urban centers, traffic noise is becoming a major issue in relation to the transportation system. Thus, it is important to determine noise model... more
Due to the growing number of vehicles using the national road networks that link major urban centers, traffic noise is becoming a major issue in relation to the transportation system. Thus, it is important to determine noise model parameters to predict road traffic noise levels as part of an environmental assessment, according to traffic volume and pavement surface type. To determine the parameters of a noise prediction model, statistical pass-by and close proximity tests are required. This paper provides a parameter determination procedure for noise prediction models through an adaptive particle filter (PF) algorithm, based on using a weigh-in-motion system, which obtains vehicle velocities and types, as well as step-up microphones, which measure the combined noises emitted by various vehicle types. Finally, an evaluation of the adaptive noise parameter determination algorithm was carried out to assess the agreement between predictions and measurements.
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PURPOSES : The purpose of this study is to eliminate the noise of the vehicle after measuring the friction noise obtained from the NCPX (Noble Close ProXimity) method. The pure friction noise between the tire and road pavement could be... more
PURPOSES : The purpose of this study is to eliminate the noise of the vehicle after measuring the friction noise obtained from the NCPX (Noble Close ProXimity) method. The pure friction noise between the tire and road pavement could be determined from filtering the compositeness of sound and the influence of the vehicle noise. METHODS: The noise magnitude could be determined by analyzing the sound pressure level (SPL) and sound power level (PWL) along with the noise frequency of a FFT (Fast Fourier Transform) analysis as well as CPB (Constant Percentage Bandwidth) analysis. RESULTS: When the test for measuring the friction noise originated somewhere between tire and road pavement is performed with NCPX method, it must be fulfilled by attaching the surface microphone near the tire. In this condition, the surface microphone can measure the friction noise occurred at between tire and pavement, the chassis noise from the engine and power transfer units, the fluctuating aerodynamic noise, and the turbulence noise directly affected to the surface microphone. By using the NCPX method, the noise occurred at the vehicle must be eliminated for measuring the friction noise between tire and pavement from the traffic noise. CONCLUSIONS: The vehicle`s testing engine noise depends on the vehicle and road types. The effect of vehicle`s engine noise is less than the friction noise occurred at between tire and pavement at less than 1% effect.
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PURPOSES : The objective of this study is to provide for the overall SPL (Sound Pressure Level) prediction model by using the NCPX (Noble Close Proximity) measurement method in terms of regression equations. METHODS: Many methods can be... more
PURPOSES : The objective of this study is to provide for the overall SPL (Sound Pressure Level) prediction model by using the NCPX (Noble Close Proximity) measurement method in terms of regression equations. METHODS: Many methods can be used to measure the traffic noise. However, NCPX measurement can powerfully measure the friction noise originated somewhere between tire and pavement by attaching the microphone at the proximity location of tire. The overall SPL(Sound Pressure Level) calculated by NCPX method depends on the vehicle speed, and the basic equation form of the prediction model for overall SPL was used, according to the previous studies (Bloemhof, 1986; Cho and Mun, 2008a; Cho and Mun, 2008b; Cho and Mun, 2008c). RESULTS : After developing the prediction model, the prediction model was verified by the correlation analysis and RMSE (Root Mean Squared Error). Furthermore, the correlation was resulted in good agreement. CONCLUSIONS: If the polynomial overall SPL prediction model can be used, the special cautions are required in terms of considering the interpolation points between vehicle speeds as well as overall SPLs.
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... consists of Steps 1 to 5, is shown in Figure 1. The algorithm parameters are specified in Step 1, as follows: the har-mony memory size (HMS) is initialized as the number of solution vectors in har-mony memory (HM); the harmony memory... more
... consists of Steps 1 to 5, is shown in Figure 1. The algorithm parameters are specified in Step 1, as follows: the har-mony memory size (HMS) is initialized as the number of solution vectors in har-mony memory (HM); the harmony memory considering rate (HMCR, between 0 ...