@article{park_pour-ghaz_2019, title={Another Look at the Abrasion Resistance of Concrete}, volume={8}, ISSN={["2165-3984"]}, DOI={10.1520/ACEM20180159}, abstractNote={Abstract}, number={1}, journal={ADVANCES IN CIVIL ENGINEERING MATERIALS}, author={Park, Sungwoo and Pour-Ghaz, Mohammad}, year={2019}, pages={423–434} }
 @article{park_kim_park_2005, title={Assessment of pavement layer condition with use of multiload-level failing weight deflectometer deflections}, ISBN={["0-309-09377-5"]}, ISSN={["0361-1981"]}, DOI={10.3141/1905-13}, abstractNote={A condition assessment procedure for pavement layers that uses multiload-level falling weight deflectometer (FWD) deflections is presented. A dynamic finite element program that incorporates a stress-dependent soil model was used to generate the synthetic deflection database. On the basis of the data in this database, the relationships between surface deflections and critical pavement responses, such as the stresses and strains in each layer, have been established. The FWD deflection data, distress survey results, temperature, and laboratory testing results used to develop this procedure were collected from the Long-Term Pavement Performance project database. Research efforts also focused on the effect of the FWD load level on the condition assessment procedure. The results indicate that the proposed procedure can estimate the asphalt concrete (AC), base, and subgrade layer conditions. The AC layer modulus and the tensile strain at the bottom of the AC layer were found to be better indicators of the condition of the AC layer than the deflection basin parameter. It was also found that the structurally adjusted base damage index and base curvature index were good indicators for prediction of the stiffness characteristics of the aggregate base and subgrade, respectively. An FWD test with a load of 71.2 kN or less does not improve the accuracy of this procedure. The results from the study of the nonlinear behavior of a pavement structure indicate that the deflection ratio obtained from multiload-level deflections can predict the type and quality of the base and subgrade materials.}, number={1905}, journal={PAVEMENT REHABILITATION, STRENGTH AND DEFORMATION CHARACTERISTICS, AND SURFACE PROPERTIES 2005}, author={Park, HM and Kim, YR and Park, SW}, year={2005}, pages={107–116} }
 @inbook{park_kim_park_2002, title={Temperature correction of multiload-level failing weight deflectometer deflections}, ISBN={030907732X}, DOI={10.3141/1806-01}, abstractNote={ A new temperature correction procedure was developed for multiload-level falling weight deflectometer (FWD) deflections for flexible pavements in North Carolina. In this procedure, temperature correction factors were dependent on the radial offset distance from the FWD load plate. Temperature and FWD multiload-level deflection data used in developing this procedure were collected from 11 pavements in three different climatic regions of North Carolina. The effect of the FWD load level on this temperature correction procedure was investigated. Research efforts focused on improving the accuracy of the current temperature correction procedure of the North Carolina Department of Transportation. The measured deflection and temperature data were also used to validate the long-term pavement performance (LTPP) temperature correction procedure. It was found that the effective pavement temperature prediction algorithm in the LTPP procedure is relatively accurate and that the temperature-deflection correction procedure undercorrects the deflections at higher temperatures in pavements with an asphalt concrete layer thicker than 242 mm. The main reason for this deficiency is that the LTPP procedure was developed from the national database and cannot fully consider the local variation in mixture characteristics. }, number={1806}, booktitle={Assessing and evaluating pavements, 2002}, publisher={Washington, D.C.: National Academy Press}, author={Park, H. M. and Kim, Y. R. and Park, S.}, year={2002}, pages={3–8} }
 @article{park_kim_2001, title={Fitting prony-series viscoelastic models with power-law presmoothing}, volume={13}, DOI={10.1061/(asce)0899-1561(2001)13:1(26)}, abstractNote={An efficient method of fitting Prony-series models to viscoelastic experimental data with power-law presmoothing is presented. A direct fitting of a Prony-series function to experimental data without appropriate presmoothing is difficult when the data have significant variance. A power-law series comprising multiple power-law terms is found capable of portraying a globally smooth, broadband viscoelastic behavior with minimal impact from local variance in the data. However, from a computational point of view, a Prony series representation is preferred to a power-law series representation because of the computational efficiency associated with the exponential basis functions of a Prony series. In this paper, a procedure involving presmoothing of experimental data via power-law-series representation followed by fitting of a Prony-series model to the presmoothed data is discussed and illustrated. Discussion focuses on how experimental data with significant variance can be effectively presmoothed through power...}, number={1}, journal={Journal of Materials in Civil Engineering}, author={Park, S. W. and Kim, Y. R.}, year={2001}, pages={26–32} }
 @article{park_kim_lee_1999, title={Fracture toughness for microcracking in a viscoelastic particulate composite}, volume={125}, DOI={10.1061/(ASCE)0733-9399(1999)125:6(722)}, abstractNote={Fracture toughness for microcracking in a viscoelastic particulate composite is derived theoretically from the relationship between a continuum damage model and a micromechanical model. The continuum model presented by Park and colleagues (1996) and the micromechanical model presented by Schapery (1986), which account for viscoelasticity and growing damage, are reviewed and compared in this note. The condition for local microcrack growth is linked to the evolution law for damage growth in the homogenized continuum. Local microcrack growth is governed by an energy-based fracture criterion. Damage growth in the continuum is described by a phenomenological evolution law determined from an experiment. The resulting fracture toughness for asphalt concrete decreases rapidly with loading duration.}, number={6}, journal={Journal of Engineering Mechanics}, author={Park, S. W. and Kim, Y. R. and Lee, H. J.}, year={1999}, pages={722–725} }
 @article{park_kim_1999, title={Interconversion between relaxation modulus and creep compliance for viscoelastic solids}, volume={11}, DOI={10.1061/(ASCE)0899-1561(1999)11:1(76)}, abstractNote={Methods of interconversion between relaxation modulus and creep compliance for linear viscoelastic materials are discussed and illustrated using data from asphalt concrete. Existing methods of approximate interconversion are reviewed and compared for their approximating schemes. A new approximate interconversion scheme that uses the local log-log slope of the source function is introduced. The new scheme is based on the concept of equivalent time determined by rescaling the physical time. The rescaling factor, which can be interpreted as a shift factor on a logarithmic time axis, is dictated by the local slope of the source function on log-log scales. The unknown target function at a given time is obtained by taking the reciprocal of the source function evaluated at an equivalent time. Although the method is developed using a mathematical relationship based on the power-law representations of relaxation modulus and creep compliance, the method is not limited to material functions characterized by power-laws but can be applied to general, non-power-law material functions as long as the relevant material behaviors are broadband and smooth on logarithmic scales. The new method renders good results especially when the log-log slope of the source function varies smoothly with logarithmic time.}, number={1}, journal={Journal of Materials in Civil Engineering}, author={Park, S. W. and Kim, Y. R.}, year={1999}, pages={76–82} }
 @article{park_kim_1998, title={Analysis of layered viscoelastic system with transient temperatures}, volume={124}, DOI={10.1061/(asce)0733-9399(1998)124:2(223)}, abstractNote={A method for quasi-static analysis of a layered viscoelastic system with transient temperatures is presented. First, the response, displacements and stresses of the system to the unit step load with a constant temperature is obtained from the corresponding elastic solution. The response to a transient load is then obtained through a linear superposition integral using the unit response as the kernel function. The effects of spatially homogeneous, transient temperature on the mechanical response of the system are taken into account through the time-temperature superposition principle. The method is not based on the Laplace transform-based correspondence principle and no transform-inversion process is required. An illustration of the method is presented through an analysis of the stresses and the displacements in a three-layer, elastic-viscoelastic composite half-space subjected to a distributed surface load under different temperature conditions.}, number={2}, journal={Journal of Engineering Mechanics}, author={Park, S. W. and Kim, Y. R.}, year={1998}, pages={223–231} }
 @inbook{shao_park_kim_1997, title={A simplified procedure for prediction of asphalt pavement subsurface temperatures based on heat transfer theories}, ISBN={0309059747}, DOI={10.3141/1568-14}, abstractNote={ Surface deflection measurements and backcalculation of layer moduli in flexible pavements are significantly affected by the temperature of the asphalt concrete (AC) layer. Correction of deflections or backcalculated moduli to a reference temperature requires determination of an effective temperature of the AC layer. For routine deflection testing and analysis in state highway agencies, it is preferable, from a practical point of view, to use a nondestructive prediction method for determining the effective AC layer temperature instead of measuring the temperature directly from a small hole drilled into the AC layer. A simplified procedure to predict asphalt pavement subsurface temperatures is presented. The procedure is based on fundamental principles of heat transfer and uses the surface temperature history since yesterday morning to predict the AC layer mid-depth temperature at the time of falling weight deflectometer (FWD) testing today. The surface temperature history is determined using yesterday’s maximum air temperature and cloud condition, the minimum air temperature of today’s morning, and surface temperatures measured during FWD tests. FWD tests and temperature measurements have been conducted on seven pavement sections with varying structural designs located in three different climatic regions of North Carolina. The field temperature records from these pavements have provided values of pavement thermal parameters and coefficients in temperature functions that are needed in the prediction procedure. A set of verification results are presented using examples with different climatic regions, changing AC layer thicknesses, and varying weather patterns in different seasons. }, number={1568}, booktitle={Pavement rehabilitation and design}, publisher={Washington, DC: National Academy Press}, author={Shao, L. and Park, S. and Kim, Y. R.}, year={1997}, pages={114–123} }
 @article{park_schapery_1997, title={A viscoelastic constitutive model for particulate composites with growing damage}, volume={34}, ISSN={["0020-7683"]}, DOI={10.1016/S0020-7683(96)00066-2}, abstractNote={A mechanical model which describes time-and temperature-dependent deformation behavior of particulate composites with changing microstructure, including growing damage, is described and then verified by experimental study of a viscoelastic filled elastomer. An existing constitutive model, which is based upon thermodynamics of irreversible processes with internal state variables, is first reviewed and then used to describe the mechanical behavior of elastic and viscoelastic media with changing microstructure. A rate-type equation is successfully employed in describing the evolution of microstructural changes, which are believed here to be primarily microcracking. An elastic-viscoelastic correspondence principle and the time-temperature superposition principle are used in modeling effects of the material's intrinsic viscoelasticity and the effects of temperature changes. Laboratory tests of the stress and dilatation responses of uniaxial test specimens under controlled monotonically increasing axial extension and constant confining pressure at different temperatures were performed. The effects of strain level, strain rate, confining pressure, and temperature on the stress and dilatation are described and compared to the theoretical model.}, number={8}, journal={INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES}, author={Park, SW and Schapery, RA}, year={1997}, month={Mar}, pages={931–947} }
 @inbook{park_kim_1997, title={Temperature correction of backcalculated moduli and deflections using linear viscoelasticity and time-temperature superposition}, ISBN={0309061539}, DOI={10.3141/1570-13}, abstractNote={ New analytical procedures for temperature correction of backcalculated asphalt concrete moduli and surface deflections were developed based on the theory of linear viscoelasticity and the time-temperature superposition principle and verified using falling weight deflectometer data and field temperature measurements. The new correction procedures explicitly utilize the thermorheological properties of the asphalt mixture. The resulting temperature-modulus correction factors depend only on the relaxation modulus and time-temperature shift factor of the mixture. The temperature-deflection correction factor depends on both the material properties and the layer thicknesses of the pavement section. Emphasis has been placed on the analytical description of the mixture’s thermoviscoelasticity responsible for temperature effects on mixture modulus and pavement deflection. A mechanistic framework for dealing with temperature correction problems for asphalt pavement has been introduced. }, number={1570}, booktitle={Pavement research issues}, publisher={Washington, DC: National Academy Press}, author={Park, S. and Kim, Y. R.}, year={1997}, pages={108–117} }