@article{kim_lee_se_el-haggan_2008, title={Determination of price reduction factors for density-deficient asphalt pavements}, volume={36}, DOI={10.1520/jte101460}, abstractNote={Abstract
               This paper presents the research undertaken for the development of price reduction factors for density-deficient asphalt pavements. Performance characteristics included in this study are fatigue cracking and rutting. The following laboratory tests were performed on two North Carolina Superpave mixtures with varying air void contents: (1) axial compression dynamic modulus tests for modulus determination; (2) indirect tension tests for fatigue performance evaluation; (3) triaxial repeated load permanent deformation tests for rutting evaluation; and (4) accelerated pavement tests on laboratory pavement slabs for fatigue and rutting evaluation using the third-scale Model Mobile Loading Simulator (MMLS3). Air void models for the dynamic modulus, fatigue cracking, and rutting were developed using the laboratory test data. These models and the results from the MMLS3 testing were used to develop the price reduction factors for density-deficient asphalt mixtures. In order to determine the effect of deficient density of hot-mix asphalt (HMA) on the performance of asphalt pavement as a system, a computer program called AP4 (Asphalt Pavement Performance Prediction Program) was developed. The algorithm adopted in AP4 for the damage calculation is based on the incremental damage concept and is very similar to that used in the National Cooperative Highway Research Program (NCHRP) 1-37A Mechanistic-Empirical Pavement Design Guide. This program allows the determination of the service life for fatigue cracking and rutting based on the inputs of air void contents in all the HMA layers. Case studies of five density-deficient pavements were conducted, and the price reduction factors were determined.}, number={4}, journal={Journal of Testing and Evaluation}, author={Kim, Y. R. and Lee, S. J. and Se, Y. and El-Haggan, O.}, year={2008}, pages={335–344} }
 @article{seo_kim_2008, title={Using Acoustic Emission to Monitor Fatigue Damage and Healing in Asphalt Concrete}, volume={12}, ISSN={["1976-3808"]}, DOI={10.1007/s12205-008-0237-3}, number={4}, journal={KSCE JOURNAL OF CIVIL ENGINEERING}, author={Seo, Youngguk and Kim, Y. Richard}, year={2008}, month={Jul}, pages={237–243} }
 @article{kim_seo_king_momen_2004, title={Dynamic modulus testing of asphalt concrete in indirect tension mode}, ISBN={["0-309-09485-2"]}, ISSN={["0361-1981"]}, DOI={10.3141/1891-19}, abstractNote={ This study presents the results from an analytical and experimental study on the dynamic modulus testing of hot-mix asphalt using the indirect tension (IDT) mode. An analytical solution for the dynamic modulus in the IDT mode was developed with the use of linear viscoelasticity. To verify the analytical solution, temperature and frequency sweep tests were conducted on 12 asphalt mixtures commonly used in North Carolina; both axial compression and IDT test methods were used. A modified dynamic modulus test protocol is introduced to reduce the required testing time by using more frequencies and fewer temperatures on the basis of the time-temperature superposition principle. A comparison of results from the axial compression and IDT test methods shows that the dynamic modulus master curves and shift factors derived from the two methods are in good agreement. It also was found that Poisson's ratio was a weak function of the loading frequency; its effect on the phase angle master curve is discussed. }, number={1891}, journal={BITUMINOUS PAVING MIXTURES 2004}, author={Kim, YR and Seo, Y and King, M and Momen, M}, year={2004}, pages={163–173} }
 @article{seo_kim_witczak_bonaquist_2002, title={Application of digital image correlation method to mechanical testing of asphalt-aggregate mixtures}, ISBN={["0-309-07714-1"]}, ISSN={["0361-1981"]}, DOI={10.3141/1789-18}, abstractNote={ The digital image correlation (DIC) method, a noncontact, full-field displacement measurement technique, has been applied to mechanical testing of asphalt concrete. A single couple charged device camera acquires images of an area of interest from a specimen in the undeformed and deformed states. These images are correlated to determine deformations, and advanced mathematical procedures are applied to these deformations to calculate strains. To verify the DIC measurements, vertical displacements for the middle and bottom sections of a specimen subjected to monotonic tension are compared with conventional linear variable differential transformer measurements. A series of DIC images captured during the monotonic and cyclic tests visualizes the evolution of the failure zone (i.e., the fracture process zone) at the crack tip. Also, it is demonstrated that the full-field measurement and post-processing nature of DIC allows a more accurate determination of the stress-strain behavior of the fracture process zone. The applicability of this method to a cylindrical specimen with a curved surface is also investigated by testing a 75-mm-diameter cylindrical specimen. Finally, the DIC method is extended to cyclic testing of asphalt mixtures with the aid of a synchronized image acquisition technique. }, number={1789}, journal={BITUMINOUS PAVING MIXTURES 2002}, author={Seo, Y and Kim, YR and Witczak, MW and Bonaquist, R}, year={2002}, pages={162–172} }