@article{rashetnia_kusam_yadav_pour-ghaz_tayebali_2022, title={Quantifying moisture damage in asphalt concrete using axisymmetric flexural vibration technique}, volume={23}, ISSN={["1477-268X"]}, DOI={10.1080/10298436.2020.1757671}, abstractNote={ABSTRACT The Tensile Strength Ratio (TSR) test is commonly used to quantify the moisture susceptibility of asphalt mixtures. This test method is based on the indirect tensile strength, which is not a fundamental property and hence cannot be used in the asphalt mixture design process. Therefore, alternative test methods that use a fundamental property to quantify moisture sensitivity of asphalt mixtures are needed. This study investigates if the linear impact resonance shift and frequency spectrum bandwidth changes measured using Axisymmetric Flexural Vibration (AFV) technique can be used to quantify moisture damage. This test enables calculation of the dynamic elastic modulus of the disk, based on measured resonance frequency as well as quantification of vibration energy dissipation in the specimens based on the change in bandwidth of frequency spectrum. AFV test is used to quantify moisture damage susceptibility of asphalt mixture specimens with different moisture conditioning levels and different mixture designs. The results of the AFV test are compared with the TSR test. Also, the sensitivity of the AFV test to quantify the effect of thixotropic aging due to storage and temperature are discussed. The results show that the AFV technique can successfully quantify moisture damage and the effect of aging and temperature change.}, number={3}, journal={INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING}, author={Rashetnia, Reza and Kusam, Abhilash and Yadav, Shivpal and Pour-Ghaz, Mohammad and Tayebali, Akhtarhusein}, year={2022}, month={Feb}, pages={523–535} }
 @article{rashetnia_pour-ghaz_2021, title={Deep learning surrogate interacting Markov chain Monte Carlo based full wave inversion scheme for properties of materials quantification}, volume={497}, ISSN={["1095-8568"]}, DOI={10.1016/j.jsv.2021.115934}, abstractNote={Full Wave Inversion (FWI) imaging scheme has many applications in engineering, geoscience and medical sciences. In this paper, a surrogate deep learning FWI approach is presented to quantify properties of materials using stress waves. Such inverse problems, in general, are ill-posed and nonconvex, especially in cases where the solutions exhibit shocks, heterogeneity and discontinuities. The proposed approach is proven efficient to obtain global minima responses in these cases. This approach is trained based on random sampled sets of material properties and sampled trials around local minima, therefore, it requires a forward simulation can handle high heterogeneity, discontinuities and large gradients. High resolution Kurganov–Tadmor (KT) central finite volume method is used as forward wave propagation operator. Using the proposed framework, material properties of 2D media are quantified for several different situations. The results demonstrate the feasibility of the proposed method for estimating mechanical properties of materials with high accuracy using deep learning approaches.}, journal={JOURNAL OF SOUND AND VIBRATION}, author={Rashetnia, Reza and Pour-Ghaz, Mohammad}, year={2021}, month={Apr} }
 @article{mohammadian_rashetnia_lucier_seracino_pour-ghaz_2019, title={Numerical simulation and experimental corroboration of galvanic corrosion of mild steel in synthetic concrete pore solution}, volume={103}, ISSN={["1873-393X"]}, DOI={10.1016/j.cemconcomp.2019.04.027}, abstractNote={Corrosion of reinforcing steel in concrete is one of the most prevalent deterioration mechanisms affecting reinforced concrete structures. While there have been significant advances in modeling the initiation stage of corrosion, corrosion kinetic models for predicting the rate of corrosion after depassivation of steel are scarce, and models with experimental corroboration under controlled experimental conditions are virtually nonexistent. Furthermore, the sensitivity of corrosion kinetic models to the uncertainty of their input parameters is not understood. The objective of the present work is to model active corrosion of steel in synthetic solution, experimentally corroborate the modeling approach under controlled conditions, and study the effect of uncertainty of the input parameters on the model predictions. To this end, a two-dimensional finite element method is used to solve the coupled system of Poisson-Nernst-Planck (PNP) equations subjected to electroneutrality constraint. To corroborate the modeling approach, the results of computations are compared against one-dimensional and two-dimensional galvanic corrosion of stainless/carbon steel in dilute and non-dilute NaCl electrolytes as well as two synthetic concrete pore solutions. The modeling parameters, including electrode polarization behaviors and electrolyte properties, are obtained experimentally. Monte Carlo simulations are used to understand the effect of uncertainty of polarization parameters on the predicted corrosion rate.}, journal={CEMENT & CONCRETE COMPOSITES}, author={Mohammadian, Armita and Rashetnia, Reza and Lucier, Gregory and Seracino, Rudolf and Pour-Ghaz, Mohammad}, year={2019}, month={Oct}, pages={263–278} }
 @article{rashetnia_ghasemzadeh_hallaji_pour-ghaz_2018, title={Quantifying prestressing force loss due to corrosion from dynamic structural response}, volume={433}, ISSN={["1095-8568"]}, DOI={10.1016/j.jsv.2018.07.012}, abstractNote={In prestressed concrete structures, corrosion of prestressing strands is a major durability concern. In advanced stages, corrosion may result in the rupture of strands. At early stages, corrosion of strands results in microcracking, deterioration of bond between strands and concrete, and therefore, in the loss of prestressing force. These effects, in turn, result in the change of dynamic response of prestressed elements. In this paper, we investigate whether the prestressing force of prestressed beams can be estimated indirectly using dynamic vibration test. For this purpose, six prestressed concrete beams were manufactured. Two beams were kept as control, two beams were corroded along the entire length of the strand, and two beams were corroded along one-third of the strand length. The induced accelerated corrosion was monitored by corrosion current measurements and passive acoustic emission. Two system identification approaches were developed where both utilize the free vibration response of an Euler-Bernoulli beam to estimate prestressing force of strands. Due to the ill-possedness of the identification problems and the presence of random and systematic errors in the experiment, Tikhonov regularization method was used. Finally, results were compared with analytical solution of vibration of a simply supported beam with external compressive force. It was concluded that using dynamic vibration of prestressed concrete beams and using indirect estimation approaches, it is possible to quantify the loss of prestressing force due to corrosion.}, journal={JOURNAL OF SOUND AND VIBRATION}, author={Rashetnia, Reza and Ghasemzadeh, Farnam and Hallaji, Milad and Pour-Ghaz, Mohammad}, year={2018}, month={Oct}, pages={129–137} }
 @article{smyl_rashetnia_seppanen_pour-ghaz_2017, title={Can Electrical Resistance Tomography be used for imaging unsaturated moisture flow in cement-based materials with discrete cracks?}, volume={91}, ISSN={["1873-3948"]}, DOI={10.1016/j.cemconres.2016.10.009}, abstractNote={Previously, it has been shown that Electrical Resistance Tomography (ERT) can be used for monitoring moisture flow in undamaged cement-based materials. In this work, we investigate whether ERT could be used for imaging three-dimensional (3D) unsaturated moisture flow in cement-based materials that contain discrete cracks. Novel computational methods based on the so-called absolute imaging framework are developed and used in ERT image reconstructions, aiming at a better tolerance of the reconstructed images with respect to the complexity of the conductivity distribution in cracked material. ERT is first tested using specimens with physically simulated cracks of known geometries, and corroborated with numerical simulations of unsaturated moisture flow. Next, specimens with loading-induced cracks are imaged; here, ERT reconstructions are evaluated qualitatively based on visual observations and known properties of unsaturated moisture flow. Results indicate that ERT is a viable method of visualizing 3D unsaturated moisture flow in cement-based materials with discrete cracks.}, journal={CEMENT AND CONCRETE RESEARCH}, author={Smyl, Danny and Rashetnia, Reza and Seppanen, Aku and Pour-Ghaz, Mohammad}, year={2017}, month={Jan}, pages={61–72} }
 @article{rashetnia_hallaji_smyl_seppanen_pour-ghaz_2017, title={Detection and localization of changes in two-dimensional temperature distributions by electrical resistance tomography}, volume={26}, ISSN={["1361-665X"]}, DOI={10.1088/1361-665x/aa8f75}, abstractNote={This paper studies the feasibility of applying electrical resistance tomography (ERT) to detect changes in two-dimensional (2D) temperature distributions with potential applications in sensor development. The proposed sensor consists of a thin layer of porous metal film manufactured by spraying colloidal copper paint to a solid surface. A change of the temperature distribution on the surface changes the 2D distributed electrical conductivity of the metal film. The change of the electrical conductivity is localized and quantified with ERT, and further, to convert the estimated conductivity change of the sensor to temperature change, an experimentally developed model is used. The proposed temperature sensor is evaluated experimentally by applying it to a polymeric substrate, and exposing it to known temperature changes using heat sources of different shapes. The results demonstrate that the proposed sensor is capable of detecting and localizing temperature changes, and provides at least qualitative information on the magnitude of the temperature change.}, number={11}, journal={SMART MATERIALS AND STRUCTURES}, author={Rashetnia, Reza and Hallaji, Milad and Smyl, Danny and Seppanen, Aku and Pour-Ghaz, Mohammad}, year={2017}, month={Nov} }
 @article{ghasemzadeh_rashetnia_smyl_pour-ghaz_2016, title={A comparison of methods to evaluate mass transport in damaged mortar}, volume={70}, ISSN={["1873-393X"]}, DOI={10.1016/j.cemconcomp.2016.03.007}, abstractNote={The service life of reinforced concrete (RC) structures is directly influenced by the transport properties of concrete. These transport properties are adversely affected by the presence of cracks. Therefore, for accurate service life estimation of RC structures the effect of cracks on mass transport needs to be understood and quantified. To quantify the effect of cracks, different measurement methods have been developed. In this paper, we compare different mass transport measurement methods for quantifying the effect of damage, and investigate which method is more sensitive and provides the most information on the effect of damage. In this work, damage was induced by freeze-thaw in mortar specimens. Mass transport properties were measured using electrical resistivity, rapid chloride permeability, sorptivity, drying, air permeability, water permeability, and desorption isotherm. The results indicate that the measured effect of damage depends on the mechanisms of transport used in the measurement technique, and therefore, different measurement techniques do not necessarily provide the same measure of the effect of damage. The water and air permeability are comparatively more sensitive to the presence of damage.}, journal={CEMENT & CONCRETE COMPOSITES}, author={Ghasemzadeh, Farnam and Rashetnia, Reza and Smyl, Danny and Pour-Ghaz, Mohammad}, year={2016}, month={Jul}, pages={119–129} }
 @article{rashetnia_ghasemzadeh_pour-ghaz_2016, title={The Consequences of Material Nonlinearity on the Axisymmetric Flexural Vibration Measurements for Estimating the Dynamic Elastic Modulus of Damaged Cement Based Materials}, volume={14}, ISSN={["1347-3913"]}, DOI={10.3151/jact.14.287}, abstractNote={Elastic modulus measurements are often required to evaluate the structural performance or to estimate the damage in cement-based materials. The axisymmetric flexural vibration (AFV) of a thick circular disk is a test method that can be used to estimate the dynamic elastic modulus of cement-based materials. Cement-based materials are inherently nonlinear materials and their nonlinearity increases with damage. The main objectives of this paper are to investigate the consequences of material nonlinearity on the AFV measurements, and to understand the implications of the change of material nonlinearity with damage on these measurements. In this work, experimental measurements are performed on mortar specimens damaged by freeze-thaw. Acoustic emission is used as a benchmark method to monitor and quantify the damage.}, number={6}, journal={JOURNAL OF ADVANCED CONCRETE TECHNOLOGY}, author={Rashetnia, Reza and Ghasemzadeh, Farnam and Pour-Ghaz, Mohammad}, year={2016}, month={Jun}, pages={287–298} }
 @inproceedings{rashetnia_pour-ghaz_2015, title={Estimating the mechanical properties of layered media using ultrasonics: Numerical study with high resolution wave propagation}, DOI={10.12783/shm2015/318}, abstractNote={Estimating the mechanical properties of layered media using ultrasonics is challenging due to the ill-posed, nonconvex, and nonlinear nature of the problem. To address this challenge, we use Kurganov Tadmor (KT) central scheme for the forward model of wave propagation since it provides a robust model for layered media with sharp boundaries. KT also minimizes numerical challenges such as dispersion error propagation. In this study, we consider a one-dimensional stress wave propagation problem. To solve the inverse problem of estimating the mechanical properties, we utilize non-heuristic random search algorithm with surrogate model. The random search algorithm performs a global search within the feasible search area, and the surrogate model applies an artificial Neural Network and a genetic algorithm to produce optimal estimations. This method also decreases the computational cost. The results show that this method can be successfully used to estimate the mechanical properties of the layered one-dimensional media. doi: 10.12783/SHM2015/318}, booktitle={Structural health monitoring 2015: system reliability for verification and implementation, vols. 1 and 2}, author={Rashetnia, R. and Pour-Ghaz, M.}, year={2015}, pages={2559–2566} }