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Lubinda F Walubita - One of the best experts on this subject based on the ideXlab platform.

  • comparison of fracture cracking parameters from Monotonic Loading tests indirect tension and Monotonic overlay tester tests
    Transportation Research Record, 2016
    Co-Authors: Sang Ick Lee, Abu N M Faruk, Lubinda F Walubita
    Abstract:

    Cracking is one of the major structural distresses that occur in hot-mix asphalt (HMA) pavements and is undesirable. Cracking often leads to costly maintenance and rehabilitation activities. Various laboratory test methods, including the indirect tension (IDT) test, semicircular bend test, Texas Overlay Test (OT), and bending beam fatigue test, are typically used to characterize and quantify the resistance of HMA to cracking. Recently, the OT test in Monotonic Loading configuration was explored as a supplement or surrogate to the traditional repeated Loading OT test for evaluating the cracking resistance potential of HMA mixes in the laboratory. The basic analysis parameters from the Monotonic OT test include the tensile strength, failure tensile strain, fracture energy (FE), and FE index, which are essentially the same fracture parameters obtainable from the IDT test. In this study, the crack resistance potentials of 15 different HMA mixes were comparatively evaluated with two Monotonic Loading tests: th...

  • using the fracture energy index concept to characterize the hma cracking resistance potential under Monotonic crack testing
    International journal of pavement research and technology, 2014
    Co-Authors: Abu N M Faruk, Xiaodi Hu, Yuly Lopez, Lubinda F Walubita
    Abstract:

    In this study, the concept of the Fracture Energy (FE) Index was explored as a fracture parameter to characterize and quantify the cracking resistance potential of hot-mix asphalt (HMA) mixes subjected to Monotonic Loading in the laboratory. Mathematically, the FE Index was defined as a parametric ratio of the total FE to the HMA tensile strength and tensile strain at peak failure load per unit crack length. The concept was put into practice by testing commonly used Texas HMA mixes, with cracking resistance potential ranging from poor to good, under the Overlay Tester -Monotonic Loading setup (OT(subscript M)) along with two other more commonly used Monotonic Loading tests, namely: the Indirect Tensile Test (IDT) and the Semi-Circular Bending Test (SCB). Corresponding results indicated that the FE Index has promising potential to be used as a fracture parameter to discriminate and rank the cracking resistance potential of HMA mixes in the laboratory. As expected of Monotonic Loading crack tests, variability was within acceptable tolerances, except for the SCB that exhibited high variability, particularly at higher asphalt-binder contents. The FE Index also exhibited sensitivity to HMA mix-design variables such as the asphalt-binder content, particulalry for the OT(subscript M) and IDT tests. Overall, the OT(subscript M) and the IDT tests exhibited supperiority over the SCB test and would readily serve as surrogate crack tests for routine HMA mix-design and screening in the laboratory. For room temperature testing at 25°C, the SCB test appeared to be better suited for low asphalt-binder content mixes.

  • the overlay tester ot using the fracture energy index concept to analyze the ot Monotonic Loading test data
    Construction and Building Materials, 2013
    Co-Authors: Lubinda F Walubita, Abu N M Faruk, Allex E Alvarez, Tom Scullion
    Abstract:

    Abstract In this study, the concept of the Fracture Energy (FE) Index was explored as a fracture parameter to characterize and differentiate the cracking resistance potential of hot-mix asphalt (HMA) subjected to the Overlay Tester (OT) test under Monotonic Loading in the laboratory; denoted herein as the OT M test. Mathematically, the FE Index was derived and defined as a parametric ratio of the total FE to the HMA tensile strength and tensile strain at peak failure load per unit crack length under the OT Monotonic Loading testing, with a tensile Loading rate of 3.125 mm/min at a test temperature of 25 °C. Various HMA mixes, commonly used in Texas, with cracking resistance potential ranging from poor to good, were evaluated. Corresponding results indicated that the FE Index has promising potential to be used as a fracture parameter to discriminate and rank the cracking resistance potential of HMAs in the laboratory. While variability was generally within the acceptable tolerance (i.e., coefficient of variation of less than 30%), the FE Index exhibited sensitivity to the mix-design variables and was able to capture the effects of changes in the asphalt-binder content and temperature variations. Thus, this concept should be investigated further with more mixes and validated with field data for subsequent consideration in routine mix-designs and screening for adequate HMA cracking resistance in the laboratory.

Abu N M Faruk - One of the best experts on this subject based on the ideXlab platform.

  • comparison of fracture cracking parameters from Monotonic Loading tests indirect tension and Monotonic overlay tester tests
    Transportation Research Record, 2016
    Co-Authors: Sang Ick Lee, Abu N M Faruk, Lubinda F Walubita
    Abstract:

    Cracking is one of the major structural distresses that occur in hot-mix asphalt (HMA) pavements and is undesirable. Cracking often leads to costly maintenance and rehabilitation activities. Various laboratory test methods, including the indirect tension (IDT) test, semicircular bend test, Texas Overlay Test (OT), and bending beam fatigue test, are typically used to characterize and quantify the resistance of HMA to cracking. Recently, the OT test in Monotonic Loading configuration was explored as a supplement or surrogate to the traditional repeated Loading OT test for evaluating the cracking resistance potential of HMA mixes in the laboratory. The basic analysis parameters from the Monotonic OT test include the tensile strength, failure tensile strain, fracture energy (FE), and FE index, which are essentially the same fracture parameters obtainable from the IDT test. In this study, the crack resistance potentials of 15 different HMA mixes were comparatively evaluated with two Monotonic Loading tests: th...

  • using the fracture energy index concept to characterize the hma cracking resistance potential under Monotonic crack testing
    International journal of pavement research and technology, 2014
    Co-Authors: Abu N M Faruk, Xiaodi Hu, Yuly Lopez, Lubinda F Walubita
    Abstract:

    In this study, the concept of the Fracture Energy (FE) Index was explored as a fracture parameter to characterize and quantify the cracking resistance potential of hot-mix asphalt (HMA) mixes subjected to Monotonic Loading in the laboratory. Mathematically, the FE Index was defined as a parametric ratio of the total FE to the HMA tensile strength and tensile strain at peak failure load per unit crack length. The concept was put into practice by testing commonly used Texas HMA mixes, with cracking resistance potential ranging from poor to good, under the Overlay Tester -Monotonic Loading setup (OT(subscript M)) along with two other more commonly used Monotonic Loading tests, namely: the Indirect Tensile Test (IDT) and the Semi-Circular Bending Test (SCB). Corresponding results indicated that the FE Index has promising potential to be used as a fracture parameter to discriminate and rank the cracking resistance potential of HMA mixes in the laboratory. As expected of Monotonic Loading crack tests, variability was within acceptable tolerances, except for the SCB that exhibited high variability, particularly at higher asphalt-binder contents. The FE Index also exhibited sensitivity to HMA mix-design variables such as the asphalt-binder content, particulalry for the OT(subscript M) and IDT tests. Overall, the OT(subscript M) and the IDT tests exhibited supperiority over the SCB test and would readily serve as surrogate crack tests for routine HMA mix-design and screening in the laboratory. For room temperature testing at 25°C, the SCB test appeared to be better suited for low asphalt-binder content mixes.

  • the overlay tester ot using the fracture energy index concept to analyze the ot Monotonic Loading test data
    Construction and Building Materials, 2013
    Co-Authors: Lubinda F Walubita, Abu N M Faruk, Allex E Alvarez, Tom Scullion
    Abstract:

    Abstract In this study, the concept of the Fracture Energy (FE) Index was explored as a fracture parameter to characterize and differentiate the cracking resistance potential of hot-mix asphalt (HMA) subjected to the Overlay Tester (OT) test under Monotonic Loading in the laboratory; denoted herein as the OT M test. Mathematically, the FE Index was derived and defined as a parametric ratio of the total FE to the HMA tensile strength and tensile strain at peak failure load per unit crack length under the OT Monotonic Loading testing, with a tensile Loading rate of 3.125 mm/min at a test temperature of 25 °C. Various HMA mixes, commonly used in Texas, with cracking resistance potential ranging from poor to good, were evaluated. Corresponding results indicated that the FE Index has promising potential to be used as a fracture parameter to discriminate and rank the cracking resistance potential of HMAs in the laboratory. While variability was generally within the acceptable tolerance (i.e., coefficient of variation of less than 30%), the FE Index exhibited sensitivity to the mix-design variables and was able to capture the effects of changes in the asphalt-binder content and temperature variations. Thus, this concept should be investigated further with more mixes and validated with field data for subsequent consideration in routine mix-designs and screening for adequate HMA cracking resistance in the laboratory.

Tom Scullion - One of the best experts on this subject based on the ideXlab platform.

  • the overlay tester ot using the fracture energy index concept to analyze the ot Monotonic Loading test data
    Construction and Building Materials, 2013
    Co-Authors: Lubinda F Walubita, Abu N M Faruk, Allex E Alvarez, Tom Scullion
    Abstract:

    Abstract In this study, the concept of the Fracture Energy (FE) Index was explored as a fracture parameter to characterize and differentiate the cracking resistance potential of hot-mix asphalt (HMA) subjected to the Overlay Tester (OT) test under Monotonic Loading in the laboratory; denoted herein as the OT M test. Mathematically, the FE Index was derived and defined as a parametric ratio of the total FE to the HMA tensile strength and tensile strain at peak failure load per unit crack length under the OT Monotonic Loading testing, with a tensile Loading rate of 3.125 mm/min at a test temperature of 25 °C. Various HMA mixes, commonly used in Texas, with cracking resistance potential ranging from poor to good, were evaluated. Corresponding results indicated that the FE Index has promising potential to be used as a fracture parameter to discriminate and rank the cracking resistance potential of HMAs in the laboratory. While variability was generally within the acceptable tolerance (i.e., coefficient of variation of less than 30%), the FE Index exhibited sensitivity to the mix-design variables and was able to capture the effects of changes in the asphalt-binder content and temperature variations. Thus, this concept should be investigated further with more mixes and validated with field data for subsequent consideration in routine mix-designs and screening for adequate HMA cracking resistance in the laboratory.

Kolluru V. L. Subramaniam - One of the best experts on this subject based on the ideXlab platform.

  • investigation of sub critical fatigue crack growth in frp concrete cohesive interface using digital image analysis
    Composites Part B-engineering, 2013
    Co-Authors: Christian Carloni, Kolluru V. L. Subramaniam
    Abstract:

    Abstract The cohesive stress transfer during the sub-critical crack growth associated with the debonding of FRP from concrete under fatigue Loading is experimentally investigated using the direct shear test set-up. The study focused on high-amplitude/low-cycle fatigue. The fatigue sub-critical crack growth occurs at a load that is smaller than the static bond capacity of the interface, obtained from Monotonic quasi-static Loading, and is also associated with a smaller value of the interfacial fracture energy. The strain distribution during debonding is obtained using digital image correlation. The results indicate that the strain distribution along the FRP during fatigue is similar to the strain distribution during debonding under Monotonic quasi-static Loading. The cohesive crack model and the shape of the strain distribution adopted for quasi-static Monotonic Loading is indirectly proven to be adequate to describe the stress transfer during fatigue Loading. The length of the stress transfer zone during fatigue is observed to be smaller than the cohesive zone of the interfacial crack under quasi-static Monotonic Loading. The strain distribution across the width of the FRP sheet is not altered during and by fatigue Loading. A new formulation to predict the debonding crack growth during fatigue is proposed.

Jin Weon Kim - One of the best experts on this subject based on the ideXlab platform.

  • J-R FRACTURE TOUGHNESS OF NUCLEAR PIPING MATERIALS UNDER EXCESSIVE SEISMIC Loading CONDITION
    2020
    Co-Authors: Jin Weon Kim, Myung Rak Choi, Sang Bong Lee, Yun Jae Kim
    Abstract:

    ABSTRACT This study investigated the Loading rate effect on the fracture resistance under cyclic Loading conditions to clearly understand the fracture behavior of piping materials under excessive seismic conditions. J-R fracture toughness tests were conducted under Monotonic and cyclic Loading conditions at various displacement rates at room temperature (RT) and the operating temperature of nuclear power plants (NPPs), i.e., 316°C. SA508 Gr. 1a low-alloy steel (LAS) and SA312 TP316 stainless steel (SS) piping materials were used for the tests. The fracture resistance under a reversible cyclic load was considerably lower than that under Monotonic load regardless of test temperature, material, and Loading rate. Under both cyclic and Monotonic Loading conditions, the fracture behavior of SA312 TP316 SS was independent of the Loading rate at both RT and 316°C. For SA508 Gr. 1a LAS, the Loading rate effect on the fracture behavior was appreciable at 316°C under both cyclic and Monotonic Loading conditions. However, the Loading rate effect diminished when the cyclic load ratio (R) was -1. Thus, it was recognized that the fracture behavior of piping materials, including seismic Loading characteristics, can be evaluated when tested under a cyclic load of R = -1 at a quasi-static Loading rate

  • simulation of ductile fracture toughness test under Monotonic and reverse cyclic Loading
    International Journal of Mechanical Sciences, 2018
    Co-Authors: Hyun Suk Nam, Yun Jae Kim, Jong Min Lee, Gyo Geun Youn, Jin Weon Kim
    Abstract:

    Abstract This paper presents a ductile crack growth simulation method for Monotonic and reverse cyclic Loading with large-scale yielding using the damage model based on the multi-axial fracture strain energy. The damage model has two parameters which can be determined from tensile and fracture toughness data under the Monotonic Loading condition. The determined damage model then can be used to simulate ductile crack growth subjected to reverse cyclic Loading with large-scale yielding. The proposed method is validated against test data for SA508 Gr.1a and TP316 under Monotonic and reverse cyclic Loading with three different reverse Loading ratios.

  • Effect of Loading Rate on the Fracture Behavior of Nuclear Piping Materials Under Cyclic Loading Conditions
    Elsevier, 2016
    Co-Authors: Jin Weon Kim, Myung Rak Choi, Yun Jae Kim
    Abstract:

    This study investigated the Loading rate effect on the fracture resistance under cyclic Loading conditions to understand clearly the fracture behavior of piping materials under seismic conditions. J–R fracture toughness tests were conducted under Monotonic and cyclic Loading conditions at various displacement rates at room temperature and the operating temperature of nuclear power plants (i.e., 316°C). SA508 Gr.1a low-alloy steel and SA312 TP316 stainless steel piping materials were used for the tests. The fracture resistance under a reversible cyclic load was considerably lower than that under Monotonic load regardless of test temperature, material, and Loading rate. Under both cyclic and Monotonic Loading conditions, the fracture behavior of SA312 TP316 stainless steel was independent of the Loading rate at both room temperature and 316°C. For SA508 Gr.1a low-alloy steel, the Loading rate effect on the fracture behavior was appreciable at 316°C under cyclic and Monotonic Loading conditions. However, the Loading rate effect diminished when the cyclic load ratio of the load (R) was −1. Thus, it was recognized that the fracture behavior of piping materials, including seismic Loading characteristics, can be evaluated when tested under a cyclic load of R = −1 at a quasistatic Loading rate