KIcandKIIcmeasurement for hot mix asphalt mixtures at low temperature: Experimental and theoretical study using the semicircular bend specimen with different thicknesses

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The effect of some important testing conditions including test specimen (SCB and ENDB), fracture mode (I and II), loading rate (0.5, 1.0, and 5.0 mm/min), and temperature (−5°C, −15°C, and −25°C) is evaluated on fracture toughness of asphalt material containing different percentages of fibers (0%, 0.025%, 0.05%, and 0.1% of unit weight). The experimental and numerical results show that the addition of 0.025%, 0.05%, and 0.1% of the polyolefin–aramid fiber in asphalt mixture increases the fracture toughness of the control mixture by about 8%, 17%, and 23% in pure mode I and 7%, 16%, and 24% in pure mode II, respectively; which are among the most promising enhancements compared to other fibers. Results also reveal that fracture toughness at mode I obtained from the SCB and ENDB specimens is similar. However, the mode II fracture toughness obtained from the ENDB specimen is about 12% higher than the corresponding value obtained from the SCB specimen.

Section: Introductionmentioning

confidence: 99%

Crack resistance of fiber‐reinforced asphalt mixtures: Effect of test specimen and test condition

Hajiloo

Karimi

Aliha

et al. 2022

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“…Review of literature reveals that there are many limited test results for K IIc value of asphalt mixtures and almost all of them have been obtained by testing fixed test geometry (i.e., asymmetric SCB specimen). [53][54][55][56][57][58] On the other hand and according to the literature, despite K Ic value, mode II fracture toughness of brittle materials may depend significantly on the geometry and loading type of the test sample. For example, Aliha and Ayatollahi 59 and Aliha et al 60 showed that mode II fracture toughness of brittle polymeric material (Plexiglas) may vary significantly (from 0.5 K Ic to 1.4 K Ic ) when the test specimen used for K IIc testing is varied.…”

Section: Introductionmentioning

confidence: 99%

Influence of testing method on mode II fracture toughness (K_IIc) of hot mix asphalt mixtures

Liu

et al. 2022

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Till now, only very limited test results have been reported for mode II fracture toughness (KIIc) of asphalt mixtures. In the absence of any standard testing method for determining KIIc value for these materials, in this research, an experimental program is done to measure and investigate this parameter at low‐temperature using four different test specimens and configurations. The specimens have circular and semi‐circular shapes but with different crack types and loading setup namely: center cracked circular disc (CCCD), inclined cracked semi‐circular bend (ISCB), asymmetric semi‐circular bend (ASCB), and asymmetric edge notch disc bend (AENDB). The test results showed that KIIc depends significantly on the geometry and configuration of test sample such that its value determined from the AENDB sample is about twice the KIIc value of ISCB specimen. Among the investigated samples, the AENDB results can simulate more realistically the actual and field conditions of real cracked overlays subjected to traffic loading. KIIc results are also predicted successfully using two fracture criteria capable of considering the influence of geometry on mode II cracking.

“…In recent years, several researchers have used different laboratory tests including the semicircular bending (SCB) test, 20–28 the dissipated creep strain energy (DCSE) test, 29 the disc‐shaped compact tension (DCT) test, 30,31 the edge notch disc bend (ENDB) test, 32–39 and so on 40,41 for investigating and analyzing the fracture behavior of asphalt mixtures. However, many of these laboratory tests cannot simulate exactly the cracking mechanism of real asphalt mixture in the field 23,36,42–53 . On the other hand, employment of laboratory samples in the real scale of pavement layers and subjected to actual traffic loading is impossible or at least is a very expensive and time‐consuming process.…”

Section: Introductionmentioning

confidence: 99%

“…However, many of these laboratory tests cannot simulate exactly the cracking mechanism of real asphalt mixture in the field. 23,36,[42][43][44][45][46][47][48][49][50][51][52][53] On the other hand, employment of laboratory samples in the real scale of pavement layers and subjected to actual traffic loading is impossible or at least is a very expensive and time-consuming process. Therefore, utilizing numerical analyses can be used as a suitable method to study the fracture behavior of the cracked asphalt pavement.…”

Section: Introductionmentioning

confidence: 99%

Mixed mode I+II fracture parameters and cracking trajectory of heterogeneous multilayer pavement structure containing reflective crack

Ziari

Aliha

Fard

et al. 2022

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Using aggregate generation and packing algorithm technique coupled with finite element method, a part of reconstructed asphalt pavement structure with five layers and containing a bottom-up crack was simulated. For more realistic modeling and more accurate analyzing the cracking behavior of pavement, a region surrounding the initial crack (and bottom-up crack) region and its neighborhood was modeled as a heterogeneous two-phase (aggregate/mastic) mixture. The results of numerical analyses showed that a significant difference exists between the crack tip fracture parameters (i.e., K I , K II , K eff , T-stress, and Biaxiality ratio) of the homogenous and heterogeneous models. The heterogeneous simulation (in this case study) leads to approximately 70% reduction in the effective stress intensity factor. Furthermore, it was shown that the fracture trajectory of a simulative reflective cracking (SRC) test conducted on a real bilayer asphalt beam sample can be predicted well by modeling the beam layers as a heterogeneous two-phase mixture. K E Y W O R D Saggregate generation and packing algorithms, bottom-up crack, finite element method, fracture parameters, reflective cracking trajectory, two-phase heterogeneous asphalt modeling