Fatigue Performance of Geosynthetic-Reinforced Asphalt Concrete Beams
01 Aug 2020-Journal of Materials in Civil Engineering (American Society of Civil Engineers)-Vol. 32, Iss: 8, pp 04020206
TL;DR: In this paper, overlay placement is a quick remedy to rehabilitate cracks observed in asphalt concrete (AC) pavements under repeated vehicular and thermal loadings, which is a common cause of road cracks.
Abstract: One of the common distresses observed in asphalt concrete (AC) pavements under repeated vehicular and thermal loadings is cracking. Overlay placement is a quick remedy to rehabilitate these...
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TL;DR: In this paper, a modified-reinforced composite hot mix asphalt (MRC-HMA) mixture was proposed to examine the fatigue life of this mixture with one of the most traditional methods (i.e., four point bending beam fatigue test) and compare it at constant strain conditions and the strain levels of 500, 700, and 900
Abstract: Fatigue failure is regarded as one of the most common failures in the road pavement and necessitates spending huge cost annually to maintain the road. Asphalt binder modification and asphalt mixture reinforcement are among the commonly used methods to increase the pavement resistance to a failure caused by fatigue. By proposing a modified-reinforced composite hot mix asphalt (MRC-HMA), the present study aimed to examine the fatigue life of this mixture with one of the most traditional methods (i.e., four-point bending beam fatigue test) and compare it at constant strain conditions and the strain levels of 500, 700, and 900 and a temperature of to that of the other three specimens, including control specimens, geogrid-reinforced (GR-HMA) specimens, and nanosilica-modified (NSM-HMA) specimens with 5% nanosilica. In all experiments, the condition to reach the failure stage was assumed equivalent to a 50% reduction in the stiffness coefficient in each load repetition, and the load was applied semisinusoidal at a frequency of 10 Hz without rest. The results showed that the MRC-HMA mixture improved the fatigue life at the strain level of 500 by about 701, 172.5, and 156.4% compared to the control, NSM-HMA, and GR-HMA specimens, respectively. Based on the results, the use of GR-HMA specimens has almost the same results as NSM-HMA ones, but the use of the MRC-HMA mixture can significantly increase the fatigue life of MRC-HMA in all three levels of strain compared to all specimens studied in the present study. Thus, the introduced mixture can be a proper choice for pavements with heavy or light (with a large amount) traffic loads, which usually have a vast adverse effect on the fatigue behaviour of asphalt mixtures.
7 citations
TL;DR: In this paper, the influence of geosynthetic reinforcements on the structural improvement of asphalt overlays placed on distressed pavement layers using repeated load tests was evaluated using a servo-hydraulic actuator.
Abstract: This study aims at evaluating the influence of geosynthetic reinforcements on the structural improvement of asphalt overlays placed on distressed pavement layers using repeated load tests. Full-scale instrumented pavement models were constructed in an indoor steel tank measuring 1000 mm in length, 1000 mm in width and 1000 mm in depth. Full-scale instrumented pavement models consisted of a 650-mm-thick weak subgrade, 250-mm-thick base, 90-mm-thick distressed asphalt layer, binder tack coat, geosynthetic reinforcement (except in control sections), and 50-mm-thick hot mix asphalt overlay. Sensors used in the instrumentation program included earth pressure cells and linear variable displacement transformers installed on the subgrade and surface layers, respectively. Four different geosynthetic types, including woven geo-jute mat (GJ), polypropylene geogrid (PP), polyester geogrid (PET), and fiberglass geogrid composite (FGC) were adopted as asphalt reinforcements. A servo-hydraulic actuator was used to replicate a live traffic wheel load by applying an equivalent single axle contact pressure of 550 kPa at a frequency of 1 Hz. Repeated load tests were terminated after 100,000 load cycles and the behaviour of geosynthetic-reinforced full-scale models was compared with that of unreinforced model. Performance indicators, including Traffic Benefit Ratio (TBR) and Rut Depth Reductions (RDR), were estimated and repeated load test results indicated an increase in the structural performance of geosynthetic-reinforced full-scale models in relation to that of unreinforced model. Among the geosynthetic-reinforced models considered in this study, the FGC-reinforced model showed a comparatively better performance with a maximum TBR of 20 at a permanent deflection of 5 mm and the highest RDR of 56% after 100,000 load cycles, respectively. Maximum reductions of 56% in surface deflection and of 30% in vertical pressure on the subgrade were also observed after 100,000 load cycles in the FGC-reinforced model.
4 citations
TL;DR: In this article , a viscoelastic model-cohesive zone model-random aggregate model (VM-CZM-RAM) composite structure model of AP-GB is proposed to describe the interlaminar complex contact form through the finite-element method.
Abstract: An asphalt pavement with gravel base (AP-GB) is used to alleviate the occurrence of reflective cracks. However, its interlaminar stability is affected by the gravel base’s looseness and interlaminar complex contact form. In this situation, a viscoelastic model-cohesive zone model-random aggregate model (VM-CZM-RAM) composite structure model of AP-GB is proposed to describe the interlaminar complex contact form through the finite-element method. Meanwhile, the influences of gravel embedded in AP-GB interlamination stability are considered. Then based on this model, the effects of vertical load, horizontal shear speed, and interlaminar asphalt spraying dosage on interlaminar stability are investigated systematically. Results show that the interlaminar shear strength is positively correlated with the vertical load and shear speed under the model with the optimal interlaminar gravel embedded rate (5%). The best shear strength is obtained when the interlaminar asphalt spraying dosage is 0.8 L/m2. Finally, a no-demolding specimen and its shear test method were designed to verify the feasibility of the model. The conclusions of this paper can highly help the structural design and application of the AP-GB.
TL;DR: In this paper, the application of paving fabric along with a fresh asphalt overlay has proved its effectiveness in terms of delaying the propagation of reflective cracks, however, this application requires a...
Abstract: The application of paving fabric along with a fresh asphalt overlay has proved its effectiveness in terms of delaying the propagation of reflective cracks. Nevertheless, this application requires a...
TL;DR: In this article, an asphalt pavement with gravel base (AP-GB) is used to alleviate the occurrence of reflective cracks, however, its interlaminar stability is affected by the gravel base's looseness and int...
Abstract: An asphalt pavement with gravel base (AP-GB) is used to alleviate the occurrence of reflective cracks. However, its interlaminar stability is affected by the gravel base’s looseness and int...
References
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TL;DR: In this article, a constitutive model for the asphalt concrete layer interface is proposed, where the tangential and normal stresses at the interface are decoupled and the shear stress and displacement are proportional.
Abstract: A new constitutive model for the asphalt concrete layer interface is proposed. Direct shear tests at four levels of normal load and three temperatures were performed on two types of asphalt concrete layer interface: with and without a tack coat. The shear stress-displacement curves determined in these tests were used to derive the constitutive model, as the tangential and normal stresses at the interface are decoupled. In the proposed model, the shear stress and displacement are proportional until the shear stress equals the shear strength and the interface fails. After failure, a friction model may be used to represent the interface condition. Three parameters were considered to completely describe the interface behavior: the interface reaction modulus K, which is the slope of the shear stress-displacement curve; the shear strength Smax; and the friction coefficient after failure μ. For the interface with a tack coat, K and Smax are not affected by the normal stress level, but they are affected for the i...
141 citations
TL;DR: In this article, a 3D parametric study was conducted to quantify the viscoelastic pavement responses due to different tire configurations: dual and wide-base tires, at three temperatures (5, 25 and 40°C) and two speeds (8 and 72 km/h).
Abstract: A three-dimensional (3D) finite element (FE) parametric study was conducted to quantify the viscoelastic pavement responses due to different tire configurations: dual and wide-base tires, at three temperatures (5, 25 and 40°C) and two speeds (8 and 72 km/h) Three factors affecting pavement responses were investigated: type of moving wheel loading amplitude (continuous, trapezoidal), interface layer condition (simple-friction and elastic-stick models) and lateral surface forces It was found that the continuous loading amplitude, which has an asymmetric stress magnitude and considers the difference between the entrance and exit of the tire, can simulate pavement responses to moving wheel vehicular loading more accurately than the currently used trapezoidal loading amplitude The elastic-stick model resulted in a sensible improvement for predicting pavement responses to dual tire, while the simple-friction model is more comparable to field measurements in the case of the wide-base tire The shear force was
106 citations
TL;DR: In this paper, the influence of geosynthetic reinforcement materials on the flexural behavior of bi-layer bituminous systems was evaluated by means of a four-point bending test under repeated loading cycles and the failure criterion was defined as the number of loading cycles corresponding to the flex point of the permanent deformation evolution.
74 citations
TL;DR: In this paper, an interlaboratory experiment has been organized as part of the RILEM TC 237-SIB/TG4 with a twofold objective: to compare the predictive effectiveness of different experimental approaches and to analyze the behavior of different geogrid types.
Abstract: The use of geogrids at the interface of asphalt layers is currently adopted to improve pavement performance in terms of rutting, fatigue and reflective cracking. Several test methods have been proposed in order to simulate the complex mechanical behavior of reinforced pavements and assist practitioners in the selection of the appropriate reinforcement product. A particular subject of debate is the evaluation of geogrid effects in terms of both flexural strength and interlayer bonding. In this context, an interlaboratory experiment has been organized as part of the RILEM TC 237-SIB/TG4 with a twofold objective: to compare the predictive effectiveness of different experimental approaches and to analyze the behavior of different geogrid types. For this purpose two experimental reinforced test sections have been realized, the first one to prepare samples for the interlaboratory experiment, the second one to analyze the geogrid field performance under heavy traffic conditions. This paper describes the test results obtained by one participating laboratory on double-layered asphalt samples extracted from the first experimental section and compares them with the periodic visual observation of the reflective cracking evolution occurred in the second test section. The laboratory tests were performed following a specific testing protocol that combines interlayer shear tests, repeated loading tests in a four-point bending configuration and quasi-static three-point bending tests, in order to investigate the overall performance of double-layered asphalt systems. Results have shown that geogrid reinforcement does not noticeably influence the flexural stiffness and strength in the pre-cracking phase, whereas the crack propagation speed can be significantly reduced and the failure behavior may change from quasibrittle to ductile, depending on the interlayer shear resistance. Laboratory results were confirmed by periodic visual observation of field performance in terms of reflective cracking evolution.
54 citations
TL;DR: In this article, a comprehensive review of treatment methods available to delay or prevent reflection cracking in rehabilitated pavements and survey current state of practice in addressing this distress is presented, based on the results of literature review and the survey questionnaire, a summarized assessment is presented for each treatment method.
Abstract: The placement of an asphalt overlay on top of an existing pavement is rarely a lasting solution. Due to continuous movement of the existing pavement, existing discontinuities such as cracks and joints propagate through the overlay causing reflection cracking. Reflection cracking is a serious challenge associated with pavement rehabilitation. Practical experience shows that reflection cracking propagates at a rate of 1 in. per year. As the need grows for new rehabilitation methodologies to improve the performance of overlays against reflection cracking, a number of state transportation agencies tasked the authors of this paper to conduct a comprehensive review of treatment methods available to delay or to prevent reflection cracking in rehabilitated pavements and to survey current state of practice in addressing this distress. Based on the results of the literature review and the survey questionnaire, a summarized assessment is presented for each treatment method. Further, a number of treatment methods were identified for further evaluation by the state transportation agencies. For existing HMA pavements, crack sealing and overlay, chip.
50 citations