Reflective cracking reduction by a comparison between modifying asphalt overlay and sand asphalt interlayer: an experimental evaluation

Shafabakhsh, Gholamali; Ahmadi, Saeed

doi:10.1080/10298436.2019.1593410

Cited by 15 publications

(9 citation statements)

References 28 publications

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“…The high content of PMA resulted in better reflection cracking resistance than PMA mixes with normal content [14] • Natural zeolite was added to crumb-rubber-modified (CRM) asphalt binder.…”

Section: Texas Overlay Testmentioning

confidence: 99%

Comparative Analysis of Reinforced Asphalt Concrete Overlays: Effects of Thickness and Temperature

Albayati,

Ajool,

Allawi

2023

Materials

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Reflection cracking in asphalt concrete (AC) overlays is a common form of pavement deterioration that occurs when underlying cracks and joints in the pavement structure propagate through an overlay due to thermal and traffic-induced movement, ultimately degrading the pavement’s lifespan and performance. This study aims to determine how alterations in overlay thickness and temperature conditions, the incorporation of chopped fibers, and the use of geotextiles influence the overlay’s capacity to postpone the occurrence of reflection cracking. To achieve the above objective, a total of 36 prism specimens were prepared and tested using an overlay testing machine (OTM). The variables considered in this study were the thickness of the overlay (40, 50, and 60 mm), temperature (20, 30, and 40 °C), mix type (reference mix and mix modified with 10% chopped fibers by weight of asphalt cement), and the inclusion of geotextile fabric at two positions (one-third of the depth from the base and at the bottom). The research outcomes revealed that a decreased temperature and thicker overlay led to a higher resistance to crack initiation and full propagation, as indicated by the values of critical fracture energy (Gc) and crack progression rate (CPR). Furthermore, the study observed the enhanced crack resistance of overlays in the presence of geotextiles, whether at the bottom or one-third of the depth from the bottom, with superior performance of the former. Despite a slight enhancement in certain properties, the incorporation of chopped fibers in the overlays did not substantially improve the overall performance compared to the reference specimens. Overall, the study provides valuable insights into the variables that influence the ability of AC overlays to mitigate reflection cracking. These findings will aid engineers and designers in making informed decisions regarding overlay design and construction.

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Section: Texas Overlay Testmentioning

confidence: 99%

Comparative Analysis of Reinforced Asphalt Concrete Overlays: Effects of Thickness and Temperature

Albayati,

Ajool,

Allawi

2023

Materials

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“…Thick interlayers, (Figure 3.b) were used for stress-relief and thermal insulation in cold regions in order to reduce shrinkage of the CBC layer [38]. Shafabakhsh and Ahmadi [39] investigated the influence of a modified interlayer and overlay on the propagation of reflective cracks. The interlayer was sand asphalt, and the overlay was an asphalt mixture.…”

Section: Fly Ashmentioning

confidence: 99%

Prevention and remediation measures for reflective cracks in flexible pavements

2022

JCE

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Considering the high price and the number of natural resources used in transport infrastructure, extending pavement lifetime is a priority for engineers. One of the most common issues in flexible pavement maintenance are reflective cracks, which reduce driving comfort and passenger safety. These cracks have two main origins, those initiated by shrinkage of the cement stabilized layer and the cracks reflected from the old pavement to a new overlay. During road maintenance, the usual remediation measure is to overlay and place a new asphalt wearing course over the old, deteriorated pavement surface. After an asphalt overlay is placed on the deteriorated pavement, the overlay can exhibit an identical crack pattern as the layer below. The main cause of reflective cracks is in the cement bound base course (CBC). Due to cement hydration, traffic load, and temperature oscillations, cracks may occur and propagate through upper layers. Much research has been conducted to prevent this problem. Some research, with an emphasis on recycled materials, is presented in this paper. The remediation measures include thin and thick interlayers and modification of the asphalt overlay characteristics.

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“…where N th f demonstrates the number of load cycles to reach the turning point of specimen i and N control f displays the number of loading cycles to reach the turning point of the control specimen. e higher the value of the IF parameter, the greater the ability of the asphalt mixture to delay crack propagation [37]. Besides, having a suitable mechanical interlocking between the asphalt layers minimizes the deformation at the failure point.…”

Section: Improvement Factor (If)mentioning

confidence: 99%

“…Furthermore, modified bitumen decreases stress concentration at the crack tip and increases the number of loading cycles up to failure by deflecting the crack propagation path. e selection of an additive type for bitumen modification is regarded as one of the most important factors in preventing the expansion of cracks to the pavement surface [37].…”

Section: Improvement Factor (If)mentioning

confidence: 99%

Evaluating the Fatigue Resistance of the Innovative Modified‐Reinforced Composite Asphalt Mixture

Shafabakhsh

Akbari

Bahrami

2020

Advances in Civil Engineering

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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 μ ε and a temperature of 20 ± 0.8 ° C 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 μ s 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.

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Reflective cracking reduction by a comparison between modifying asphalt overlay and sand asphalt interlayer: an experimental evaluation

Cited by 15 publications

References 28 publications

Comparative Analysis of Reinforced Asphalt Concrete Overlays: Effects of Thickness and Temperature

Comparative Analysis of Reinforced Asphalt Concrete Overlays: Effects of Thickness and Temperature

Prevention and remediation measures for reflective cracks in flexible pavements

Evaluating the Fatigue Resistance of the Innovative Modified‐Reinforced Composite Asphalt Mixture

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