Reflective Cracking Included into Routine Design of New Asphaltic Pavements (original) (raw)
Related papers
Load demands on pavements, due to repeated vehicle loads and environmental conditions, generate a constant deterioration of the structure, which causes the loss of mechanical properties, thereby producing a structural and functional loss on the road. Nowadays, one of the most common problem, which is difficult to control due to these load demands, is reflective cracking, a phenomenon that explains the propagation of existing cracks in lower layers or coinciding with joint movements of an aged pavement, towards the new reinforcement layer, which copies the pathology of the same. The study evaluates the behavior of reflective cracking while varying the location of the geosynthetic material between each asphalt mix layer, and subjecting the system to dynamic loading. The geosynthetic reinforcement considerably delays the progression of the crack, and the greatest effectiveness is obtained when this material is located nearest to the most stressed fiber of the reinforcement layer.
The traffic and temperature effect on the reflective cracking
2008
This paper presents a study on the influence of the effects of temperature variations, in comparison to the traffic effects, on the reflective cracking behavior. It intends to contribute to the improvement of the pavement overlay design methods which consider reflective cracking as one among distress criteria. The development of this study was based on the numerical simulation of the overlay behavior, through the implementation of numerical thermal and mechanical models based on the finite element, considering the simultaneous action of traffic and temperature variations and their influence on reflective cracking. For overlay design purposes, it is important to consider temperature variations in the evaluation of the overlay behavior produced by the reflective cracking. The expected performance of an asphalt rubber hot mix, produced by the wet process with 20% crumb rubber was compared to a conventional asphalt taking into account the performance of these mixes.
Evaluating Alternative Solutions to Reflective Cracking Through Asphalt Overlays
Transportation Research Record, 1989
The problem of reflection cracking through asphalt overlays can be approached from the design perspective of the factors or mechanisms involved, the alternative treatments available, and the analyses and testing required to evaluate the treatments. Then, a selection of the best alternative, provided it satisfies economic criteria, can be made and implemented. This paper concentrates on evaluation and first illustrates how an analytical method, based on a wide-crack band theory in finite element formulation, can effectively be used for the first step of the process. Then, it illustrates how the most promising alternative treatments can be experimentally evaluated. Test procedures and example results are used for this purpose, and relationships between induced stress, or strain energy, and cycles to failure are presented. Selection, installation, and follow-up considerations are briefly discussed. It is pointed out that even with the most technically and economically feasible alternat...
International Journal of Pavement Engineering, 2019
Reflective cracking is a frequent type of distress in asphalt concrete (AC) pavements that decreases pavement service life in a newly constructed AC overlay. In this study, natural zeolite and hydrated lime were added to crumb rubber modified (CRM) asphalt binder in order to assess their effects on reducing propagation of reflective cracks in composite pavements. CRM asphalt binder containing these additives was used in both AC overlay and sand asphalt interlayer to investigate crack propagation in the composite specimen under dynamic cyclic loading. The results show that asphalt interlayer modification is more effective than AC overlay modification (using CRM binders containing additives) in controlling reflective cracks. In other words, sand asphalt interlayer modification is more capable of absorbing the energy of crack propagation and, consequently, delaying the crack propagation. The results also indicated that simultaneous modification of both the interlayer and overlay significantly decreases reflective cracking potential. With respect to the significant role of additive type in crack propagation delaying, the results show that CRM binders containing natural zeolite are more efficient in crack mitigation compared to CRM binders containing hydrated lime.
Development of High Performance Asphalt for Prevention of Reflective Cracking
2010
Many methods for prevention of reflective cracking by use of sheets, grids or stress absorbing membranes have been applied for the existing concrete slab pavements or asphalt pavements with severe cracks. Stone Mastic Asphalt (SMA) with high performance asphalt is developed for prevention of reflective cracking. The asphalt is 177 in penetration and 84 degree Celsius in softening point (TR&B). It is modified asphalt with a high-content SBS and a small amount of newly developed additive. The m-value by BBR test of the asphalt is twice that of conventional SBS-modified asphalt. The SMA with the developed asphalt is high in stress absorbing capacity and flexibility as well as in rutting resistance. The number of load cycles to rupture by flexural fatigue test of the SMA with this asphalt is over 200 times as great as that of the SMA with a conventional modified asphalt. Two test pavement sections were built in August 2003 on a national highway in Niigata Prefecture. The objective of the test was to observe asphalt overlays on concrete slab pavements. The thickness of concrete pavement was designed for 1,000 heavy vehicles per day. One of the test sections consisted of a 6-cm thick SMA and the other consisted of a 3-cm thick dense graded asphalt concrete plus a 3-cm thick stress absorbing membrane interlayer (SAMI) on the concrete slab. Four years after overlaying, an inspection of reflective cracking was performed. The percentage of reflective cracking was 0.1% in the SMA section and 10.2% in the SAMI section From these observations, it could be concluded that the SMA with the developed high performance Asphalt might be useful for overlays to prevent reflective cracking on concrete pavements.
Mitigation of Reflection Cracking in Asphalt Concrete Overlay on Rigid Pavements
E3S Web of Conferences
Reflective cracking is one of the primary forms of deterioration in pavements. It is widespread when Asphalt concrete (AC) overlays are built over a rigid pavement with discontinuities on its surface. Thus, this research work aims to reduce reflection cracks in asphalt concrete overlay on the rigid pavement. Asphalt Concrete (AC) slab specimens were prepared in three thicknesses (4, 5, and 6 cm). All these specimens were by testing machine designed and manufactured at the Engineering Consulting Office of the University of Baghdad to examine for the number of cycles and loads needed to propagate the reflection cracking in the asphalt concert mixture at three temperatures (20, 30, and 30°C). It was noticed that the higher thickness AC mixtures increased the reflection cracking performance life of the AC overlay. Also, it was found that the number of crack initiation and failure cycles increased as the temperature increased. In contrast, the increased temperature decreased the required...
Reflective Cracking in Asphalt Overlays Reinforced with Geotextiles
RILEM Bookseries, 2016
In this paper, the effect of asphalt overlays, which were reinforced with geogrid, modified by sasobit and combination of them on the rehabilitation of reflective cracking, is studied. The laboratory tests were conducted under dynamic loading in bending mode to investigate reflective cracking retardation compared to reference samples. The results illustrated that in a certain range of variables, temperature variations, and sasobit percentages are the most effective parameters on fatigue life and other responses. Another effective variable was the type of interlayer in asphalt slabs. Furthermore, it has been found that the combination of samples (modified by sasobit, reinforced with geogrid and a 3cm sand asphalt layer) (1SP.G.SA & 2SP.G.SA) had a better performance such as improving fatigue life and reducing crack propagation in all loading and temperature conditions compared to the reference samples. Based on the image processing results, the process and shape of crack growth vary greatly at different temperatures. Generally, at low temperatures (20 °C) and frequencies, the cracks grow from bottom to top, and the width of them gets smaller. However, with increasing the temperature and loading frequency, the top-down cracks are also observed, which is due to the reduced resistance of the asphalt resulting from the reduction of adhesion and the fastening between the aggregate and bitumen.
A Comprehensive Review on Reflective Cracking: Concept, Mechanism, and Laboratory Performance Tests
Asphalt overlay is one the common rehabilitation alternative to mitigate a deteriorated flexible or rigid pavement. In such case, the cracks from existing pavement rapidly propagate through the asphalt concrete overlay, which makes this solution as a less durable alternative for rehabilitation purpose. The appearance of existing cracks or joint from underlying pavement through the surface of new overlayed bituminous surface is commonly referred as reflective cracking. This cracking usually appears in the early age of overlay serviceability. There are two main roots of reflecting presences cracks though new surface: traffic and environmental loading. Many studies have been done to understand the mechanism of each loading and its contribution to the reflective cracking initiating and propagation process. There is not a complete solution for preventing of such cracks in AC overlay yet, while many types of research concentrated on the retardation of reflective cracking in the AC overlay. In this review, the significant factors involved in initiating and propagation process of reflective cracking were reviewed and discussed, and then the mechanism of two primary external loading was explained. The finding showed that incorporation of an interlayer effectivity enhances the reflective cracking resistance. And also, modification of used asphalt mixture, overlay thickness, using stress relieving interlayer and incorporation of stress absorbing interlayer have an effective influence on retardation of reflective cracking in AC overlay.