Search

This article presents a new methodology of analysis based on a fast-running experimental procedure to characterise the mechanical response of asphalt mortars in terms of stiffness, ductility, and fatigue resistance. This was achieved using the DMA (Dynamic Mechanical Analyser) threepoint bending configuration. The study was carried out by considering the employment of different types of fillers such cement and CaCO3 and different types of binders such as conventional asphalt binder (B35/50) or modifided polymer-modified bitumen (PMB 25/55–65). From the results of this study, the filler was found to have a greater influence on the stiffness and ductility of the asphalt material, while bitumen had a higher effect on the fatigue life of the asphalt mortar. Fatigue life was observed to increase with the use of a polymer-modified binder, while a lower degree of permanent deformation and higher bearing capacity achieved by the use of cement instead of calcium carbonate as active fillers.

Bituminous mixtures are viscoelastic materials whose mechanical performance is highly influenced by temperature. In addition, during their service life, these types of materials suffer an ageing pr...

Roads play a significant role in the development of societies. Considerable quantities of asphalt mixes are employed in their construction, with hot asphalt mix (HMA) technology being one of the most commonly used worldwide. In recent times, the development of sustainable technologies has become a priority for most governments, and to this end, warm mix asphalt (WMA) can be considered as a cleaner technology that allows for the production of asphalt mixtures under lower manufacturing temperatures. This in turn allows for a reduction in atmospheric emissions and fuel consumption in comparison with HMA. However, due to the novelty of WMA and the length of time required for the analysis of its performance in real roads, information regarding the feasibility of its use is not easy to obtain. This research therefore analyses the potential for manufacturing a WMA using the same discontinuous industrial plant and the spreading and compaction machinery available for a HMA mixture, whilst also including the construction of a trial section that allows for the study of the performance of the WMA during its service life in a real road. The results suggest that WMA can be produced without modifying the industrial manufacturing process, providing asphalt pavements with comparable (or even better) mechanical performance to that recorded when equivalent hot asphalt mixtures are used. These findings are encouraging for the potential use of this cleaner technology in road construction projects.

Climatic actions such as rain, sun or ice are one of the major contributors in asphalt pavement degradation. The effect of these climatic agents can be a long-term process of asphalt mixture deterioration when long rainy or sunny periods are expected as well as a series of freeze–thaw cycles due to wide range of temperature. However, laboratory studies are mainly focused on short-term effect from climatic actions. Thus, the present paper aims to analyze the evolution of the strength and bearing capacity of asphalt mixtures exposed to long-term moisture, several freeze–thaw cycles and diverse days of thermal aging. In addition, the recovery of the material mechanical properties was evaluated when a rest period was applied after climate processes. This study was developed for two different asphalt mixtures (dense and open), finding that air void content has significant influence on the trend of the long-term evolution of mixture properties under moisture action, which is a reversible process unlike the other two climate agents studied. On the other hand, freeze–thaw cycles whose effect is higher on dense mixtures was found to be a short-term process regardless the air void content while thermal aging presented the lowest variations in the properties measured for both types of asphalt mixtures.

Given the high costs associated with using polymer-modified bitumen in asphalt pavement for roads, this research set out to develop more competitive modifiers that are able to offer environ...

The use of modified binders plays a very important role in the construction of more durable pavements. However, the addition of modifiers to the binders could considerably increase their cost, making these materials less competitive. Thus, in recent years, various research studies have been carried out to obtain new modified binders that could lead to an improvement in the mechanical performance of asphalt pavements without a notable increase in their construction costs. To this end, the reuse of wastes and by-products from other industries has been posited as an interesting and sustainable alternative. This study investigates the reuse of scraps from reclaimed geomembranes composed of low-density polyethylene and polyester fibers as modifiers for asphalt binders. For this purpose, different blends of this waste and neat bitumen were manufactured and tested [penetration, softening point, storage stability, frequency sweep, multiple stress creep-recovery (MSCR), and time sweep tests). In addition, ...

Bituminous mixtures are visco-elastic materials whose mechanical performance is highly influenced by temperature. In addition, during their service life, these type of materials suffer an ageing process which induce an increase in bitumen viscosity and therefore, a variation in the response of the mixture. The changes produced by these phenomena are mainly manifested in terms of stiffness, which could exert a considerable influence on the fatigue cracking resistance of asphalt materials. In this respect, this paper attempts to provide a better understanding of the effects caused by temperature and ageing on the resistance of bituminous mixtures to the propagation of cracking phenomena. For this purpose, the rheological response of the binder has been correlated with the mechanical performance offered by the bituminous mixture.

Crumb rubber modified binders are environmental-friendly alternatives to polymer modified bitumens in asphalt mixtures. This paper compares the performance of both types of binders with different modifier contents. Six binders were characterised by conventional tests and analysed using the UCL method. This method evaluates different properties of binders regarding their role in asphalt mixtures (cohesion, water and thermal sensitivity and resistance to ageing). Results showed that i) crumb rubber concentration has to be higher than that of SBS-polymers in order to obtain a similar performance to that of SBS-polymer modified bitumen; ii) crumb rubber modified binders are more stable than SBS-polymer modified binders in terms of modifier concentration; iii) crumb rubber modified binders exhibited less water sensitivity and similar thermal and ageing susceptibility to SBS-polymer modified binders; iv) linear relationships have been found between modifier concentration and the properties studied for both kind of binders., Los betunes modificados con polvo de neumático (PN) son alternativas ambientalmente sostenibles a los betunes modificados con polímeros. Este artículo compara el comportamiento de ambos tipos de betunes con varios contenidos de modificador. Para ello, se caracterizaron seis betunes mediante ensayos convencionales y método UCL. Este método evalúa propiedades de ligantes para su uso en mezclas bituminosas (cohesión, sensibilidad al agua, térmica y al envejecimiento). Los resultados muestran que i) la concentración de PN ha de ser más elevada que la de polímeros para obtener comportamiento semejante; ii) los betunes con PN son más estables ante cambios en la concentración de modificador que los betunes con polímeros; iii) los betunes con PN presentan menor sensibilidad al agua y equivalente susceptibilidad térmica y al envejecimiento que los betunes con polímeros; iv) se encontraron buenos ajustes lineales entre la concentración de modificadores y la evolución de las propiedades estudiadas.