Browsing by Author "Lastra-Gonzalez, Pedro"

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    Healing by magnetic induction of a novel cold pavement with asphalt emulsion and industrial by-products.
    (2024) De La Fuente-Navarro, Christopher; Lastra-Gonzalez, Pedro; Indacoechea-Vega, Irune; Castro-Fresno, Daniel
    This research evaluated the feasibility of magnetic induction self-healing of a novel cold porous asphalt mixture made from asphalt emulsion and an industrial by-product. The study consisted of three phases: first, the feasibility of magnetic induction healing was determined using a break-heal-break cycle. Secondly, the consequences of the repeated healing process were determined both in the bitumen, through penetration, ring and ball and dynamic shear rheometer tests and in the mixture, through flexural, interconnected voids and permeability tests. Thirdly, the impact of varying the healing cycles on the particle loss performance was evaluated using the cantabro test. The results were as follows: firstly, the use of magnetic induction is feasible and achieves 91% healing in the novel cold porous asphalt mixture. Secondly, regarding the consequences of repeating the healing process: at the rheological level, the viscosity and stiffness of the binder increases while at the mixture level, it is posible to repeat the healing process, since although the healing capacity decreases due to the increased hardness of the binder, the flexural strength also increases with increasing stiffness. Regarding the internal structure and permeability test, repeating the process leads to a reduction in the percentage of interconnected voids, which negatively affects the permeability of the mixture. Thirdly, the healing process by magnetic induction improves the performance against particle loss.
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    Mechanical, rheological and functional consequences of healing of porous asphalt mixtures by magnetic induction
    (2024) DeLaFuente-Navarro, Christopher; Lastra-Gonzalez, Pedro; Indacoechea-Vega, Irune; Castro-Fresno, Daniel
    Magnetic induction technology has been extensively developed so far. However, the mechanical, rheological and functional consequences of repeated self-healing are still unknown. For this reason, this paper investigates the consequences of repeated healing cycles by magnetic induction in four chapters: first, the healing temperature of the experimental mixtures was determined and compared with a reference mixture, that was left to stand at room temperature for 90 days to assess the actual self-healing capacity of the asphalt mixtures. Second, the performance against particle loss was evaluated by applying different healing cycles in the cantabro test and particle loss by brush test. Third, rheological consequences on the binder were determined by penetration, ring and ball and dynamic shear rheometer. Fourth, functional consequences on the mixture were studied in terms of permeability and noise absorption capacity. In this way, we are analyzing the impact of the healing cycles on the mechanical performance of the mixture, the properties of the binder and the functional properties respectively. Regarding the results, healing by magnetic induction in porous asphalt mixtures reduces particle loss to a third. Furthermore, there are no statistically significant differences in the performance of the residual binders of the reference mixture without healing cycles and the residual binder of the experimental mixtures after 20 healing cycles. Finally, with respect to their functional properties, repeating the healing cycles 20 times produces a small decrease in the permeability capacity, which is not statistically significant. At the same time, repeated healing cycles significantly increase the noise absorption capacity of the asphalt mixture, possibly due to a slight draining of the binder, which increases the porosity at the top of the mixtures.
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    Multi-criteria analysis of porous asphalt mixtures with aramid fiber under adverse conditions
    (2024) Delafuente-Navarro, Christopher; Lastra-Gonzalez, Pedro; Slebi-Acevedo, Carlos; Indacoechea-Vega, Irune; Castro-Fresno, Daniel
    This study the functional performance of super porous asphalt mixtures with two types of aramid fibers against adverse events during their service life. This research was organized in 4 phases: first, particle loss after extreme weather conditions was evaluated. Second, the permeability and clogging resistance was assessed. Third, its resistance to fuel spillage was studied. Fourth, a multi-criteria analysis was performed to determine the best performing mixture considering all the studied variables. Regarding the results, mixture with aramid and polyolefin was the best performing blend according to the multi-criteria analysis. The fiber content allowed for acceptable performance in terms of particle loss despite having a higher void content than the reference mixtures. In addition, a higher permeability and clogging resistance was found, so the use of such fibers did not negatively affect the internal structure of the mixture. Finally, it had a higher resistance to fuel spillage due to the use of polymer-modified bitumen.
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    Novel cold asphalt mixture featuring fast curing and self-healing by means of magnetic induction
    (2024) DeLaFuente-Navarro, Christopher; Lastra-Gonzalez, Pedro; Indacoechea-Vega, Irune; Castro-Fresno, Daniel
    Cold asphalt mixtures require a longer curing time and have lower durability than hot asphalt. So, a novel cold magnetic asphalt mixture with industrial by-product and control mixture with virgin steel fibers was designed and compared with a traditional reference mixture curing by oven according to U.S. standard. The research has two main chapters: first, a novel curing process by magnetic induction was evaluated; second, the self-healing capacity of the same magnetic cold mixture by magnetic induction was assessed.
    In the first chapter, fast curing by magnetic induction was compared with the traditional method established by the U.S. Asphalt Institute with respect to evaporated water, time and energy used. Also, the binder was evaluated after the curing process by the penetration test, ring and ball and Dynamic shear rheometer. Finally, the complete mixture was evaluated mechanically by means of the Cantabro test, stiffness modulus and indirect tensile strength. Regarding the results, the novel magnetic induction curing method evaporates the same water percentage using less energy reducing the curing time from days to only hours. In addition, the binder of the experimental mixture with by-products was less affected at the rheological level. Regarding mechanical properties, the experimental mixture shows a statistically equivalent performance than control and reference mixture.
    In the second chapter, the self-healing capacity was determined by means of a rupture-healingrupture test. Then, the healing process was applied in different cycles of the Cantabro test to evaluate its impact on durability against particle loss. Finally, the permeability was measured after 20 cycles of healing. Results show the experimental mixture achieved 83 % self-healing. In addition, applying a heal cycle every 50 revolutions in the Cantabro test allowed tripling the durability against particle loss. Finally, the repetition of healing cycles in the cold mixture affects the internal structure of the mixture, reducing permeability.
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    Rheological and mechanical consequences of reducing the curing time of cold asphalt mixtures by means of magnetic induction
    (2023) DeLaFuente-Navarro, Christopher; Lastra-Gonzalez, Pedro; Calzada-Perez, Miguel Angel; Castro-Fresno, Daniel
    Cold asphalt mixtures are more sustainable because they are manufactured at ambient temperature. However, they are much less applied because they take longer time in the curing process due to the water contained in the asphalt emulsion, which delays the opening of roads. To solve this problem, the option of adding magnetic aggregates to cold asphalt mixtures and heating them by magnetic induction to evaporate the water contained in the asphalt emulsion and reduce curing time has been evaluated. For this objective, different by-products were evaluated as magnetic aggregate and the best one was selected. Four porous asphalt mixtures were then manufactured: an experimental mixture with the selected magnetic particles, a control mixture with virgin steel instead of the by-products, and two oven-cured reference mixtures without magnetic aggregate (one according to the Spanish standard and another according to the U.S. Asphalt Institute guidelines); then, the four mixtures were studied in terms of the curing process, rheological properties of bitumen and mechanical performance of samples. The experimental mixture containing industrial by-products shortened the curing time from 7 and 2 days (Spanish and U.S. Asphalt Institute standard, respectively) to only two hours; rheological and mechanical analysis proved the viability of this technology.
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    Rheological and mechanical evaluation of a novel fast curing cold asphalt concrete made with asphalt emulsion, by-products and magnetic induction
    (2024) DeLaFuente-Navarro, Christopher; Lastra-Gonzalez, Pedro; Indacoechea-Vega, Irune; Castro-Fresno, Daniel
    This work studies the feasibility of a new cold asphalt concrete with 5% voids with fast curing, developed with asphalt emulsion and magnetic induction. Until now, it was impossible to produce fast curing cold asphalt concretes due to the impossibility of compacting and evaporating the water in the asphalt emulsion quickly. Therefore, the aim of this work is to solve the impossibility of compacting the cold asphalt concrete and thus reduce the long curing times. For this purpose, at laboratory level, an experimental cold asphalt concrete was designed with magnetic induction and compared with two reference hot asphalt concretes manufactured according to Spanish standards without magnetic induction (one with 50-70 grade bitumen and another with a PMB45/80-65 type polymer-modified bitumen). The research was carried out in two stages. First, the new cold asphalt concrete was rheologically characterized, the binder recovered from the asphalt concrete was analyzed according to the tests of ring and ball, penetration, dynamic shear rheometer (DSR) and multiple stress creep and recovery (MSCR). Secondly, the new cold concrete asphalt was mechanically characterized, the mechanical performance of the cold asphalt concrete was analyzed by evaluating stability and deformation, dry and wet indirect tensile strengths (ITS), wheel tracking test, stiffness modulus and resistance to raveling dry and wet conditions. Based on the rheological analysis results, the asphalt emulsion recovered from the cold asphalt concrete is extremely soft with a low softening point and a high penetration rate. On the other hand, the values of viscosity, phase angle, stiffness and non-recoverable creep compliance are between those of the bitumen 50/70 and the PMB45/80-65, but closer to bitumen 50/70. As for their mechanical performance, the novel cold asphalt concrete studied presents better resistance to water damage and particle loss, both in dry and wet conditions, but also high permanent deformations and low ITS, probably due to the fact that the residual binder of the emulsion used is softer than the others.