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Volume 23, No. 42Journal 42, July 2021 - January 2022

DOI:https://doi.org/10.15517/2m3th276

Published November 19, 2025

Scientific Papers

  1. Rafael Ernesto Villegas Villegas, María Fernanda Abarca Jiménez (Author)

    Equipment to determine storage times of modified asphalts at critical conditions

    This paper attempts to design a storage tank sized for laboratory use, aiming to study the stability of modified asphalt during storage. The tank design seeks to maintain similar dimensions to those of industrial tanks for asphalt storage. Also, it aims to promote phase separation to analyze the storage under critical conditions. For this reason, this research carries out a comparison of commercially available tanks and their dimensional ratios, as well as studying the theories of sedimentation and phase separation. The main objective of this document is to provide a mechanical design of a storage tank that can be manufactured with accessible materials, which allow to perform the necessary sampling to examine the stability of modified asphalt under critical conditions of storage. In addition, the document establishes bases for the approach of a model that contributes to the determination of maximum storage time. It pretends to verify the quality of the modified asphalt design.

  2. Nicole Cajina Cruz, Alejandra Baldi, Edgar Camacho Garita, José Pablo Aguiar Moya (Author)

    Performance evaluation of modified asphalt mix with blister PVC waste

    The modification of asphalt mix with waste polymers provides several benefits. Among the most important is the optimization of the performance of the mix and the increase in its useful life. Not to mention a reduction in the amount of plastic waste that does not have an adequate waste management.

    This article shows the results obtained from a study where a blister type waste material (composed of polymers such as PVC) was incorporated into an asphalt mixture by the dry method. Method in which, prior to the asphalt adhesion, the modifier is incorporated to the mix in substitution of part of the fine aggregate. The purpose of the study was to evaluate the performance of the mix and compare its mechanical behavior with a conventional mix.

    For the project development, the modifier was characterized, and the appropriate percentage was selected so that the design of the modified mixture would comply with Superpave requirements. With the optimized design, the test specimens were prepared, and their performance was evaluated based on the following tests: four-point beam bending, Hamburg wheel, retained tensile strength (moisture damage) and dynamic modulus. Since an adequate behavior of the modified mix was observed, its sensitivity was evaluated in a pavement structure; identifying in which layers of the asphalt mix should the material be used.

  3. Jaime Allen, Andrea Zúñiga López (Author)

    Measurement of quality-of-life perception regarding satisfaction with public transport in Costa Rica

    The issue of mobility is increasingly important in Costa Rica; therefore, it becomes relevant to improve the public transport system in the country. To determine which elements of the public transport system in Costa Rica affect the quality of life according to the users′ perception, it is essential to know their opinion regarding the conditions in which the service is provided. To identify the components of the structure of the public transport system in Costa Rica that have a greater impact on the quality of life of its users, the results of a survey on the effect of the use of public transport on quality of life were analysed. The data were collected by means of a questionnaire applied to workers and students at the University of Costa Rica (UCR). Structural Equation Models (SEM) were used as an analysis tool, which are a multivariate statistical tool that allows studying the relationship between latent and observed variables. The SEM allowed verifying that satisfaction with the use of public transport is a domain that affects satisfaction with the quality of life, in other words, for Costa Ricans, the perception of being satisfied with their quality of life is influenced by the perception of satisfaction they have with the use of public transport.

  4. Daybis Tencio González, Alejandra Baldi, José Pablo Aguiar Moya, Bárbara Miranda Morales (Author)

    Mejoras al ensayo de resistencia del enlace adhesivo de ligante asfáltico en materiales para pavimentos

    The study of mechanical properties of pavement materials is an essential part for their initial characterization. Therefore, the reproducibility and constant improvement of the tests involved allow to obtain faithful results, reducing the potential errors and variability that might occur during sample preparation. For this reason, this study focuses in establishing criteria and nominal values to obtain an adequate finish in the aggregate sources. This intends to reduce the standard deviation of the uniaxial tensile test, carried out by means of the bitumen bond strength test on dry conditions. The aggregates were treated by a sanding process for 60 seconds, repeating such cycles 10 times per sample. Also, abrasive bands of varying grain numbers were used. A Pull-Off Tensile Strength (POTS) of 2.39 (0.29) MPa was achieved, where the value in parentheses corresponds to the standard deviation. This value was selected due to the best conditions found in the experiment. Furthermore, a linear model obtained by a factorial design demonstrated the main effects provide up to 84 % correlation with the pneumatic stress and up to 78 % with its standard deviation, which is considered satisfactorily since the p-value defined in this research as the approval probability for the recommended conditions is 6,56·10-4, demonstrating statistical significance.

  5. Angie Jiménez (Author)

    Mechanical performance analysis of an asphalt mixture modified with bamboo fiber

    International organizations such as the UN recognize the importance of acting against climate change. For this reason, several countries such as Costa Rica, plan to achieve carbon neutrality in the coming years. As a result, the use of biodegradable materials in different applications has increased. In this regard, this article presents a sustainable alternative to asphalt mixture additives: the use of bamboo fibres. Therefore, one of the objectives of this research is to promote the use of bamboo, which holds multiple benefits to the environment such as: carbon fixation, avoids soil erosion, generates job opportunities related to cultivation, among others. It is worth mentioning that the culm fibres are used in this research as a final product and not as a waste, this way the plant grows again after harvesting, generating a sustainable cycle.

    This research presents the analysis and mechanical performance of an asphalt mixture modified with bamboo fibres of the guadua angustifolia species. The main objective was to evaluate its mechanical behavior of the resulting mixture by means of the SUPERPAVE methodology. As a result, an improvement in the resistance of the mixture to fatigue and moisture damage was obtained, which is promising and opens a possibility to the use of fibres in these materials.

  6. María Paula Montes de Oca Hidalgo, Wendy Sequeira Rojas, Tania Ávila Esquivel, José Pablo Aguiar Moya (Author)

    Performance evaluation of rigid pavements in Costa Rica

    The need to understand the typical deterioration of rigid pavements in Costa Rica is recognized, since there are no design techniques or information at a constructive level that considers the country's climatological and traffic variables. To complement the existing information, an evaluation is proposed to determine the typical deterioration of rigid pavements in Costa Rica.

    The evaluation of rigid pavements was based on a visual auscultation and an automatic survey using Geo 3D. Initially, the deterioration of each of the seven projects was surveyed and used to calculate their PCI (Pavement Condition Index) and to determine the typical deterioration. Then, the climatological and traffic characteristics of each project were identified and related to the deteriorations. Finally, the relationships obtained were used to create the initial deterioration prediction models.

    It was observed that the typical deteriorations in Costa Rica are joint seal damage (21,22 %), aggregate spalling (13,58 %), aggregate polishing (13,10 %) and linear cracking (7,08 %). In addition, the deteriorations are related to precipitation, temperature, and equivalent axis. Therefore, it is recommended that the results of this research serve as a basis for future deterioration prediction models.

  7. Michelle Münkel Jiménez, Alejandra Baldi, José Pablo Aguiar Moya, Rafael Ernesto Villegas Villegas, Natalia Hernández Montero (Author)

    Effect of polymers and waste cooking oil on asphalt performance range

    Permanent deformation and fatigue are the main problems on Costa Rica's highways, and these are directly related to the asphalt binder. This study seeks to define dosage ranges for polymers and Waste Cooking Oil (WCO) to improve the performance of modified asphalt by improving resistance to fatigue and permanent deformation. The used materials were then characterized. Tests were carried out to determine how the binder would interact with the WCO. Then, the different dosage combinations of both WCO and commercial polymer, SBS or RET in each sample of modified asphalt were selected based on the experimental design. Finally, the sample performance grades (PG) were measured, and their resistance to deformation was evaluated by advanced rheology testing. Waste cooking oil was found to lower the upper and lower limit of the PG. It was also evidenced that the presence of the WCO affects the interaction of the asphalt with the SBS. However, the upper limit of PG increased 2 degrees without affecting the intermediate and low temperatures for the samples modified with RET and oil. Based on the statistical analysis it was determined that the polymer used in each sample (SBS or RET) was the factor that generated the most significant differences in resistance to permanent deformation and fatigue. The elastic recovery was mostly influenced by the polymer dosage. It was also determined that the difference in the amount of WCO used in the samples of the experimental design did not generate significant changes in the measured variables. Finally, the polymer and WCO dosage ranges needed to reach the PGs required in Costa Rica were determined. Generally, the asphalt design guidelines used in the country are established to meet different requirements to those present in Costa Rica. Therefore, this study allows to lay the foundations of a guideline for the asphalt modification process and provides more detail on how to guarantee a good performance of national asphalt.

Literature Review

  1. Olver Alexander Tábora Cruz (Author)

    Effect of distractions due to the use of the cell phone while driving

    Distracted driving is one of the most important human factors in transportation safety and it is, therefore, a risk that is becoming a growing concern for road safety. Research establishes that cell phone use may be the most important source of distraction for drivers inside the vehicle since its use adds cognitive, physical, or visual demands on the driver towards a secondary task that diverts attention from critical activities for a safe driving, and then, can adversely affect driver behavior and performance. The objective of this research was to study the effects of distractions due to cell phone use on the driver's responses during the driving task and its link with the occurrence of traffic accidents. The results suggest that cell phone use, regardless of the tasks and modality used, has a negative effect on the behavior and performance of drivers and, therefore, users who use cell phones while driving are at greater risk of being involved. in a traffic accident, mainly older and younger drivers, the latter being those who are subject to greater exposure and high risks in the face of this distraction.

Ackowledgements