Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

The options for National Development are directly linked to proper management of Road Infrastructure; this requires investment, planning, discipline, and periodic evaluations.

Road maintenance holds a very important place in the work of those responsible for the country's road infrastructure.

The new structural pavement design method based on mechanistic-empirical principles was recently developed in the United States through NCHRP Project 1-37A (Development of Mechanistic-Empirical Pavement Design). This method requires new types of testing for mixture characterization, such as dynamic modulus testing and indirect tensile strength, as well as detailed traffic and climate data. Due to the novelty of the method, the need for new testing equipment, and the users’ lack of familiarity with the procedure, the method has not yet been officially adopted. To date, very few pavements have been designed using this new approach. This study documents one of the first efforts to incorporate the required testing protocols for structural pavement design using the new mechanistic-empirical program. The dynamic modulus of two 19-millimeter asphalt mixtures was determined using the tests proposed in NCHRP Report 465: Simple Performance Tests for Asphalt Mixtures (SPT). One of the mixtures was prepared with unmodified PG 64-28 asphalt, while the other was made with PG 58-34 asphalt modified with 25% TLA (Trinidad Lake Asphalt). Using the results from the SPT and the Superpave volumetric properties, the mechanistic-empirical pavement design method was applied to predict pavement performance under typical Utah conditions over a 20-year period. Based on the results of this study, the economic benefits of asphalt modification were evaluated in terms of pavement lifespan under given traffic and climate scenarios. This lifespan was based on specific types of pavement distress, such as permanent deformation (rutting), thermal cracking, and others. With these new methods, highway agencies can more easily determine whether the additional cost of asphalt modification is justified based on the expected performance of the pavement. The adoption of the new mechanistic-empirical design system is recommended.

This article describes the execution of both destructive and non-destructive dynamic laboratory tests on a porous asphalt material modified with recycled polyethylene strips derived from milk bags, with the objective of determining its properties and optimal temperature range for use. The plastic material was introduced into the asphalt mixture during the blending of the aggregate and asphalt, in strips approximately 40 mm x 50 mm in size. Dynamic modulus tests were carried out at 10, 20, and 30°C, and at frequencies of 1.6, 2.5, and 5.0 Hz. Fatigue laws were evaluated at three different strain levels and at temperatures of 15, 25, and 35°C. Rutting tests were performed using the LCPC (Laboratoire Central des Ponts et Chaussées, France) methodology at 60°C and 42 rpm. The main results obtained included the optimal temperature ranges for using the material, as well as the improvement percentages in its rheological and drainage properties.

The delivery time of a civil construction project is one of the most critical factors requiring thorough planning and control in order to achieve efficiency and effectiveness for the project owner. Every owner seeks to obtain the completed civil works as soon as possible—whether to sell, lease, or use the facility—thus allowing for an earlier return on investment or the fulfillment of commercial objectives. In the case of public works, the end user—the citizen who relies on roads, schools, or public hospitals—expects access to these services as soon as possible in order to meet their needs. In this way, the benefit of the public work is delivered to the region within the required timeframe, avoiding delays that could disrupt the provision of public services. In the field of transportation, roads completed within a reasonable period enable regional connectivity and facilitate the economic development of an area by improving the mobility of people, vehicles, and goods. On the other hand, when road construction projects experience significant delays, regional and national economic development is likewise hindered. (ref. No. 2 and No. 6)

Various types of equipment have been implemented worldwide to measure the coefficient of friction on aircraft taxiways. In our case, special emphasis is placed on the use of the GripTester, a British-made device whose configuration allows for continuous data collection. It operates using a braked test tire with a slip ratio of 15%. Additionally, a constant flow of water is maintained to simulate a critical scenario for aircraft operations—namely, the presence of water on the runway.

The study evaluates the mechanical behavior of dense asphalt mixtures through laboratory permanent deformation tests conducted at 60 °C and a frequency of 1 Hz, using slabs compacted with a pneumatic compaction table. To compare the asphalt mixtures, aggregates sourced from the Amazon region (State of Pará) were used, along with petroleum asphalt cement (CAP 50/60) supplied by the Lubricants and Petroleum Derivatives Refinery of the Northeast (LUBNOR). The mixtures compared featured gradations within the limits of Band C defined by the National Department of Transport Infrastructure (DNIT), and gradation curves developed using the Fuller or Talbot equation, referred to as the practical curve (PC) and theoretical curve (TC), respectively. The findings indicate more satisfactory results for the theoretical curves when compared to the practical curve commonly used in the Amazon region.

With the emergence of new, more sophisticated mechanistic-empirical pavement design guides at the international level, we are compelled to study them and, where feasible, consider their implementation. However, are these guides truly applicable to Costa Rica? Were they conceived and developed for environmental conditions, loading scenarios, soil types, and materials similar to those found in our country? Clearly, the answer is NO.

The traffic safety requirements currently demanded of road surfaces have led to the development of materials with different characteristics than those traditionally known. The Drainage Asphalt Mix (DAM), also known as Porous Asphalt Mix (PAM), is a material that meets these requirements.