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Volume 13, No. 24Journal 24

DOI:https://doi.org/10.15517/ty0zat56

Published October 28, 2025

Scientific Papers

  1. Proposed methodology for the design of flexible pavements using geosynthetics as reinforcement

    This work presents a design proposal for the design of flexible pavements using geosynthetics to reinforce the granular base materials and protect the subgrade. The proposal was developed by a theoretical-conceptual research work of the use of geosynthetics in pavements. The basis benefits of placing geosynthetics in the subgrade-granular base interface, as a function of the non-linearity response of the materials, is discussed. Considering, the complexity of the problem, the analysis presents logical results that can support to establish the principles for a rational design procedure. The analysis was conducted with the AASHTO-93 Design Procedure, and its concepts.

  2. Use of ultrasound for the evaluation of density homogeneity in trapezoidal asphalt concrete test specimens

    In the French methodology, two of the most important tests for the elaboration of asphalt concrete mixtures are: the fatigue test and the complex modulus test. These tests are made with trapezoidal samples extracted from pre-compacted blocks, either extracted from the field or prepared at the laboratory, which must have uniform granular distribution and void homogeneity. Generally, the method used to evaluate the homogeneity of the block is the gamma densitometer; however, this equipment is not available. For this reason, with the ultrasound technique, we look for a way to evaluate the homogeneity of the blocks while addressing the precision and statistic limitations showed in the test procedures for fatigue and modulus. This work evaluates the use of the ultrasound method by the direct transmission mode, on asphalt concrete blocks to determine the wave's propagation speed. One of the choosing criteria for the trapezoidal samples which will be used for the fatigue and complex modulus tests is the void percentage. The resulting values of the void percentages for the trapezoidal samples were compared with the wave speeds obtained by the ultrasound test. With the purpose of facilitate the data analysis, the results are presented in a graphic form.
    This study verified that, even though the ultrasound test can detect the homogeneity variation in the asphalt concrete blocks, the precision level of the equipment being used, doesn't allow yet the use of this test with the objective of selecting the blocks to perform the fatigue and complex modulus tests, because the selection of the final test samples is very rigorous.

  3. Hydraulic behavior, benefits and limitations of applying a SDGA to a flexible pavement structure

    The principal design criteria for flexible pavement structures have been based on the density and stability. In last years it has been detected that the behavior of these structures as drainage systems are not convenient, allowing important water infiltrations which affects its durability. Installation of an Open-Graded Drainage System (OGDS) in flexible pavement structures is thus convenient in order to reduce the harmful effects that can produce the infiltrated water. The present study is based on an experimental analysis in order to evaluate the hydraulic behavior, the benefits and limitations of the application of an OGDS in flexible pavement structures for extended operation periods in Bogota.
    To achieve this objective two experimental models were constructed, one representing a conventional flexible pavement structure and another representing a flexible pavement with a OGDS. The preliminary tests consisted of pouring water with methylene blue on each one of the constructed structures, allowing the visualization of its path across the layers. With this experiment it was concluded: ) asphalt surface presented a secondary permeability and the water infiltration is developed in few minutes; (li) on conventional flexible pavement structure model the water infiltrated was caught in the interface between the pavement surface and the granular base; (ili) on the model which includes an OGDS, the infiltrated water was evacuated immediately without accumulation zones. Due to the presence of solids in runoff water, it was conceived an experimental method in order to estimate the operation periods of this drainage system, based on the study of the runoff water characteristics for Bogota and the clogging of this system. With this study, the useful life of an OGDS was assessed as 5.43 years without taking into account the maintenance nor real hydrological behavior dry weather/storm weather periods. The results show the inclusion of an OGDS in flexible pavement structures could be an interesting method for the drainage of infiltrated water.

  4. Linear optimization models for long-term investment planning in a pavement network

    During the period 2004 - 2006, evaluations executed by the National Laboratory of Testing Materials and Structural Models (LanammeUCR) at the University of Costa Rica indicated that there was no a significant improvement with the road network. This conclusion leaded to establish this research based on the principles of Asset Management. A long term strategic investment plan (20 years) was developed for pavement structures for the maintenance district 1-9 (Heredia) in Costa Rica.
    Several investment scenarios were estimated, including the budget assigned by the government for 2007.
    For the pavement structures it was used inventories such as visual distresses, roughness (IRI), deflection data (FWD), traffic (AADT), layer and material characterization data. A Pavement Condition Index (PCI) was estimated based on deflections and roughness. Also it was used deterioration curves, selection of treatment windows, and economical analyses.
    By using Woodstock Linear Optimization tool (Remsoft Inc.), several investment plans were developed at the strategic level. Some of these scenarios included different annual budgets, and also the budget required to eliminate the bad roads in 15 years was estimated. The solution includes the type of treatments that need to be applied in specific locations on a year basis and its costs. These results follow the Asset Management principle: to maximize the investment and allocate the resources at the right time, at the right asset, at the right moment, with the objective of maintaining a good level of service.
    As a result, by using long term investment plans more effective decisions can be taken to recover our assets efficiently. It also can be used for accountability and request of budget. Finally, the key success to implement an Asset Management System is to address the structure of the organization, human resources and technology.

  5. High-performance road network assessment equipment

    n order to answer to the express need to establish procedures capable of offering support to the eventual creation of a Pavement Management System in Costa Rica, the Evaluation of the National Road Network Unit (LanammeUCR) developed a series of methodologies with the use of high performance equipments. With these methodologies it was possible to establish a systematic evaluation process and technical objective criteria to realize an evaluation of the functional and the structural capacity, skid resistance and the level of superficial deterioration for the whole National Road Network. Once implemented these methodologies it was possible to generate and maintained a database with detailed information of the general condition of the road network, which could be use as a technical base for the generation of investment plans and intervention strategies.

  6. Mix design to evaluate its uniaxial compressive strength and permeability

    Pervious concrete maybe used in low transit pavements, condominium and residential streets, or parking lots, among others. It is a mixture of cement, water and coarse aggregates. Strength and permeability are pervious concrete’s most important characteristics and must be correctly balanced to attain adequate performance.This study analyzed the effect of water/cement ratio, coarse aggregate/cement ratio, and the type of coarse aggregate used (maximum size and source) over 19 pervious concrete mixes. Behavior trends showing the relation between the stated properties and the uniaxial compressive strength and permeability of the material were observed from the results obtaine