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

In the present paper an evaluation of scour problems bridges of the Colombian National Highways has been developed; based on the principal inspection and inventory module of the Colombian Bridge Administration System (SIPUCOL), which has been implemented since 1996 by the National Highways Institute (INVIAS). SIPUCOL has been an essential tool to maintain security and functionality of Colombian bridges. This article presents the amount, evolution and classification of damages, based on visual inspections, maintenance, studies performance and rehabilitation works. In this document it has been included all the collapsed bridges which main cause of collapse has been scour. To prevent bridges failure risks, taking into account that scour is a complex problem, some recommendations have been made about the inspection methodology, the study’s quality and the analytic research implementation.

What is a Road Safety Audit? It is a technical evaluation carried out by a team of auditors specialized in road and bridge safety, aimed at identifying infrastructure-related factors that may contribute to traffic accidents or increase their severity, as well as conflicts in the operation of vehicles and other road users.

Many bituminous layers in pavements fail for associated problems with damage by material aging rather than damage caused by vehicle loads. In order to improve this situation, many solutions in the design that often consist in increasing the content of asphalt in the mixtures to achieve a thicker asphalt layer wrapping aggregates and to reduce the percentage of voids. Nevertheless, an excess of asphalt could generate asphalt exudation and lack of stability, as well as an increase in cost of the product.   Usually, asphalt road pavement specifications do not consider in a good way the factor of aging in establishing its prescriptions, insisting on characterizing the behavior of asphalts set against the mechanisms responsible for the "hardening by age", using empirical trials of simulation that only test the material working alone, not including the interaction that is produced with the other components of the mix.  The advantages of using additives (fílleres) specially formulated to improve resistance to aging is well known, however, many times other associated concepts are not considered but they affect the two-phase system fíller-asphalt and also have influence on a series of fundamental characteristics of the mixtures.   The universities de la Plata, Argentina, and technical college of Cataluña, Spain, carried out a joint research with the goal to understand some phenomena related to the aging of the asphalt and to establish guidelines of design that contribute to optimize the resistance of deterioration of the bituminous mixtures. In addition, new procedures of research were employed; the functional method "Universal of characterization of binders" (UCL®), reologic tests with the dynamic shear reometer (DSR) and techniques of macromolecular analysis as the chromatography by permeability of gels (GPC) and the spectroscopic infrared.  This first part of the study presents, a synthesis of the results obtained utilizing the universal method of characterization of binders, UCLⓇ. 

Being water one of the most detrimental natural agents affecting the maintenance of the physical and mechanical properties of pavements throughout their service life, the main focus of this study is to address the effect of water action on asphalt mixtures under conditions of induced moisture, using the theoretical principles proposed in the Modified Lottman Test (AASHTO T-283/89). The Amazon region, and particularly the State of Pará, was selected for material sourcing due to its high annual rainfall levels, ranging from approximately 2500 mm to 3000 mm. This high precipitation influenced the choice of materials used to formulate the mineral skeleton of the asphalt mixtures (senior granite aggregate, quartz sand, and limestone powder). The petroleum asphalt cement used (CAP 50/70) was sourced from the Lubricants and Petroleum Derivatives Refinery of the Northeast, located in the State of Ceará (LUBNOR/CE). A comparative analysis was conducted between asphalt mixtures produced using gradation curves formulated through the Fuller or Talbot Equation (referred to as theoretical curves) and those used in Brazil, such as the gradation curves from the National Department of Transport Infrastructure (DNIT). The DNIT Curve C was specifically explored, as it is widely used in the region for paving services.The study demonstrates the damaging effect of water in asphalt mixtures when present in the interstices of their composition, particularly under conditions of high thermal gradient.

This article presents a structural reliability evaluation of the main components of one of the most important steel bridges on Colombia’s National Road Network. The assessment, based on structural reliability techniques, was supported by both field and office activities, including geometric surveying, mechanical testing, traffic counting, load testing, structural model calibration, instrumentation, monitoring, and numerical simulation. For the monitoring process, an electronic data acquisition system was implemented using a multipoint master-slave network (RS-485), incorporating signals from ten (10) strain gauges installed on the main structural elements of the bridge over a fifteen-day period. The monitoring allowed for a detailed analysis of the actual stress demands generated by traffic on the main bridge elements, which were compared against the design load (C40-95) specified by the Colombian Seismic Bridge Design Code (CCDSP). Significant overloads were identified on certain elements, posing safety concerns that require immediate corrective actions. Additionally, failure probabilities were calculated for some structural components, revealing values outside acceptable safety thresholds, thus compromising their stability and increasing the associated risk.

The Texas Department of Transportation (TxDOT) has recently established Hamburg Wheel Tracking Device (HWTD) specification criteria for Superpave mixtures. This has introduced a performance related feature to an otherwise volumetric mix design approach structured to ensure the rutting performance of asphalt mixtures. The Superpave mixture design procedure is itself geared towards the production of ne resistant mixtures. This, together with the new HWTD performance criterion tends to promote mixtures with lower binder contents. While this is advantageous for rutting resistance, there are reports that these mixtures are prone to cracking, which is becoming the single largest problem for asphalt pavements in Texas.   In an attempt to produce mixes with higher binder contents to alleviate cracking problems, TxDOT has investigated the possibility of modifying the current design criteria established for Superpave mixtures, Initial research investigating the influence of lowerning the 4 percent volds in the mir anterion to 3 and aven 2.5 percent has resulted in increased optimum binder contents but has proven detrimental for those mixtures using softer binders. The Superpave misture design method does not account for mixes with stiff polymer-modified asphalts currently being used. Furthermore, the concentration of coarse aggregate in the mix and the influence of nominal maximum aggregate size are not accounted Ar  The study reported in this article outlines a reliability-based mixture design procedure based on a performance related approach geared towards determining revised N compaction levels to increase binder contents in asphalt mixtures without compromising rating performance An extensive experimental program has been devised to investigate the performance characteristics of asphalt mixtures designed using the revised N levels and to account for the nominal maximum aggregate and the concentration of coarse aggregate in the mix, The procedure found strong support for decreasing current levels under most conditions, except when high-volume facilities in war environments. The number of design gyrations for most condition in Texas could be lowered to 75 to 85 from improved fatigue performance, without significant loss of rutting resistance. 

The modification of asphalts with polymers from different varieties and origins is one of the most important tendencies of the present highways construction industry.  Polymer contributions to reological properties improvement of the asphalts have been extensively studied. However, each time that a new product is on the market, it is necessary to carry out an exhaustive analysis of the improvements that the polymer would be able to cause to the asphalt.  The asphalts classification methodology by performance has been constituted in the fundamental tool of analysis of asphalts; however, in the case of modified asphalts its rank of application is very limited, just as has been determined up to now. The main problem is that modified asphalts with different polymers can have the same performance, without being able to discern among the individual contribution of each polymer that would lead to choose the polymer that maximize the characteristics of the modified asphalt.  Today, the protocols established in the NCHRP 9-10, are implementing a series of new trials that will be able to consider which, of various modifying agents, can cause better reological asphalt conditions This: NCHRP 9-10 contribution is fundamental to determine with what polymer will be the binder performed better, given that in many cases, the selection of a modifier is based only in financial criteria, with a same performance. With this technology update, it will be able to do financial analysis considering how useful it will be to the highway.  This study was born with the main objective to analyze different polymers and its effect on base asphalts AC-20 and AC-30, and to determine the performance that each one has, with different polymer concentrations This information can be of great importance for highways builders to choose adequate options that the market has. The result of the first phase of this project can be found in the report LM-PL-PV-IN-18 -02 a.  In this second phase, the results of the analysis of the AC-30 asphalt are presented, mixed with 6 different modifying agents, and the classification of the final product will be performed by means of the classification by performance primarily, and subsequently, by means of the trials indicated by the protocol NCHRP 9-10: creep, fatigue and zero cut viscosity (Zero Shear Viscosity, ZSV, by its acronyms in English.

The Company TNM - Technology and Management has developed a system of road and public space management directed to the administration of the urban road network, of areas destined to pedestrian public space, as well as pedestrian and traffic bridges of the city of Bogota Colombia, which at the same time includes the pavements deterioration models by means of periodic measurement of variables that influence in that deterioration. The design of this system is oriented to provide a systematic tool that permit to the Local Administration to determine the scope of the actions of maintenance and rehabilitation on the road infrastructure and urban public space at any time, to prioritize projects and to optimize the available resources, looking to maintaining a level of service given in terms of its structural and functional condition. The main intake to carry out the management on the infrastructure of road network consists of the data of inventory and diagnosis relieved by diverse consultants, during the last 5 years, obtained using last generation technologies such as the falling weight deflectometer (FWD) and the international roughness index (IRI) This information a property organized and stored in a database. Similarly, the inventory and diagnosis contains the associated infrastructure of public space, such as, decks, bus stops, pedestrian crossings, bike paths and general urban funiture. Regarding the bridge information, there is no inventory of them yet, but they have defined the variables to collect to carry out an adequate management for this infrastructure. 

In studies involving asphalt mixtures—such as structural pavement design, service life estimation, suitability analysis, or mix design—it is essential to know the traffic volume that uses the roadway, expressed as AADT (Annual Average Daily Traffic), which represents the average daily volume over a full calendar year. This value averages out traffic volumes generated by non-regular or intermittent activities (such as study, work, vacations, leisure, etc.). Due to this variability, continuous traffic counts are required to accurately determine the AADT, which often involves large-scale efforts and considerable resources. In tactical and operational tasks (medium- and short-term), or in immediate-response situations where sufficient resources or data are not available, this becomes particularly challenging. For this reason, sporadic or short-term traffic counts are often used, and due to the lack of historical data, these are typically extrapolated subjectively by professionals who may not have a direct background in traffic engineering. This introduces a high degree of uncertainty, ultimately undermining the validity of other parameters that are otherwise based on accurate and reliable data, resulting in extremely low confidence levels in subsequent applications. For these reasons, this master’s thesis aims to develop, disseminate, and apply an objective methodology for extrapolating short-term traffic counts into AADT values. The methodology is intended for application across a broad homogeneous region in Argentina, specifically the provinces of Buenos Aires, Santa Fe, Córdoba, Entre Ríos, and La Pampa.

The addition of industrial products such as rubber and plastic may constitute a pavement structure by providing asphalt mixes with better mechanical behavior and more durability. We have to be conscious that we live in the culture of using and throwing away, and in the trash of each day there are many resources that we are wasting, it is important for all of us to put in action the three “R”, reduce, reuse and recycle. By carrying out this research project we hope to achieve a reduction in the solid waste residues and additionally to improve the performance of the pavements in Colombia. In this investigation of asphalt mixtures modified with rubber and plastic, we made the dynamic characterization of the mixture with the optimal addition of plastic origination from markets of milk bags and of rubber originating from used tires, achieving a reduction on rutting of 8%, an increase of the dynamic modulus of 14%, which means for a mechanistic design of pavements an increase of 25% in durability.