ROADS

Author: PRIETO MUÑOZ JORGE NEVARDO.
Year: 2005.
University: POLITÉCNICA DE MADRID [www.upm.es].
Place of defense: E.T.S. INGENIEROS DE CAMINOS, CANALES Y PUERTOS.
Place of preparation: ESCUELA TÉCNICA SUPERIOR DE INGENIEROS DE CAMINOS, CANALES Y PUERTOS.

Summary: The reflection of cracks in bituminous mix placed on pavements or cracked or covered with layers together has been and remains a major problem in the engineering flooring. The inconvenience caused by the reflection of cracks are diverse: the increasing deterioration of the bituminous layer increasing maintenance costs, allowing the entry of water through the cracks causing loss of structural capability of the firm. Similarly, desmejoran regularity surface, increasing operating costs and reducing the safety of road users. The phenomenon of reflection cracking has been studied from various approaches, some authors classified into four groups: studies numerical methods, development of models for empirical experiments in laboratory and field experiments. In experiments in the laboratory, according to research publicadas- have been used equipment originally developed for other evidence, and also have developed prototypes with specific application to the study of the reflection of cracks in bituminous layer. However, until now unknown to the existence of a test to study the reflection of cracks that is done in various laboratories, which is recognized by the scientific community, technical and academic, and is commercially available to be purchased and used regularly by laboratory materials for roads and entities, such as universities, interested in research on the topic. In this Doctoral Thesis established the goal of developing a test that can be used in laboratories to study materials for road resistance of bituminous mix a reflection of cracks, as well as the effectiveness of the systems antirreflexión. The prototype to test grew out of the wheel load used in the test track laboratory; of equipment commonly used in a laboratory materials for highways was seen as the most suitable to simulate the effects caused by the transit of heavy goods vehicles in the process of reflection cracks. Also from the perspective of disseminating the test, equipment test track exists in various laboratories, which can economically facilitate the acquisition and use of equipment developed in this Doctoral Thesis. The prototype developed in this research simulates all three types of variations in the cracks and joints of the firm, causing cracks in the reflection of the bituminous layer: -Abertura the cracks and joints by declines in temperature -Abertura the cracks and boards by bending firm DCI relative vertical edges of the board or crack Additionally, when you try a low temperature -5 or C-tested in the test tube is the most critical environmental conditions for a mixture bítuminosa exposed to the phenomenon of the reflection of cracks. With the prototype developed experimental studies were conducted to determine the sensitivity of the test in relation to the magnitude of the deflection and speed of opening of the seal or crack. The results indicated that the test is sensitive for the two factors, which will simulate various structural conditions in the laboratory's strong -modificando the magnitude of the deflection simulated in the prueba- and various climatic conditions -modificando speed opening of the crack, a result of declines in temperatura-. We also conducted a comparative study were tested five types of test tubes with some geotextile as a system antirreflexión-. The results indicated that the evidence is consistent and that enables a relative ranking of the materials tested, according to their resistance to reflection cracking. Developed prototype and studied 8 his sens 62d ibilidad and consistency produced a draft standard for the test. Among other things, the standard includes the purpose and scope of the test, equipment and materials needed, and the procedure for conducting the test. Finally, since the precision is a very important element to characterize a laboratory test was developed a proposal for a pilot study to determine the accuracy of the test developed in this research. This study is a future investigation to be carried out into the line of inquiry in reflection of cracks being developed in the Laboratory of Roads of the Polytechnic University of Madrid, and which forms part of this Doctoral Thesis, partially financed by the Ministry of Science and Technology of Spain. Keywords: Reflection of cracks, laboratory testing, Asphalt mixtures.