Estado del arte del uso de nano materiales en suelos para construcción de carreteras

Nano materials are becoming more and more relevant in the construction of civil works, since they can be used as additions or additives to improve and stabilize asphalt concretes, hydraulic concretes, fine soils at the level of subgrade, sub-bases, bases and even for filters in water treatment. The present article intends to collect the different experiences in the use of nano materials, in order to stabilize or improve the mechanical and geotechnical properties of soils used in road construction, especially what has to do with the manufacture of nano fibers for use in soils; finding that its use in the field of roads is to be investigated and developed with different types of solutions, as the most studied are the carbon nano fibersLos nano materiales toman cada vez más relevancia en la construcción de obras civiles, ya que se pueden usar como adiciones o aditivos para mejorar y estabilizar concretos asfalticos, concretos hidráulicos, suelos finos a nivel de sub rasantes, sub bases, bases e inclusive para filtros en el tratamiento de aguas. El presente artículo pretende recolectar las distintas experiencias plasmadas por la ciencia en el uso de nano materiales, con el fin de estabilizar o mejorar las propiedades mecánicas y geotécnicas de los suelos usados en la construcción de vías, sobre todo lo que tiene que ver con la fabricación de nano fibras para uso en los suelos; encontrándose que su uso en el campo de las carreteras está por investigarse y desarrollarse con diferentes tipos de soluciones, pues las más estudiadas son las nano fibras de carbon

Rheological behaviour of clays in plastic state

Clayey soils exhibit viscoelastic behaviour in the plastic state, implying simultaneous retentive and dissipative mechanical properties as well as strain rate dependent properties. Such response is partially captured by the socalled Atterberg plastic limits. A more comprehensive evaluation of the mechanical response of this type of soils in the plastic state can be obtained by testing in a dynamic shear rheometer. Clayey soils consisting of different proportions of kaolin and bentonite and different water contents were subjected to dynamic shear tests to measure their rheological properties. All tests were performed with a constant strain amplitude of 10%, a fixed range frequency sweep (0.1 Hz to 100 Hz) and a constant temperature of 20°C. The results show that the complex shear modulus has an inverse relationship with the soil water content and a direct relationship with the plasticity index. Moreover, the phase angle increases slightly and then decreases suddenly as the frequency increases. The complex shear moduli obtained by dynamic tests were compared with the oedometric moduli estimated by correlations and showed satisfactory trends between them. The study contributed to the understanding of the complex behaviour of soils in the plastic state. Although the mechanical response of these materials is affected by some factors, the plasticity limits were consistent with the complex moduli under analogous conditions of strain and frequency