Evaluación de la capacidad resistente (CBR) en bases granulares de materiales procedentes del rio Paute

Abstract

In road construction, pavements are composed of layers whose strength decreases with depth. The layers on which the wearing courses are laid are called "Base Course". In Ecuador, the characteristics are established in the General Specifications for the Construction of Roads and Bridges, 2002 Edition, Sections 404 and 814. During quality controls in road construction, appreciable variations are obtained in the results of granulometric tests (INEN 696), although the aggregates present continuous granulometry and remain within the granulometric limits. However, the value of the California Bearing Rate, CBR (ASTM D1833) upper than 80% obtained in the laboratory, is achieved only with a granulometric spindle. The study revealed the variations of the CBR in granular materials, depending on the granulometric composition. For this purpose, mixtures of materials were made in the laboratory (materials obtained from the crushing process), that represent the granulometric curves of Class 1B base materials (upper, intermediate, and lower limit of the granulometric range of Table 404-1.1 - MOP 2002). The results showed that the difference between the maximum unit weight values is negligible. In the CBR tests, however, there was a significant difference between the results obtained at the upper and lower granulometric gradation limits.