The Cemented Crushed Stone (C2, as the South African Classification) was widely used on the main high-traffic Brazilian highways in the 1970s and 1980s. However, it presents several limitations for its use in the road work related to the properties of the material and its almost fragile nature, since as soon as the large variations in the tensile strain take place along the loading cycle, critical and accelerated degradation also occur, leading to material fatigue distress. Several factors stand out as probable causes for the intense and rapid process of fatigue, the main ones being: granulometry, cement content, and moisture content. In this way, a study was carried out to analyze the mechanical properties of C2 based on granulometry variation in relation to the cement and moisture content. It was noted that the mixture with the best joint performance was the one with the highest percentage of the sand fraction, highest cement content, and molded below the optimum moisture. Some recommendations were made for the mix design of C2, such as the definition of a granulometric range that considers the analysis of the aggregate large/small ratio in order to obtain a greater gain of maximum dry specific mass, as well as the use of cement contents above 4%, since below that the cementation will be insufficient. In addition, optimized ratios (aggregate + cement + water) should be defined by performing the mechanical analyzes listed in this paper, in order to select the best performance mixture to be applied in the road works.
Preliminary and complementary geotechnical investigations allow to obtain important information about the subsoil layers. However, in daily practice, this step is usually neglected. This problem becomes harder when there are layers of soft soils in the subsoil, due to the particularities of this kind of soil. Metropolitan Region of Aracaju (MRA) have few recorded data about their soft soil deposits, which difficult geotechnical design. Hence, this study aims to perform the geotechnical characterization of some soft soil deposits existent in the MRA and georeferencing these deposits, using a Geographic Information System (GIS). The results obtained show that the studied deposits have a medium plastic to very plastic behavior (PI ranging from 8.00 to 33.00). Values of natural moisture content were considerably lower than those obtained in other Brazilian states (between 29% and 84%), possibly due to the influence of the sand lenses. As for the activity, the MRA clays are predominantly inactive. Furthermore, the analysis of the quality of samples made it clear that is difficulty to collect undisturbed soil samples in these deposits. In the future, complementary research needs to be developed to increase the knowledge about these soft soil layers.
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