The behavior of sands subjected to diverse loading conditions has been the object of many studies in recent decades. Constitutive models that are able to simulate the behavior of sands have been developed based on critical state theory. Researchers have shown that the defining parameters of the critical state line (CSL) can be obtained by performing drained and undrained tests on samples with different initial densities. This work aims to verify the drained and undrained behavior of aeolian sand from Natal, Brazil, based on critical state soil mechanics. Drained and undrained tests were performed on samples with initial void ratios equal to 0.7 and 0.8, which correspond to loose and medium-dense relative densities, respectively. Samples with both void ratios were subjected to confining stresses equal to 50, 100, 200 and 300 kPa. The results show that the critical state line can be defined from the drained and undrained tests performed on samples with loose and medium-dense initial relative densities. The parameters from the critical state theory were obtained using projections on the planes p'-q and lnp' -v. The critical state friction angle is equal to 31.5°, and it is compatible with clean and uniformly graded sands with angular to subangular features and composed mostly of quartz. The obtained M, G and l values are equal to 1.26, 1.863 and 0.03, respectively. The obtained parameters will be used in analyses and numerical simulations of the geotechnical structures built on aeolian dune deposits from the city of Natal, Brazil.

Norte state (RN). What differed from one result to another was the value of the adjustment coefficient (x). Rios et al. (2013) showed that parameter x depends on the grain size and mineralogy of the soil. Baldovino et al. (2018) studied the treatment of the Guabirotuba geological formation soil (Paraná Basin, Brazil) by lime addition for improve its usability in pavement construction, in protection of hillsides and slopes, or as shallow foundation support. It was observed that the q t /q u ratio is between 0.17 and 0.2 in relation to the curing time, and an exponential relation exists between them. Baldovino et al. (2020b) optimized and compared the behavior of soil-cement compacted blends against several molding and climate conditions under optimum compaction and non-optimum compaction parameters. The results show an increase in strength and durability properties of the blends when cement Abstract Soil behavior is influenced by the void ratio and bonds between grains. The aim of this study was to describe the strength behavior of an aeolian sand from the dunes of Natal, Brazil, artificially cemented in unconfined compression tests. The influence of cement content and moisture on molding and the validity of using the void/cement factor in estimating unconfined compression strength (UCS) were assessed. Tests were conducted with samples using three molding moisture contents (6, 9 and 12%), four cement contents (2.5, 5.0, 7.5 and 10%) and a void ratio of 0.6 (D r = 95%). The results showed that unconfined compression strength rises with increase in cement content and decreasing in molding moisture. The void/cement factor proved to be a reliable parameter in predicting the behavior of sand from Natal for the dosage of soil cement.