Abstract The use of slate waste can help to reduce the impacts caused to the environment due to the decrease of the appropriate disposal areas and the disordered consumption of raw material. This article presents an analysis of the Resilient Modulus (RM) and the California Bearing Ratio (CBR) of this waste in mixtures with clayey soil. To analyze variations in RM and CBR due to the increase in the slate waste content, tests were carried out on reference mixtures (REF) and mixtures containing slate waste (SLT). The tests were carried out for mixtures of granular material (gneiss for REF and slate waste for SLT) and clay soil, containing different levels of granular materials (50%, 60%, 70%, 80% and 90%) It was observed that the values of Resilient Modulus and California Bearing Ratio of the SLT mixtures increased 62.8% and 127.0% with the addition of the slate waste between the SLT 50/50 and SLT 90/10 mixtures, respectively. This behavior was similar to that presented by the REF mixtures, which increased 125.0% in RM and 60.1% in CBR for the same addition of granular material. The results obtained indicate that the mixtures containing slate waste presented RM and CBR similar to those of conventional materials (such as the REF mixtures) used in layers of sub-base and the base of pavements. Finally, it was concluded that the relationship between RM and CBR is non-linear for both mixtures (REF and SLT) in function of granular material addition.

Abstract This article presents a study on the performance of semi-empirical methods based on the Standard Penetration Test (SPT) for the prediction of bearing capacity already disseminated in the practice of Brazilian Foundation Engineering (Aoki and Velloso, 1975; Décourt and Quaresma, 1978, 1996; Teixeira,1996), together with the recent method proposed by Pereira (2020), and the theoretical method known as a Method (disseminated around the world). These were applied to precast concrete piles based on sandy clay in the Uberlândia-MG region. In the performance analysis, the ultimate shaft and tip resistances and the bearing capacity values, which were utilized as references, were mobilized in the dynamic loading tests performed on ten piles. The results of these tests were compared with those obtained using the mentioned methods. In general, both methods yielded robust results, with relatively accurate predictions, except the a Method, which was found to perform below the semi-empirical methods considered. The research still highlights the need for discretion in the application of semi-empirical/theoretical methodologies because there are certain scenarios wherein these methods can yield inaccurate results.