The hydration process of Portland cement triggers reactions of stabilization of minerals from the contact of the clinker with water, which is the Hydrated Calcium Silicate (C-S-H), the Etringite (3CaO.Al2O3.3CaSO4.32H2O) and the Portlandite (Ca(OH)2). In order to understand the effects of the evolution of hydration in cement, it is possible to apply non-destructive tests. In this context, the objective of this work is to evaluate the influence of the type of cement, the curing age, of the format and humidity of the test specimens of concrete in the ultrasonic pulse velocity (UPV). In order to do that, 36 cylindrical test specimens (10 x 20 cm) and 9 cubic ones with 25 cm of edges, with mix proportion of 1:2,7:3,2 (cement/sand/gravel), water/cement ratio of 0.58 and three types of Portland cement (CP II-Z-32, CP IV-32 RS and CP V-ARI) were molded. With data obtained it was possible to correlate the increase of concrete strength along time (at ages of 7, 14, 28, 70 and 91 days) with the increase of the ultrasonic pulse velocity. Besides, it was possible to prove the direct influence of the concrete moisture and of the degree of hydration in the UPV. The shape of the test specimen generally had no influence on the results, except in the case of cement CP V ARI.

O setor minerário brasileiro representa uma parcela importante na geração de recursos através da comercialização no mercado nacional e internacional. Este setor movimenta outros setores através suprimento da matéria-prima extraída, como é exemplo das indústrias da construção civil, automobilística, aeroespacial e outras. Muito embora sua importância seja relevante e estratégica na economia, a geração de resíduos é significativa e para tanto é necessário que sejam viabilizados métodos de disposição destes materiais obedecendo as restrições ambientais, sociais e econômicas. Com isso, diante ao enorme vulto de materiais residuais gerados, as barragens de contenção rejeitos minerais representam uma das técnicas mais optadas por mineradoras e geotécnicos. Logo, este artigo tem como proposta fornecer informações quanto a conceitos, métodos construtivos, técnicas e outros aspectos que envolvam o assunto barragem de contenção de rejeitos a partir de uma revisão literária.

This article presents an experimental study performed to evaluate the volume of material released from the reservoir during a tailings dam failure event using models. To verify the influence of the parameters related to the breach geometry and the undrained shear strength (Su) in a failure event, 20 scenarios were simulated considering the absence of water in the reservoir. The material used to simulate tailings was bentonite, due to the similarity between the properties of the mud and mineral tailings sludge. Geometry and undrained shear strength were adjusted considering a scale factor of 1: 500. Regarding the studied parameters, the geometry of the breach was based on data from literature, whose lateral slopes were 0.50 H: 1V, 0.51 H: 1V and 0.5467 H: 1V in the trapezoidal breaches and 1: 1 (L / H = 0.97) and 1: 1 (L / H = 1.1) in the rectangular ones. The undrained shear strength ranged from 0.030 to 0.20 kPa. The results allowed to conclude that the mobilization of material increases with the average aperture width of the trapezoidal breach, being this the distinct behavior in rectangular breaches. Although the rectangular breaches had smaller average widths compared to the trapezoidal breaches, their base widths were larger and it is possible to infer that the mobilized volume depends on the geometry and the average width of the breach.

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