No abstract

Marine clay is commonly found worldwide and is challenging to work with from a geotechnical and geoenvironmental perspective due to its diverse characteristics, such as high compressibility and sensitivity. There is therefore a need to seek effective treatment solutions that are less environmentally harmful than traditional methods. The aim of this research study was to assess the performance of marine clay treated with a binder incorporating Portland cement, hydrated lime and copper slag. Unconfined compression and split tensile tests were carried out to assess the distinct binder content effects and to correlate those responses with the porosity/binder index. Moreover, scanning electron microscopy was conducted to study the microstructure of the mixes containing copper slag. The results showed that the addition of lime, the dry unit weight and the curing period were the most influential factors regarding the strength of the mixtures, in that order. In addition, good correlations were obtained between the strength and the adjusted porosity/binder index for all mixtures.

No abstract

No abstract

Failures of tailings dams, primarily due to liquefaction, have occurred in Brazil in recent years. These events have prompted the Brazilian government to place restrictions on the construction of new dams, as iron ore tailings deposited behind upstream dams by spigotting have been shown to have low in situ densities and strengths and are prone to failure. This work proposes a new trend for tailings disposal: stacking compacted filtered ore tailings–Portland cement blends. As part of the proposal, it analyses the behaviour of compacted iron ore tailings–Portland cement blends, considering the use of small amounts of Portland cement under distinct compaction degrees. With the intention of evaluating the stress–strain–strength–durability behaviour of the blends, the following tests were carried out: unconfined compression tests; pulse velocity tests; wetting–drying tests; and standard drained triaxial compression tests with internal measurement of strains. This is the first study performed to determine the strength and initial shear stiffness evolution of iron ore tailings–Portland cement blends during their curing time, as well friction angle and cohesion intercept. This manuscript postulates an analysis of original experimental results centred on the porosity/cement index (η/Civ). This index can help select the cement quantity and density for important design parameters of compacted iron ore tailings–cement blends required in geotechnical engineering projects such as the proposed compacted filtered iron ore tailings–cement blends stacking.