A Unique Relationship Determining Strength of Silty/Clayey Soils - Portland Cement Mixes

This technical note advances the understanding of the key parameters controlling unconfined compressive strength (qu) of artificially cemented silty/clayey soils by considering distinct moisture contents, distinct specimen porosities (η), different Portland cement contents and any curing time periods. The qu values of the specimens moulded for each curing period were normalized (i.e. divided) by the qu attained by a specimen with a specific porosity/cement ratio. A unique relationship was found, establishing the relationship between strength for artificially cemented silty/clayey soils considering all porosities, Portland cement amounts, moisture contents and curing periods studied. From a practical viewpoint, this means that, at limit, carrying out only one unconfined compression test with a silty/clayey soil specimen, moulded with a specific Portland cement amount, a specific porosity and moisture content and cured for a given time period, allows the determination of a general relationship equation that controls the strength for an entire range of porosities and cement contents, reducing considerably the amount of moulded specimens and reducing projects development cost and time

Artificially cemented sand under multiaxial loading

Distinct improvement techniques can be used when civil engineering structures are to be built on soils that do not present suitable mechanical characteristics. The soil improvement techniques can vary from compaction to chemical and mechanical stabilisation. This work focuses on the specific case of granular soils treated with low amount of cement. The study aims to investigate the behaviour of a cemented sand under multiaxial loading conditions. A series of advanced tests on reconstituted cemented sand were conducted in a Cubical Cell Apparatus (CCA) and exploration of material response including failure limits under different constant stress paths (θ = 0° and θ = 120°) in the octahedral (π) plane were performed. Results showed strength is higher in vertical direction than in horizontal direction

Abscesso subdural ao nível da cauda equina: relato de um caso

É relatada a observação de um paciente de 42 anos, com paraplegia flácida devida a abscesso subdural ao nível da cauda equina. É realçada a pobreza de alterações sensitivas e esfincterianas neste caso e enfatizada a importância da cirurgia para obtenção de bons resultados