Caracterización mecánica de hormigones autocompactantes reforzados con fibras de acero

El hormigón autocompactante reforzado con fibras de acero presenta simultáneamente las ventajas de los hormigones autocompactantes y de los reforzados con fibras. Se consigue un material de altas prestaciones con mayor tenacidad y ductilidad. En este trabajo se ha estudiado el comportamiento mecánico de un hormigón autocompactante reforzado con fibras de acero. Se han realizado ensayos a compresión, tracción y flexión a distintas edades; así como ensayos no destructivos (medida de la velocidad de ultrasonidos e índice esclerométrico). Los resultados muestran la variación de la respuesta del hormigón con el tiempo y la diferencia existente con hormigones tradicionales

Caracterización mecánica experimental de un hormigón ligero estructural = Experimental mechanical characterisation of a structural lightweight aggregate concrete

The self load of the structure is usually similar even bigger than any other load load which a structure carries. Due to this fact a number of structure are inefficient. The replacement in concrete of normal aggregate by lightweight aggregate reaches a markedly reduction of the concrete weight. The mechanical behavior of a lightweight aggregate concrete is analyzed in this paper. A number of tests have been done at different ages. These results have been compared with the predicted mechanical values of some regulatio

Experimental mechanical characterisation of a estructural lightweigth aggregate concrete acording to EC-2

The self load of a structure is usually higher than the loads it has to carry. It means that these kind of structures are quite often inefficient. The replacement in concrete of the normal aggregate by other lighter materials leads to a significant fall in the concrete weight. The normal aggregate has been replaced by lightweight aggregate since Roman Empire Ages. It has let singular buildings as Agripa's Pantheon or the Coliseum in Rome. Teh evolution according to the age of the compression and tensile strength and the Elastic Modulus in a Lightweight Aggregate Concrete (LAC) has been analysed in this paper. The concrete was produced by LAFARGE. Its commercial name is THERMEDIA. The experimental researches has been compared with predicted values by EC-2

Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)

Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters. Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs). Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001). Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio

Estudio experimental comparativo del comportamiento a flexión de un hormigón ligero estructural frente a un hormigón convencional

Una buena parte de los cálculos realizados en hormigón armado corresponden al estudio de elementos a flexión. El comportamiento del hormigón convencional (HC) ante este fenómeno está ampliamente estudiado. El hormigón ligero estructural (HLE) presenta ventajas evidentes por la reducción del peso frente al HC. Si bien se ha investigado al respecto, los estudios para este material están lejos de los realizados para el HC. Este trabajo pretende ampliar el conocimiento del comportamiento del HLE frente a la flexión para contribuir a su utilización en todas las situaciones en donde su empleo supone una clara ventaja frente al HC