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The effect of shrinkage cracks on the load bearing capacity of steel-fibre-reinforced roller-compacted-concrete pavements Materials and Structures / Materiaux et Constructions, 2015; OnlinePubl:1-19

Loss of productivity through on-site delays and disruptions is a significant problem in the construction industry. This can be caused by workforce, materials, and equipment clashes. A major need for the industry is to improve construction logistic efficiencies for materials and equipment from manufacture to the point of use by the workforce. The authors investigate the effectiveness and efficiency of integrated construction supply chain logistics (ICSCL) using 4D Building Information Models (BIM), via three information streams: literature, a case study of the Elephant and Castle project (E&C), and a survey from UK construction professionals. The results illustrate, although BIM of various levels is currently in use throughout the UK, 4D BIM for ICSCL is not extensively utilised due to an absence of strategy, perceived costs of IT, and training requirements. That use could potentially add value with a trusted supply chain and disciplined planning using a multiple stream logistic model.

ABSTRACT:Fracture of steel-fibre-reinforced-concrete occurs mostly in the form of a smeared crack band undergoing progressive microcracking. For FE modelling and design purposes, this crack band could be characterised by a stress-strain (σ-ε) relationship. For industrially-produced steel fibres, existing methodologies such as RILEM TC 162-TDF (2003) propose empirical equations to predict a trilinear σ-ε relationship directly from bending test results. This paper evaluates the accuracy of these methodologies and their applicability for rollercompacted-concrete and concrete incorporating steel fibres recycled from post-consumer tyres. It is shown that the energy absorption capacity is generally overestimated by these methodologies, sometimes up to 60%, for both conventional and roller-compacted concrete. Tensile behaviour of fibre-reinforced-concrete is estimated in this paper by inverse analysis of bending test results, examining a variety of concrete mixes and steel fibres. A multilinear relationship is proposed which largely eliminates the overestimation problem and can lead to safer designs. RESUMEN:Comportamiento a tracción posterior a la fisuración del hormigón reforzado con fibras de acero compactado con rodillo para el diseño y modelado EF. La rotura del hormigón reforzado con fibra de acero se produce principalmente en forma de una banda de fisuración que sufre progresiva microfracturación. Para el diseño y modelado EF, esta banda se puede caracterizar por una relación tensión-deformación (σ-ε). Para fibras de acero industriales, existen metodologías (RILEM TC 162-TDF 2003) que proponen ecuaciones empíricas para predecir una relación σ-ε trilinear a partir de resultados de pruebas de flexión. En este artículo se evalúa la precisión de estas metodologías y su aplicación para hormigón compactado con rodillo y hormigón reforzado con fibras de acero recicladas provenientes de neumáticos usados. Se demuestra que estas metodologías generalmente sobreestiman la capacidad de absorción de (hasta un 60%) tanto para el hormigón convencional como para el compactado con rodillo. En este artículo se calcula el comportamiento a tracción del hormigón reforzado con fibra mediante el análisis inverso de resultados de pruebas de flexión de varias composiciones de hormigón y fibras de acero. Se propone una relación multilinear que elimina en gran medida el problema de sobreestima, y puede conducir a diseños más seguros.

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