184 resultados para compressive well


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This paper presents experimental tests carried out on steel fibre reinforced concrete samples, including mechanical tests as well as non-destructive technique (electrical resistivity) and non destructive technique on cores (X-ray). Electrical resistivity measurements are done as a blind test, to characterise the electrical anisotropy and deduce the distribution and the orientation of fibres. These results are compared to X-ray imaging to check the quality of the non destructive evaluation. Then, flexural and compressive strength are measured on specimens to assess the influence of fibre distribution on the concrete properties.

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The prisoner provisions under the Northern Ireland Peace Agreement clearly emphasised the importance of the reintegration and civic inclusion of ‘politically motivated’ former prisoners; however, numerous barriers to full reintegration remain. Even though these prisoners were released as part of a peace process, based on principles of conflict transformation and reconciliation, there were still The prisoner provisions under the Northern Ireland Peace Agreement emphasised the importance of the reintegration and civic inclusion of ‘politically motivated’ former prisoners; however, numerous barriers to full reintegration remain. Notwithstanding the fact that these prisoners were released as part of a peace process, based on principles of conflict transformation and reconciliation, there were still numerous conditions placed upon them as part of their release process and they continued to hold a ‘criminal’ record upon release. As with ‘ordinary’ ex-prisoners, these ‘politically motivated’ former prisoners have subsequently faced numerous obstacles in their attempts to reintegrate back into society, particularly in the area of employment. Recognising that they needed to deal with the consequences of imprisonment, ‘politically motivated’ former prisoners formed numerous self-help organisations to assist in the reintegration process and have mobilised to lobby for protection against the discrimination and unequal treatment experienced by ex-prisoners seeking employment. This article explores the remaining barriers to employment for ‘politically motivated’ former prisoners and the consequences of these barriers. The article moves to assess how prisoner groups have subsequently used a ‘rights based’ discourse to engage local government in their struggle to overcome existing obstacles before finally concluding that any piecemeal attempt to remove barriers to full reintegration will only impede the longer term conflict transformation process in Northern Ireland.

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A study undertaken at the University of Liverpool has investigated the potential for using construction and demolition waste (C&DW) derived aggregate in the manufacture of a range of precast concrete products, i.e. building and paving blocks and pavement flags. Phase III, which is reported here, investigated
concrete pavement flags. This was subsequent to studies on building and paving blocks. Recycled demolition aggregate can be used to replace newly quarried limestone aggregate, usually used in coarse (6 mm) and fine (4 mm-to-dust) gradings. The first objective was, as was the case with concrete building
and paving blocks, to replicate the process used by industry in fabricating concrete pavement flags in the laboratory. The ‘‘wet’’ casting technique used by industry for making concrete flags requires a very workable mix so that the concrete flows into the mould before it is compressed. Compression squeezes out water from the top as well as the bottom of the mould. This industrial casting procedure was successfully replicated in the laboratory by using an appropriately modified cube crushing machine and a special mould typical of what is used by industry. The mould could be filled outside of the cube crushing machine and then rolled onto a steel frame and into the machine for it to be compressed. The texture and mechanical properties of the laboratory concrete flags were found to be similar to the factory ones. The experimental work involved two main series of tests, i.e. concrete flags made with concrete- and
masonry-derived aggregate. Investigation of flexural strength was required for concrete paving flags. This is different from building blocks and paving blocks which required compressive and tensile splitting strength respectively. Upper levels of replacement with recycled demolition aggregate were determined
that produced similar flexural strength to paving flags made with newly quarried aggregates, without requiring an increase in the cement content. With up to 60% of the coarse or 40% of the fine fractions replaced with concrete-derived aggregates, the target mean flexural strength of 5.0 N/mm2 was still
achieved at the age of 28 days. There was similar detrimental effect by incorporating the fine masonry-derived aggregate. A replacement level of 70% for coarse was found to be satisfactory and also conservative. However, the fine fraction replacement could only be up to 30% and even reduced to 15% when used for mixes where 60% of the coarse fraction was also masonry-derived aggregate.

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To test the hypothesis that more disadvantaged patients are perceived by general practitioners (GPs) as being less attractive than their more affluent peers.