498 research outputs found

    Rheology of fresh cement and concrete

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    Rheological properties of mortars prepared with different sands

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    YesThe principal aim of this paper is to investigate the effect of sand grading, surface morphology, and content on the rheological properties—that is, yield stress and plastic viscosity—of fresh mortar. Mortars were produced from four different types of sand at two volumetric cement-sand ratios of 1/0.9 and 1/0.6. Each blend was prepared with five water-cement ratios of 0.60, 0.55, 0.50, 0.45, and 0.40. The rheometer was used to determine yield stress and plastic viscosity parameters of each cement paste and mortar. Test results show that the relative yield stress and plastic viscosity of mortar to cement paste is inversely proportional to the excess paste thickness up to low values, below which the surface texture of sand particles becomes significant

    Rheology of fresh mortar

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    Resumen: Los materiales basados en cementos presentan una enorme importancia tecnológica. Para una correcta utilización es necesario que sea posible su transporte y conformado en un estado “fresco”, por lo que es fundamental controlar su comportamiento reológico. En esta conferencia se describe el comportamiento reológico de morteros y productos relacionados, en situaciones prácticas, donde se tratarán casos concretos, y se discutirán las principales características de cada comportamiento. Además, se presentarán los nexos de unión entre la reología y la tecnología de los materiales de la construcción. Abstract: Cement-based materials are of enormous technological importance and their satisfactory performance depends on being able to transport and mould them in the freshly mixed state. This conference describes the rheology of mortars and related products in the context of practical situations, and deals with testing and measurement, together with the main features of their behaviour. It explores the links between rheology and technology.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Life-cycle assessment of buildings: a Review

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    Life-Cycle Assessment (LCA) is one of various management tools for evaluating environmental concerns. This paper reviews LCA from a buildings perspective. It highlights the need for its use within the building sector, and the importance of LCA as a decision making support tool. It discusses LCA methodologies and applications within the building sector, reviewing some of the life-cycle studies applied to buildings or building materials and component combinations within the last fifteen years in Europe and the United States. It highlights the problems of a lack of an internationally comparable and agreed data inventory and assessment methodology which hinder the application of LCA within the building industry. It identifies key areas for future research as (i) the whole process of construction, (ii) the relative weighting of different environmental impacts and (iii) applications in developing countries

    Hygrothermal properties of NHL mortars

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    Hygrothermal simulation software enables designers to assess the impact of insulation retrofits on solid walls before a retrofit project starts and help to avoid the negative effects on solid wall performance. However, the material databases used by the software lack information on the material properties of the traditional masonry used in Scotland. The hygrothermal properties of uncarbonated and carbonated lime mortar made with St Astier NHL2, NHL3.5 and NHL5 and Loanleven sand have been determined by laboratory testing. Thermal conductivity, sorptivity or water absorption coefficient by partial immersion, water vapour permeability (dry and wet cup), hygroscopic sorption, density and porosity results are presented
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