45 research outputs found

    Brita Lavada – An eco-efficient decorative mortar from Madeira Island

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    Brita lavada (washed gravel, in direct translation) is a decorative coating technology with a mortar based on cement, local Madeira basalt gravel and black pigment, currently used for masonry rendering on 20th-21st century Madeiran built heritage simulating stone masonry or cladding. Comparison of Brita Lavada and other cement based coating mortars was made regarding physical behaviour. The Brita Lavada shows high mechanical strength, acceptable water absorption and good water vapour permeability, what can justify its good durability on site and continuous application. The previous justify the interest on preserving the technology and is an example of optimised used of a local material, in the case a very hard basalt, with no possibility to be used for stonework, as a specific resource for a traditional, durable, eco-efficient decorative coating

    Pulse velocity assessment of early age creep of concrete

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    Creep of concrete can have damaging effects by inducing deformations that may contribute or eventually lead to cracks, which influence concrete durability, steel reinforcement exposure to corrosion, and aesthetic damage to architectural buildings. This research investigated the early age creep deformation in concrete samples made with normal, lightweight (Lytag), recycled concrete, and recycled asphalt aggregates using ultrasonic pulse velocity measurements. Creep was achieved by applying a load corresponding to 30% of the strength of concrete to 100 Ă— 250 mm prisms. The compressive load was applied from 24 h after mixing and up to 27 days. The results and analysis of measurements obtained for stress development, specific creep (creep strain per unit stress), and ultrasonic pulse velocity measured up to 27 days after load application are presented. Empirical models that allow the assessment of creep of concrete using ultrasonic pulse velocity measurements are also presented. Early age specific creep is higher for recycled asphalt aggregate than Lytag aggregate and recycled concrete aggregate concretes, which are higher than gravel concrete. Measurements of ultrasonic pulse velocity could be used to determine creep but further work to refine this technique is required
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