24 resultados para Cement.


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Dissertação para obtenção do Grau de Mestre em Engenharia Civil, Perfil de Estruturas

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Construction and Building Materials 49 (2013), 315-327

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Equity research report

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Earthen building materials bear interesting environmental advantages and are the most appropriate to conserve historical earth constructions. To improve mechanical properties, these materials are often stabilized with cement or lime, but the impact of the stabilizers on the water transport properties, which are also critical, has been very rarely evaluated. We have tested four earth-based repair mortars applied on three distinct and representative rammed earth surfaces. Three mortars are based on earth collected from rammed earth buildings in south of Portugal and the fourth mortar is based on a commercial clayish earth. The main objective of the work was over the commercial earth mortar, applied stabilized and not stabilized on the three rammed earth surfaces to repair, to assess the influence of the stabilizers. The other three earth mortars (not stabilized) were applied on each type of rammed earth, representing the repair only made with local materials. The four unstabilized earth materials depicted nonlinear dependence on t1/2 during capillary suction. This behaviour was probably due to clay swelling. Stabilization with any of the four tested binders enabled the linear dependence of t1/2 expected from Washburn's equation, probably because the swelling did not take place in this case. However, the stabilizers also increased significantly the capillary suction and the capillary porosity of the materials. This means that, in addition to increasing the carbon footprint, stabilizers like cement and lime have functional disadvantages that discourage its use in repair mortars for raw earth construction.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Renders are an important item in historical buildings and the need for their periodical re-application is a basic conservation procedure. In modern times there has been a trend towards the replacement of traditional pure lime mortars by new formulations including Portland cement or hydraulic lime. Apart from those interventions on specific and very important monuments, in which the use oftraditional non-hydraulic mortars can be enforced, in most of the projects involving less than first order magnitude heritage the use of some sort of hydraulic components is becoming the rule rather than the exception. The present paper describes and analyses the results of an experimental study with ten formulations of current mortars - including some that can hardly be considered as adequate conservation procedures - allowing a direct comparison in terms of some of the most relevant characteristics.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia do Ambiente, Perfil Gestão e Sistemas Ambientais

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The studied materials were sampled from several conglomerate and carbonate sandstone units, overlapped for 23 meters. This formation represents a debris flow dominated alluvial fan alternating with quiet sedimentary conditions. These deposits of probably Paleogene age were placed upon mafic and ultramafic rocks that are the exclusive source of sediments. Optical and SEM identification, microanalysis and XRD studies (with decomposition procedures) of clay fractions obtained after high-speed centrifugation were performed in order to characterise the clay minerals content. The results of the analytical program allowed the establishment of the following remarks: a) Fe-rich montmorillonite dominance over paligorskite, chlorite, chlorite-smectite mixed-layers, serpentine and talc; b) smectites in the 12.4 - 15 A range, expanding to about 17 A after EG treatment; c) serpentine and talc as secondary minerals in the interior of altered clasts; d) chlorite and clorite smectite mixed-layer compositions in the borders of the clasts and in the cement. The composition of sediments results from coarse clasts eroded from mafic and ultramafic rocks and clayey material. Clasts show evidences of post-depositional weathering (coatings of chlorite and smectite). Clayey material has the contributions of i) inherired chlorite, smectite and chlorite-smectite mixed-layers; ii ) authigenic crystallisation of Fe-montmorillonite (due to availability of Fe in the crystallising solutions following previous weathering events); iii) authigenic paligorskite associated to a carbonate cement.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Environmental Training in Engineering Education (ENTREE 2001) - integrated green policies: progress for progress, p. 329-339 (Florence, 14-17 November 2001; proceedings published as book)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Proceedingsof the XII DBMC – 12th International Conference on Durability of Building Materials and Components, Vol.2, Porto, FEUP, March 2011, p.689-696

Relevância:

10.00% 10.00%

Publicador:

Resumo:

3rd Historic Mortars Conference, 11-14 September 2013, Glasgow, Scotland

Relevância:

10.00% 10.00%

Publicador:

Resumo:

RESTAPIA 2012 - Int. Conf. on Rammed Earth Conservation, Valencia, 21-23 June 2012

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Cement & Concrete Composites 45 (2014) 264–271

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Materials Science Forum Vols. 730-732 (2013) pp 617-622

Relevância:

10.00% 10.00%

Publicador:

Resumo:

HMC08 - 1st Historical Mortars Conference: Characterization, Diagnosis, Conservation, Repair and Compatibilit, LNEC, Lisbon, 24-26 September 2008

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Thesis submitted to obtain the Doctoral degree in Energy and Bioenergy