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Impact of natural and artificial ageing on the properties of multilayer external wall thermal insulation systems
Multilayer external wall thermal insulation systems are widely used in new constructions and for the retrofitting of building façades. Despite the increasing use as constructive solution, significant anomalies have been frequently identified on these systems only few years after their application, raising questions on their long-term durability. This paper focuses on the effects of one-year natural ageing and artificial ageing through hygrothermal cycles (heat/rain and heat/cold) on the water performance (capillary water absorption and drying kinetics), bio-susceptibility (mould development) and surface properties (colour, gloss, and roughness) of four multilayer external wall thermal insulation systems (three ETICS and a thermal rendering system). Results showed a significant loss of surface hydrophobicity after ageing. Considering the 24 h water absorption results, an increase up to 73% and 432% was obtained for the naturally and artificially aged systems, respectively, and when compared to the reference unaged systems. The drying kinetics was affected by ageing, with increases of the drying resistance ranging between 47% and 122% after artificial ageing. Traces of mould growth were observed on the artificially aged systems; however, no growth was detected on either the unaged or the one-year naturally aged systems. Substantial colour change for all systems after ageing was observed, confirming aesthetic alteration. Results contribute towards the development of implemented artificial ageing protocols, as well as for the delivery of multilayer thermal systems with enhanced performance and durability.
Year: 2022
Author(s): Parracha, J.; Borsoi, G.; Flores-Colen, I.; Veiga, M. R.; Lina Nunes
: Construction and Building Materials
Editor: Elsevier
Volume:
317.
Keywords: Natural ageing; Durability Artificial ageing; Durability; Thermal mortar; ETICS; Multilayer thermal system
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Impact of the Pressure Differences Between Road Galeries On Tunnels Generated by the Smoke Control System
Long motorway tunnels equipped with two independent unidirectional galleries are usually provided with longitudinal ventilation. This ventilation scheme, when applied to smoke control, can generate significant pressure differences between both roadway galleries, which may have an impact on the use of transverse galleries (escape routes). This paper present two-case studies where the results of measure- ments of these pressure differences taken in Mara ?o and Gardunha tunnels allowed the assessment of relevant flow parameters, as the pressure loss coefficient of the entrance portal, the friction factor in the tunnel and the coefficient of installation of the jet fans. The assessed parameters were used in the steady-flow energy equation for a streamtube to predict the impact of pressure differences on the protection of trans- verse galleries (emergency exits) in the case of fire. The results show that the pre- dicted pressure in the fire road gallery increases upstream the location of the fire and decreases downstream that location, when taking the pressure profile of the flow without fire as a reference. The models show that predicted pressure differences between the two road galleries in case of fire may be within the interval [200 Pa; - 100 Pa] in Mara ?o tunnel and [12 Pa; - 48 Pa] in Gardunha Tunnel, while the mea- surements in the no fire case show that they lay within the interval [29 Pa; - 50 Pa] in Mara ?o tunnel and [- 13 Pa; - 35 Pa] in Gardunha Tunnel
Year: 2022
Number Pages:
26p.
Author(s): Viegas, J.; Oliveira Costa, C.; Bernardo Monteiro; Pereira, P.
: Fire Technology 2022
Editor: Springer Science
Keywords: Pressure differences; Smoke control; Fire; Tunnels
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Impact Resistance of Rendering Mortars with Natural and Textile-Acrylic Waste Fibres
Renders should have an adequate resistance to impacts, since they must protect the substrate. The use of fibres may enhance the energy absorbed when the mortars are submitted to an impact load, which contributes to postpone the first crack, and control its propagation and width. In this study, the impact strength was measured by a falling mass from different heights. The cracking pattern and the impact energy for the appearance of the first crack and until failure were evaluated. An artificial accelerated ageing test was also performed, and the impact resistance was analysed before and after ageing. In order to analyse the effects of recycled fibres, wool, coir, flax and textile-acrylic waste fibres were used as reinforcement in cement and cement-lime mortars. The results indicated that the fibres
Year: 2022
Author(s): Pederneiras, C.; Veiga, M. R.; Brito, J.
: Fibers
Editor: MDPI
Volume:
2022.
Keywords: render; sustainability; recycled fibres; natural fibres; fibre-reinforced mortars; impact strength
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Impact Resistance of Rendering Mortars with Natural and Textile-AcrylicWaste Fibres
Renders should have an adequate resistance to impacts, since they must protect the substrate. The use of fibres may enhance the energy absorbed when the mortars are submitted to an impact load, which contributes to postpone the first crack, and control its propagation and width. In this study, the impact strength was measured by a falling mass from different heights. The cracking pattern and the impact energy for the appearance of the first crack and until failure were evaluated. An artificial accelerated ageing test was also performed, and the impact resistance was analysed before and after ageing. In order to analyse the effects of recycled fibres, wool, coir, flax and textile-acrylic waste fibres were used as reinforcement in cement and cement-lime mortars. The results indicated that the fibres
Year: 2022
Author(s): Pederneiras, C.; Veiga, M. R.; Brito, J.
: Fibers 2022
Editor: MDPI
Volume:
10.
Keywords: render; sustainability; recycled fibres; natural fibres; fibre-reinforcedmortars; Impact strength
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IMPLEMENTATION AND VALIDATION OF SAFEPORT SYSTEM AT SINES HARBOUR
SAFEPORT safety system aims to daily reports to Sines harbour administration, potencial emergency situations regarding ships operation in port areas caused by extreme weather-oceanographic conditions, that may occur in the next three. It consists of a set of numerical models and a qualitative risk assessment and forecasting. It uses forecasts provided offshore of the area under study of sea agitation, wind and tide. The characterization of the response of the free and moored ships at a berth is performed using the numerical modelswhich deals with formulations in the frequency and time domain. The system issue alerts, through danger levels associated with risk levels of exceedance of recommended values for movements and forces imposed on ship mooring systems. SAFEPORT can be adapted to any port. So far, it has been developed and adapted to three terminals of the port of Sines, where three different ships were simulated. This paper presents the developments made to date of the safety system, in terms of its implementation and validation. The numerical models run every day, in real-time mode, in a computer cluster and the system provide forecast results for the next 72 hours. The results are disseminated on a web page and a mobile application in a variety of formats.
Year: 2022
Author(s): Gomes, A.; Pinheiro, L.; Fortes, C. J. E. M.; Santos, J. A.
Editor: XXV ENMC, XIII ECTM
Keywords: Risk analysis; MOORNAV; Moored ships; Wave propagation; SWAMS; SAFEPORT
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Implementation of the swash model into HIDRALERTA system
Early warning systems are an important tool for local authorities to detect emergency situations in advance and initiate the necessary safety measure. The To-SEAlert project has the aim of increasing the efficiency, robustness and reliability of the HIDRALERTA coastal hazards early warning system. This study shows a first intent to implement the SWASH numerical model to simulate wave overtopping for the Ericeira prototype. SWASH was implemented for one breakwater profile where overtopping discharge and associated risk levelsare estimated. It was compared to the current approach used in HIDRALERTA, the neuronal network NN_OVERTOPPING2. Finally, both approaches were compared with previously analysed video images of the site. The results showed that SWASH generally overestimates overtopping and is not in good agreement with the NN_OVERTOPPING2 or the video images. A possible reason might be the wave direction, which cannot be included in one-dimensional simulations in SWASH.
Year: 2022
Author(s): Manz, A.; Zózimo, A. C.; Fortes, C. J. E. M.; Pinheiro, L.
Editor: XXV ENMC, XIII ECTM, 9º MCSul e IX SEMENGO
Keywords: SWASH model; Risk Reductio; Wave Overtopping; Early Warning System
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Improved assessment of maximum streamflow risk management of Hydraulic structures. A case study
Understanding the risks associated with the likelihood of extreme events and their respective consequences for the stability of hydraulic infrastructures is essential for flood forecasting and engineering design purposes. Accordingly, a hydrological methodology for providing reliable estimates of extreme discharge flows approaching hydraulic infrastructures was developed. It is composed of a preliminary assessment of missing data, quality and reliability for statistically assessing the frequency of flood flows, allied to parametric and non-parametric methods. Model and parameter uncertainties are accounted for by the introduced and proposed modified model averaging (modified MM) approach in the extreme hydrological event's prediction. An assessment of the parametric methods accuracy was performed by using the non-parametric Kernel Density Estimate (KDE) as a benchmark model. For demonstration and validity purposes, this methodology was applied to estimate the design floods approaching the case study
Year: 2022
Number Pages:
11p.
Author(s): Bento, A. M.; Gomes, A.; Pêgo, J. P.; Viseu, T.; Couto, L. T.
: International Journal of River Basin Management
Editor: Taylor & Francis
Keywords: modified MM; KDE; hydraulic infrastructures; Flood events
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Inference of dynamic origin-destination matrices with trip and transfer status from individual smart card data
The provision of seamless public transport supply requires a complete understanding of the real traffic dynamics, comprising origin-to-destination multimodal mobility patterns along the transport network. However, most current solutions are centred on the volumetric analysis of passengers
Year: 2022
Number Pages:
18p.
Author(s): Cerqueira, S.; Arsénio, E.; Henriques, R.
: European Transport Research Review
Editor: Springer
Volume:
14.
Keywords: Origin-destination matrices; Sustainable mobility; Big data; Data science; Multimodality; Public transport
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Influence of Exposure Conditions and Particulate Deposition on Anodized Aluminum Corrosion
Anodizing is commonly used for corrosion protection of aluminum and its alloys in the construction industry. The anodic aluminum oxide (AAO) coating has a high ability to prevent the development of extensive pitting corrosion in aluminum substrates, particularly in marine sites, as was observed during a 10-year atmospheric corrosion study carried out in several marine and industrial sites. However, this study also evidenced that this coating can be highly affected by the deposition of particulate material in industrial polluted environments, sometimes in unexpected ways. This study presents information on the atmospheric corrosion of anodized aluminum exposed at two different chemical industrial complexes: a fertilizer production plant and a pulp and paper mill. Visual assessment of surface changes, pitting depth and mass variation with exposure were determined to quantify the degradation suffered. Additionally, SEM/EDS analyses were carried out on the exposed surfaces. Based on the results obtained, the role played by the deposition of airborne particles present in the two environments with respect to the type and level of damage observed is discussed. Deposits of roasted pyrite ash and phosphates or of wood chips and lime particles enhanced pitting corrosion or caused dissolution of the AAO coating.
Year: 2022
Number Pages:
770-786pp..
Author(s): Pereira, E. V.; Fontinha, I. R.
: Corros. Mater. Degrad.
Editor: MDPI
Volume:
2022 3(4).
Keywords: anodized aluminum; atmospheric corrosion tests
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Injection of discontinuities in concrete dams with cement-based grouts
Injecting discontinuities is a recurrent procedure for the rehabilitation of concrete hydraulicstructures, namely repairing cracked dam bodies and deteriorated lift and contraction joints.Within this scope, a relatively detailed description of the most important cement injectiongrouts features is presented, including the main advantages and drawbacks compared toalternatives. The cement-based grouts are among the most utilised materials in these contexts.Economic and environmental related aspects are among the main advantages ofcement-based grouts, although some technical features of these grouting materials are alsofavourable. The equipment utilised for the preparation and for the application of cementitiousgrouts is also mentioned. This document also addresses aspects related to the assessment ofconcrete dams
Year: 2022
Number Pages:
252-264pp..
Author(s): Conde Silva, J.; Serra, C.
: Journal of Structural Integrity and Maintenance
Editor: Taylor & Francis
Volume:
VOL. 7, NO. 4.
Keywords: Grouting; Cement; Rehabilitation; Maintenance; Hydraulic structures
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