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Atrazine (1), Atraton (2) and Ametryn (3) are photodegraded upon 254 nm irradiation, yielding 2-OH-atrazine (4) as a photoproduct. Dealkylation products are also generated, and 4-ethylamino-6-isopropylamino-(1,3,5)-triazine was also found as a photoproduct of 3. The main photoreaction is proposed to be an addition-elimination, yielding 4, which subsequently photodegrades. The ease of photodegradation depends on the electron availability at position C-2, the observed order of photoreactivity being 1 > 3 > 4 > 2. Copyright © 2003 John Wiley & Sons, Ltd.

In the last years, significant research in the context of bond of near-surface mounted (NSM) fibre reinforced polymer (FRP) systems in concrete has been conducted at the Department of Civil Engineering of the University of Minho. This paper presents a brief summary of the major results obtained in that research, namely in terms of durability, quality control and design topics. Accelerated ageing tests on NSM FRP bond specimens were conducted to simulate different environmental conditions. A new method was developed and applied to investigate the evolution of the adhesive stiffness and the bond behaviour of NSM systems for different curing conditions used for quality control of FRP installations. Regarding the bond design, two existing guidelines’ formulas were adapted to the partial safety factors framework., This work was supported by FEDER funds through the Operational Program for Competitiveness Factors – COMPETE and National Funds through FCT (Portuguese Foundation for Science and Technology) under the projects CutInDur FCOMP-01-0124-FEDER-014811 (FCT PTDC/ECM/112396/2009), FRPreDur FCOMP-01- 0124-FEDER-028865 (FCT PTDC/ECM-EST/2424/2012), FRPLongDur POCI-01-0145-FEDER-016900 (FCT PTDC/ECM-EST/1282/2014) and partly financed by the project POCI-01-0145-FEDER-007633. The following individual grants are also acknowledged: SFRH/BD/80338/2011 (P. Fernandes), SFRH/BD/87443/2012 (M. Coelho), SFRH/BD/89768/2012 (P. Silva) and SFRH/BD/80682/2011 (J. Granja).

The constant changes in the world market demand flexible and fluid organizational structures, such as rotating and engaging human effort, to provide high performance. Therefore, organizations make use of distributed multicultural teams, meetings, and online lead projects. However, these social categorization processes can become a disadvantage if trigger potential conflicts during task performance. Distributed teams can also be difficult to manage, and their members can face extra adversities in communication. Architecture, Engineering and Construction Industry (AEC), is a context where the use of distributed teams is growing significantly, particularly through the enabling features of Building Information Modelling (BIM) methodologies. This paper was aimed at the diagnosis of communication behaviour in distributed teams in the context of a PBL methodology that requested students to work in distributed teams on two distinct locations. For that, the authors managed a workshop on Lean Project Management and Collaborative Tools in the European Master in Building Information Modelling (BIM A+) using a Lego for Scrum activity, adapted to a team of students distributed in Portugal and Slovenia. After that, nine distributed teams of students had to design exposition pavilions in BIM platform and using collaborative tools. At the end, each team had to present the project for the entire body of students and faculty, located in Guimaraes (Portugal) and Ljubljana (Slovenia)., (undefined)

When large quantities of data are acquired in long-term monitoring works, the use of automatic modal identification procedures is mandatory for the feasibility of real-time data interpretation, damage detection, model updating, or others. This paper presents an innovative algorithm for real-time remote processing the information recorded by ambient vibration tests. This algorithm aims at generating and interpreting the stabilization diagrams resultant from the application of parametric methods (such as the Stochastic Subspace Identification – SSI) to the collected time domain data. The proposed algorithm was validated in two stages: (i) considering numerical examples with artificially generated data and (ii) in a field test for tracking the stiffening process of concrete since early ages. The results of these two rounds of validation tests evidenced the high accuracy of the automatic estimations of this new algorithm and thus, the feasibility for its incorporation as a tool in future Structural Health Monitoring works., (undefined)

The present paper aims to contribute to the knowledge of the long-term performance and durability of concrete structures strengthened with the Near-Surface Mounted (NSM) technique. The durability of strengthening systems is affected by environmental conditions, such as freeze-thaw and temperature cycling, exposure to aggressive chemical agents and ultraviolet light. Additionally, the long-term performance of the NSM system could be compromised by fatigue loading, which may result in deterioration and weakening of individual components (steel, FRP, concrete), or loss of bond performance and composite action. Thus, in order to assess the bond and flexural behavior of NSM CFRP strengthening system under fatigue loading, an experimental program was carried out, composing of direct pullout tests and loading of slab specimens. The main investigated parameters were the stress level (or fatigue stress) and the amplitude of cycle. This paper describes the conducted tests and presents and analysis the obtained results., Fundação para a Ciência e a Tecnologia (FCT)

The performance of NSM systems directly depends on the performance of the adhesive which can only be reached if a proper curing conditions and time are assured. In order to assess the curing process of the adhesives, as well as the corresponding bond behavior, adequate non-destructive testing approaches are required. Nonetheless, scarce information could be found in the literature in concern to this relevant topic. To fill such gap, the present paper proposes a new method for continuous quality control of epoxy adhesives, based on adaptations of an existing technique originally devised for continuous monitoring of concrete E-modulus since casting, called EMM-ARM (Elasticity Modulus Monitoring through Ambient Response Method). This work reports the simultaneous study of the adhesive through EMM-ARM, together with direct pullout tests at several ages on concrete specimens strengthened with NSM CFRP laminate strips using the same epoxy. The tests are described, and the obtained results are presented and discussed, highlighting the potential of applying EMM-ARM for quality control and decision-making assistance of NSM systems., FCT -Fuel Cycle Technologies(undefined)

A new methodology that allows the continuous measurement of concrete E- modulus since casting is presented in this paper. This methodology is a variant to the classical resonant frequency methods, which have the downside of requiring concrete to be de-mouldable and withstand mechanical impact to start testing. The proposed experimental setup comprises a simply supported beam made-up with an acrylic tube, filled with the concrete to be tested, whose mid-span vertical accelerations induced just by ambient vibrations are continuously monitored by an accelerometer. The numerical treatment of the monitored accelerations allows identification of the 1st resonant frequency of the composite beam, which is evolving as concrete hardens. The E-modulus of concrete can thus be directly obtained from the monitored frequency. Besides the description of the overall setup, the results obtained in an experiment in which the concrete E-modulus was quantified also through static tests on the beam and via compressive tests in cylinders are presented and discussed. (c) 2010 Taylor & Francis Group, London.

Insulated sandwich wall panels are frequently composed of external concrete layers, mechanically connected through metallic connectors, such as trusses. Due to their high thermal conductivity, these connectors generally cause thermal bridges on the building envelope. In view of this problem, an innovative system is proposed where FRP connectors are used together with a thermal insulation layer. Steel Fibre Reinforced Self-Compacting Concrete (SFRSCC) wythes are also used to obtain panels that are both technically and economically advantageous. However, to present day there is no experimental data on the mechanical behaviour of the suggested connections. In this research, an experimental study is performed to characterize different types of FRP-SFRSCC connections under pull-out tests. Shear connection behaviour under monotonic loading is evaluated with slip controlled tests. Embedded and adhesively bonded connection solutions between SFRSCC layers and FRP connectors are studied., (undefined)

The present work intends to contribute for the knowledge on durability performance of the near-surface mounted (NSM) strengthening technique, which is an issue that still requires significant research effort. For that purpose, an experimental program was developed using cubic pullout and slab specimens strengthened with NSM carbon fiber reinforced polymer (CFRP) strips. These specimens were submitted to thermal cycles in order to study the effect of this environmental action on the effectiveness of the NSM technique. The thermal cycles were defined according to the EN 13687-3 standard. After being submitted to this action during up to eight months, the specimens were monotonically tested up to failure using four-point bending and pullout direct test configurations for slabs and cubic specimens, respectively. To compare the performance of these specimens with non-aging ones, control specimens were also tested. The obtained results indicate that the loading capacity of the slabs and damage mechanism were not affected by thermal cycles. Nevertheless, the bond strength increased with the number of thermal cycles. Therefore, these results suggest that the concrete elements strengthened with CFRP NSM technique are not susceptible to temperature in a range of -15°C to 60°C., FCT -Federación Española de Enfermedades Raras

With the increasing awareness of global warming, largely due to the emission of large amounts of CO2, some attempts have been made to develop strate-gies to help combat the growing trend of global warming. To reduce the harmful effects of concrete production, efforts are being made to reduce the amount of cement used by replacing the cement with mineral additives to maintain or improve the properties of the concrete. In addition, the use of waste materials as substitutes for cement and other concrete constituents is being promoted and investigated. This paper presents an experimental study on the influence of ash from wood biomass (used as a cement substitute up to 30%) and the addition of recycled polymer fibers from waste rubber in an amount of 2 kg/m2 (used as a substitute for industrial polypropylene fibers) on the residual mechanical and durability properties of concrete exposed to high temperatures up to 600°C. In addition, reference concretes were prepared using only cement and industrial polypropylene fibers for the comparison purposes. A total of 5 different mixes were tested. The following tests were performed on the con-crete specimens before and after thermal treatment: compressive strength, static modulus of elasticity, ultrasonic pulse velocity and gas permeability. These properties represent the input parameters for the evaluation of the condition of reinforced concrete elements after exposure to fire. The ob-tained results show that the use of the investigated waste materials in con-crete leads to comparable or slightly better properties after fire exposure compared to the reference concrete.