scholarly journals Corrosion Assessment of a Weathering Steel Bridge Structure after 30 Years of Service

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3788
Author(s):  
Agnieszka Królikowska ◽  
Leszek Komorowski ◽  
Izabela Kunce ◽  
Damian Wojda ◽  
Katarzyna Zacharuk ◽  
...  
Keyword(s):  
Phase Analysis ◽  
Diffraction Method ◽  
Visual Assessment ◽  
Product Layer ◽  
Carbon Steels ◽  
Bridge Engineering ◽  
Quantitative Phase Analysis ◽  
Weathering Steel ◽  
Steel Bridge ◽  
Structural Problems

The first steel with improved resistance towards atmospheric corrosion, the so-called weathering steel, was patented in the USA in 1933 and was initially used for coal railway cars, and after that, in building and bridge engineering. Weathering steels show higher corrosion resistance than carbon steels in many types of atmosphere due to their ability to form a compact, stable, adherent and protective patina during the time of exposure. Morphological evaluation of the appearance of the corrosion product layer, together with phase analysis of its components, can enable determination of the type of patina and the degree of protection of the steel. To support the visual assessment of a patina, a check based on the qualitative and quantitative phase analysis of its components may be carried out, and the PAI (Protective Ability Index) can be calculated. The estimation of the corrosion processes on original Polish-made weathering steel (12HNNbA) was carried out on a 30-year-old bridge in Poland. There are some structural problems within the deck derived not only from corrosion but also steel cracking, both inside and outside the boxes, at different heights. Fourteen representative samples of patina were analysed and their phase structures were determined by the X-ray powder diffraction method. The PAIs were determined and analysed.

Impact of Rutile Fraction on TiO2 Visible-Light Absorption and Visible-Light-Induced Photocatalytic Activity

2018 ◽  
Author(s):  
David Maria Tobaldi ◽  
Luc Lajaunie ◽  
ana caetano ◽  
nejc rozman ◽  
Maria Paula Seabra ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Light Absorption ◽  
Solid Phase ◽  
Diffraction Method ◽  
Band Alignment ◽  
Quantitative Phase Analysis ◽  
Transmission Microscopy ◽  
Visible Light Absorption ◽  
X Ray

<div>Titanium dioxide is by far the most utilised semiconductor material for photocatalytic applications. Still, it is transparent to visible-light. Recently, it has been proved that a type-II band alignment for the rutile−anatase mixture would improve its visible-light absorption.</div><div>In this research paper we thoroughly characterised the real crystalline and amorphous phases of synthesised titanias – thermally treated at different temperatures to get distinct ratios of anatase-rutile-amorphous fraction – as well as that of three commercially available photocatalytic nano-TiO2. </div><div>The structural characterisation was done via advanced X-ray diffraction method, namely the Rietveld-RIR method, to attain a full quantitative phase analysis of the specimens. The microstructure was also investigated via an advanced X-ray method, the whole powder pattern modelling. These methods were validated combining advanced aberration-corrected scanning transmission microscopy and high-resolution electron energy-loss spectroscopy. The photocatalytic activity was assessed in the liquid- and gas-solid phase (employing rhodamine B and 4-chlorophenol, and isopropanol, respectively, as the organic substances to degrade) using a light source irradiating exclusively in the visible-range.</div><div>Optical spectroscopy showed that even a small fraction of rutile (2 wt%) is able to shift to lower energies the apparent optical band gap of an anatase-rutile mixed phase. But is this enough to attain a real photocatalytic activity promoted by merely visible-light?</div><div>We tried to give a reply to that question.</div><div>Photocatalytic activity results in the liquid-solid phase showed that a high surface hydroxylation led to specimen with superior visible light-induced catalytic activity (i.e. dye and ligand-to-metal charge transfer complexes sensitisation effects). That is: not photocatalysis <i>sensu-strictu</i>.</div><div>On the other hand, the gas-solid phase results showed that a higher amount of the rutile fraction (around 10 wt%), together with less recombination of the charge carriers, were more effective for an actual photocatalytic oxidation of isopropanol.</div>

scholarly journals Review of annual progress of bridge engineering in 2019

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Renda Zhao ◽  
Yuan Yuan ◽  
Xing Wei ◽  
Ruili Shen ◽  
Kaifeng Zheng ◽  
...  
Keyword(s):  
High Performance ◽  
Concrete Bridges ◽  
Bridge Engineering ◽  
Research Progress ◽  
Steel Bridge ◽  
Wind Resistance ◽  
Main Research ◽  
Bridge Model ◽  
Bridge Evaluation ◽  
Bridge Structures

AbstractBridge construction is one of the cores of traffic infrastructure construction. To better develop relevant bridge science, this paper introduces the main research progress in China and abroad in 2019 from 13 aspects, including concrete bridges and the high-performance materials, the latest research on steel-concrete composite girders, advances in box girder and cable-supported bridge analysis theories, advance in steel bridges, the theory of bridge evaluation and reinforcement, bridge model tests and new testing techniques, steel bridge fatigue, wind resistance of bridges, vehicle-bridge interactions, progress in seismic design of bridges, bridge hydrodynamics, bridge informatization and intelligent bridge and prefabricated concrete bridge structures.

scholarly journals Challenges of Mechanochemistry: Is In Situ Real-Time Quantitative Phase Analysis Always Reliable? A Case Study of Organic Salt Formation

2017 ◽  
Vol 4 (9) ◽  
pp. 1700132 ◽  
Author(s):  
Adam A. L. Michalchuk ◽  
Ivan A. Tumanov ◽  
Sumit Konar ◽  
Simon A. J. Kimber ◽  
Colin R. Pulham ◽  
...  
Keyword(s):  
Real Time ◽  
Phase Analysis ◽  
Organic Salt ◽  
Quantitative Phase Analysis ◽  
Salt Formation ◽  
Quantitative Phase

Design Challenges of the Horotiu Paa Bridge - Maximising Structural Efficiency and Economy

2016 ◽  
Author(s):  
Liam Edwards
Keyword(s):  
New Zealand ◽  
Weathering Steel ◽  
Steel Bridge ◽  
Design Development ◽  
Economic Prosperity ◽  
Total Length ◽  
The Government ◽  
National Significance ◽  
Bridge Spans ◽  
Design Challenges

The Horotiu Paa Bridge, also known as the Karapiro Gully Bridge is the largest weathering steel bridge in New Zealand. Construction of the bridge was recently completed in November 2015. The bridge is part of the Cambridge section of the Waikato Expressway in New Zealand. The Waikato Expressway is one of the seven state highways, named the Roads of National Significance, identified by the government as essential to New Zealand's economic prosperity. The bridge spans over the Karapiro Gully with a total length of 200m, consisting of four 50m long equal spans and is 24m wide, servicing 4 lanes of traffic.<p> This paper discusses the design development, key design aspects, innovations and technical challenges for the design of the Horotiu Paa Bridge.

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