An old bridge transformed into a new one: possible, recommendable?

2019 ◽  
Author(s):  
Diego Carro-López ◽  
Ignasi Fernandez ◽  
Natalie Williams Portal
Keyword(s):  
Environmental Issues ◽  
Quality Standards ◽  
Structural Effect ◽  
Coarse Fraction ◽  
Concrete Bridges ◽  
Recycled Aggregates ◽  
Structural Elements ◽  
The Past ◽  
Reinforced Concrete Bridges ◽  
Natural Aggregates

<p>There is an extensive network of reinforced concrete bridges that give service to roads, highways and railways. These structures where constructed with quality standards of the past, and they suffer of severe problems. Now we consider the idea of substituting them with structural elements with much longer service life. However, there is an important question to be addressed in this area: what to do with the existing infrastructure that would be demolished. Even more if we consider environmental issues.</p><p>One good example of this recurrent problem could be found in the case of the Gullspång bridge (Sweden). It was constructed in 1935 and it was severely damaged with corrosion. The administration decided in the 2016 that no further repair would be done and that the bridge would be demolished and a new erected in substitution. A fraction of the concrete from the old bridge was crushed and processed to produce new aggregate. With this aggregate, using the coarse fraction, it was analyzed the structural effect of replacing natural aggregates with these recycled aggregates. The performance of the new structural elements was positive, and it seems that a high percentage of the natural aggregates could be replaced with recycled ones.</p>

scholarly journals On the Possibility of Using Recycled Mixed Aggregates and GICC Thermal Plant Wastes in Non-Structural Concrete Elements

2019 ◽  
Vol 11 (3) ◽  
pp. 633 ◽  
Author(s):  
Carlos Rodríguez ◽  
Isidro Sánchez ◽  
Isabel Miñano ◽  
Francisco Benito ◽  
Marta Cabeza ◽  
...  
Keyword(s):  
Fly Ash ◽  
Coarse Fraction ◽  
Production Costs ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Chloride Ingress ◽  
Structural Concrete ◽  
Construction And Demolition Wastes ◽  
Concrete Production ◽  
Natural Aggregates

Industrial wastes are often used as aggregate in concrete production to promote a more sustainable construction and to reduce production costs. This article presents the results of an experimental campaign on the influence of replacing natural aggregate with several construction and demolition wastes (C&DW) as recycled aggregate, as well as the use of fly ash and slag, wastes produced in Gas Incinerator Combined Cycle (GICC) thermal power plants, in the mix design of non-structural concrete. Different percentages of natural aggregates were substituted with recycled aggregates either coming from construction and demolition wastes, or from the coarse fraction of the slags from thermic plants in the manufacture of concrete. The mechanical properties, capillary water absorption, density, carbonation, chloride ingress and sulphate resistance have been tested. The results show a decrease in properties when C&DW are used. Fine fraction of slag and fly ash has an important advantage, and can even improve the long term properties of concrete prepared with natural aggregates. Coarse fraction of slag as a recycled aggregate generally improves most of the properties of manufactured concretes.

Ionic Liquids for the Synthesis of Five-Membered N,N-, N,N,N- and N,N,N,NHeterocycles

2019 ◽  
Vol 23 (11) ◽  
pp. 1214-1238 ◽  
Author(s):  
Navjeet Kaur ◽  
Pranshu Bhardwaj ◽  
Meenu Devi ◽  
Yamini Verma ◽  
Neha Ahlawat ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Organic Synthesis ◽  
Heterocyclic Compounds ◽  
Reaction Medium ◽  
Environmental Issues ◽  
Organic Reaction ◽  
Environment Friendly ◽  
The Past ◽  
Area Of Interest ◽  
Major Subject

Due to special properties of ILs (Ionic Liquids) like their wide liquid range, good solvating ability, negligible vapour pressure, non-inflammability, environment friendly medium, high thermal stability, easy recycling and rate promoters etc. they are used in organic synthesis. The investigation for the replacement of organic solvents in organic synthesis is a growing area of interest due to increasing environmental issues. Therefore, ionic liquids have attracted the attention of chemists and act as a catalyst and reaction medium in organic reaction with high activity. There is no doubt that ionic liquids have become a major subject of study for modern chemistry. In comparison to traditional processes the use of ionic liquids resulted in improved, complimentary or alternative selectivities in organic synthesis. The present manuscript reported the synthesis of multiple nitrogen containing five-membered heterocyclic compounds using ionic liquids. This review covered interesting discoveries in the past few years.

Toward Unity among Environmentalists

1995 ◽  
Author(s):  
Bryan G. Norton
Keyword(s):  
Resource Use ◽  
Wide Spectrum ◽  
Strong Support ◽  
Environmental Issues ◽  
Value Systems ◽  
Special Interests ◽  
Unified Approach ◽  
Policy Makers ◽  
The Past ◽  
Control Growth

Today, six out of ten Americans describe themselves as "active" environmentalists or as "sympathetic" to the movement's concerns. The movement, in turn, reflects this millions-strong support in its diversity, encompassing a wide spectrum of causes, groups, and sometimes conflicting special interests. For far-sighted activists and policy makers, the question is how this diversity affects the ability to achieve key goals in the battle against pollution, erosion, and out-of-control growth. This insightful book offers an overview of the movement -- its past as well as its present -- and issues the most persuasive call yet for a unified approach to solving environmental problems. Focusing on examples from resource use, pollution control, protection of species and habitats, and land use, the author shows how the dynamics of diversity have actually hindered environmentalists in the past, but also how a convergence of these interests around forward-looking policies can be effected, despite variance in value systems espoused. The book is thus not only an assessment of today's movement, but a blueprint for action that can help pull together many different concerns under a common banner. Anyone interested in environmental issues and active approaches to their solution will find the author's observations both astute and creative.

scholarly journals Mortars with Recycled Aggregates from Building-Related Processes: A ‘Four-Step’ Methodological Proposal for a Review

2021 ◽  
Vol 13 (5) ◽  
pp. 2756
Author(s):  
Federica Vitale ◽  
Maurizio Nicolella
Keyword(s):  
Building Materials ◽  
Thermal Analyses ◽  
Construction Materials ◽  
Physical And Mechanical Properties ◽  
Research Trends ◽  
Mix Design ◽  
Recycled Aggregates ◽  
Design Parameters ◽  
Natural Aggregates ◽  
By Products

Because the production of aggregates for mortar and concrete is no longer sustainable, many attempts have been made to replace natural aggregates (NA) with recycled aggregates (RA) sourced from factories, recycling centers, and human activities such as construction and demolition works (C&D). This article reviews papers concerning mortars with fine RA from C&D debris, and from the by-products of the manufacturing and recycling processes of building materials. A four-step methodology based on searching, screening, clustering, and summarizing was proposed. The clustering variables were the type of aggregate, mix design parameters, tested properties, patents, and availability on the market. The number and the type of the clustering variables of each paper were analysed and compared. The results showed that the mortars were mainly characterized through their physical and mechanical properties, whereas few durability and thermal analyses were carried out. Moreover, few fine RA were sourced from the production waste of construction materials. Finally, there were no patents or products available on the market. The outcomes presented in this paper underlined the research trends that are useful to improve the knowledge on the suitability of fine RA from building-related processes in mortars.

The Effect of Type and Height of Piers on the Seismic Behavior of Reinforced Concrete Bridges

2019 ◽  
Vol 41 ◽  
pp. 79-87 ◽  
Author(s):  
Mohamed Cherif Djemai ◽  
Mahmoud Bensaibi ◽  
Fatma Zohra Halfaya
Keyword(s):  
Reinforced Concrete ◽  
Structural Parameters ◽  
Strong Motion ◽  
Concrete Bridges ◽  
Geometrical Parameters ◽  
Girder Bridges ◽  
Building Research Institute ◽  
Reinforced Concrete Bridges ◽  
Dynamic Analyses ◽  
Strong Motion Database

Bridges are commonly used lifelines; they play an important role in the economic activity of a city or a region and their role can be crucial in a case of a seismic event since they allow the arrival of the first aid. Reinforced concrete (RC) bridges are worldwide used type view their durability, flexibility and economical cost. In fact, their behavior under seismic loading was the aim of various studies. In the present study the effect of two structural parameters i.e. the height and the type of piers of reinforced concrete bridges on seismic response is investigated. For that reason, different multi-span continuous girder bridges models with various geometrical parameters are considered. Then, non-linear dynamic analyses are performed based on two types of piers which are: multiple columns bent and wall piers with varying heights. In this approach, a serie of 40 ground motions records varying from weak to strong events selected from Building Research Institute (BRI) strong motion database are used including uncertainty in the soil and seismic characteristics. Modelling results put most emphasis on the modal periods and responses of the top pier displacements, they show the influence of the considered parameters on the behavior of such structures and their impact on the strength of reinforced concrete bridges.

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