Thoughts on the Engineering Industry

A blog covering engineering, technology and business topics

Archive for the tag “sustainability”

Benefits and Implementation of “Green” Urban Design

Hello everyone! I hope everything is going well.  This week I would like to talk about the incorporating “green” elements to city planning. I read an article a while ago that pointed out some interesting aspects of city life.  Most people who live in cities don’t notice nature around them in cities, instead they go on vacation to find nature.  Furthermore, more and more of the world’s population lives in cities.

This article listed the following benefits of the inclusion of nature into a city:

  • improved health and lifestyle
  • increased lifespan
  • reduced stress and aggression

Traditionally, the use of green space has been an aesthetic concern rather than a requirement for psychological health.  In addition to that, most urban planners haven’t claimed ownership of the issues related to lack greenery in the cities.  However, that is changing in Detroit, Europe and Singapore.  The researchers believe that greenery needs to be incorporated into urban planning from the ground up.

The article recommends that urban planners start incorporating the following elements to urban planning:

  • to consider the value of the greenery in an area before starting construction
  • to cluster homes and leave some easily accessible locations with greenery or natural elements around neighborhoods for city dwellers
  • to quantify the costs/benefits of different types of greenery and invest in them accordingly

While I think that some of the contributors come across as overzealous at moments, I agree with the concept.  Some of my most relaxing moments when I lived in Arlington, TX were the times I spent running at River Legacy Park.  It was a park that had a great section of in which I could loose myself in nature and reach a zen-type running state.  This article highlights benefits of incorporating nature that I have experienced myself.

What are your thoughts on incorporating nature into cities?  Do you agree with the articles assessment?  What would you do to incorporate nature into cities?  If you enjoyed the post, like it and share it with your friends.  Thank you for your time and have a good week!

Source

Anderson, Erin, “How Green Cities are Better for us Physically and Psychologically”, The Globe and Mail, July 5, 2014, http://goo.gl/PgM8Da

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Benefits of Reusing Composite Shingles in Asphalt Roadway Construction

Hello everyone! I hope y’all have been doing well.  Today, I want to talk about an interesting innovation I read about the construction of O’Hare Airport. (http://goo.gl/WjI8Ek)  They collected used composite asphalt shingles and used them as part of the asphalt binder in the runway and various road type structures for the facility.  In this post, I will outline the process and the benefits.

 
The process:
Old Shingles Are Collected:
First, shingles are collected for reuse in the system.  At first, there weren’t any incentives added to motivate people to recycle used shingles.  However, some incentives have been created through different programs in various locations – all them outlined in the article.  One of them is a ban on sending large amounts of shingles to the landfill.  Another concept is an increased charge for disposing of shingles as compared to providing them for reuse.  The only exception is shingles that incorporate asbestos in their production and various limitations are discussed for reducing that risk.  Overall, the incentives seemed effective in my opinion.
 
Shingles are mixed into a pure asphalt binder:
The next step is that shingles are ground up and melted.  Once melted, this product can be added to the pure asphalt binder to increase the volume of this asphalt binder product.  At O’Hare airport, the shingles made up a 3% percent portion.  This didn’t make a huge dent in the budget but depending on the project it could reduce costs more.  Statistics and comparisons are provided in the article.
 
Asphalt is Laid Like Normal:
The asphalt binder and resulting asphalt is used like before.  As long as any differences in material properties are accounted for, the design and construction remains the same.  This results in an easy implementation on the construction and design side of the process.
 
The Benefits:
Reduced Use of Oil:
Oil is a precious commodity; anytime it’s usage is reduced, I consider it a good thing.  Along with that, it is easier to get a hold of used shingles than oil.  For both of these reasons, I consider the reduced oil usage a considerable benefit.
 
Reduced Cost:
The cost of using reused shingles is lower than using a pure asphalt binder.  Unless the scale is large, it is a minimal cost difference.  However, considering the scale of infrastructure cost these days and the amount of repairs needed, the scale is large enough that it would make a difference.
 
Reduced Waste:
These shingles, if not used in this capacity, would most likely be going to a landfill.  The lack of landfill space and shear quantity of human waste going to landfills is a current issue and reducing the amount from the housing would be a large contribution towards reducing that waste.
 
What is your opinion on the usage of this mixed asphalt binder?  Does it provide enough benefits to outweigh the cost and effort of changing the process?  Are there any noteworthy drawbacks or additional benefits not mentioned?  Thanks for your time and have a good week!
 
Sources:
Jon Hilkevitch, “Getting Around: Old Shingles Get New Life on O’Hare Runway”, Chicago Tribune News, June 30, 2014, http://goo.gl/WjI8Ek
 
Image Source:
“Why Homeowners Should Choose Asphalt Roofing Shingles Recycling”, Asphalt Roofing Shingles Recycling, October 18, 2012, http://goo.gl/u9l7cD

Concrete Eating Robots: A More Efficient Method of Breaking Down Concrete?

 

     Hello everyone.  I hope everything is going well.  I had a good Easter weekend with my family and I’m feeling rested after a busy week.  Today, I would like to talk about an innovation I read about a few weeks ago which is called a “Concrete Eating Robot” as described in a blog post by Peloton Land Solutions.

     The Concrete Eating Robot is a system which uses a high pressure water jet to break down concrete rather than using a wrecking ball or something else to crush concrete.  The water/concrete slurry is then collected to reclaim the reusable materials.  The clean aggregate can be used in other concrete mixes.  The water is reused by the system so that a large of amount of water isn’t wasted in the process.  And the clean and reusable rebar beneath the concrete can be pulled apart for use in other structures.  The only waste that I could find according to the article by Peloton Land Solutions is the cement mixture that can’t be reused.

     This invention has some very good benefits in that the rebar and aggregate can be reused in a very efficient manner.  However, cement is the least sustainable product required for concrete construction.  And in this case, I didn’t see a method for recycling cement which could make this a critical issue.  Depending on the situation, this could negate some of the benefits to the point that this invention might not be worth the investment.  For example, if this is a case where a high amount of cement is required and aggregate can be easily procured locally for any new construction, the cost benefit ratio might tilt back towards a more traditional method.  If this is a low to zero cement usage concrete in an area where the required aggregate isn’t easily obtainable, this would be a better situation for something like this.

   Here is a more detailed article on the device: http://goo.gl/SWDwN2

   What is your opinion on this invention? Do you see it being used regularly in the future?  Thanks for your time and have a good week!

Resources:

Peloton Land Solutions, “Concrete Eating Robots?”, March 3rd, 2014, http://goo.gl/Y920hK

CoExist Blog, “This Concrete Eating Robot Can Recycle an Entire Building on the Spot”, April 16th, 2014, http://goo.gl/SWDwN2

Potential Applications of Cellulose Nanocrystals in Structural Engineering

Hello everyone! Today, I am going to take a break on my Karuna House series and write a post about cellulose nanocrystals.  Cellulouse nanocrystals are the material that gives plants and trees their stiffness. Their dimensions are 3 nanometers wide by 500 nanometers long – about .1% the width of a grain of sand.  They can be easily harvested with a sustainable process and can be produced from paper waste as well.  A recent study by Purdue University has found that these nanocrystals are light weight, have high strength, are highly resistant and have the stiffness of steel.  “It (the research) is also the first step towards a multiscale modeling approach to understand and predict the behavior of individual crystals, the interaction between them, and their interaction with other materials,” Zavattieri said. “This is important for the design of novel cellulose-based materials as other research groups are considering them for a huge variety of applications, ranging from electronics and medical devices to structural components for the automotive, civil and aerospace industries.”  The article shown in the link here, http://goo.gl/8Pl8LB, provides a quick overview of characteristics with extremely basic explanations in regards to applications and I am going to expand on possible applications as they pertain to structural engineering.

Organic Polymer for Concrete:

     Fiber reinforced concrete can be designed to reduce the amount of steel required.  In this way, cost and heavy material requirements can be reduced in the construction process.  I believe that cellulose nanocrystals can be used in the same way.  They can be placed in concrete and improve the tension strength where needed.  These also have the added benefit of being more sustainable and less expensive in regards to material accessibility as compared to fiber reinforcement.  That being said, it is not clear if the cost of the production once the material is obtained would be out-weigh the cost savings in accessibility.  More research and practical application of the production process is needed to determine that.

Reinforcement Against Cracking:

A very common issue with concrete infrastructure is cracking.  Currently, when cracking starts occurring at the base of a beam, a method where steel reinforcement is bolted into the concrete is used to prevent further expansion of the cracks.  While it is an efficient solution in regards to time and money, steel is not as environmentally friendly a material.  Along with that, once research into production and application is completed, the amount of time and money can be reduced to that of the steel reinforcement method.  This means that an approach where an organic polymer sheet covered by a layer shotcrete could be a better solution at that point.

Additional Reinforcement for Timber Structures:

Engineered lumber is a recent development in timber design.  These are basic timber building elements that are created from pieces of timber.  Some good examples of this are cross laminated timber/particle board panels and glulam beams /columns.  Along with that, other applications such timber restoration apply this same concept of combining pieces of timber to create a stronger building element.  The same type of organic polymer sheet used for reinforcement against cracking could also be used to provide some extra tension strength in these situations.  This would be very beneficial in timber elements that are designed to resist high levels of flexure.  Another added benefit would be that the nanocrystals are extremely thin and can be applied in design with very tight tolerances.

Cellulose nanocrystals could have a lot promising a applications for structural engineering designs and I look forward to seeing what improvement can be made using this material.  What is your opinion on the possible applications mentioned above?  Are there any other structural engineering applications that you can see this material for?  Thanks for your time and have a good week!

Sources:

Zavattieri, Pablo. “Cellulose Crystals Are a Possible ‘Green’ Wonder Material.” Red Orbit Online.  December 17, 2013. http://goo.gl/8Pl8LB

Concrete without Cement: Creative Usage of Other Materials in Concrete

Hello, I hope everyone is doing well. There isn’t anything new going on with me – just the usual stuff.  I am finally making progress on the graduation paperwork which is good.  It would be nice to officially finish my school stuff.  Today I want to talk to you about an article I read about a structure made with concrete mix that doesn’t use cement.

This is the link to the article: http://goo.gl/7z0B7f.

The building being discussed is the Global Change Institute (GCI) building for the University of Queensland.  In trying to achieve better sustainability, Hassel in collaboration Bligh Tanner, Arup, and Medland Metropolis has used a what they call a geopolymer precast concrete which replaces cement with fly ash.  The brand name for this mixture is called Earth Friendly Concrete (EFC) and was applied in 33 precast floor beams of the GCI building.  The mixture is comprised of sand, aggregate, and a binder containing blast furnace slag and fly ash.  The removal of cement greatly reduces the carbon dioxide emissions in the creation of the concrete as a whole.  In order to further increase their sustainability, hydroponic pipes were added to the floor beams as well to improve low energy and passive cooling modes.  Bligh Tanner’s director believes this will improve the carbon emissions created by the cement production, estimated to currently be 8% of the carbon emission in construction projects.  Before this, EFC has only been used in low level applications such as ground bearing pavements and masonry blocks.  The concrete also has faster curing times which decreases production and construction costs as well.  The different chemistry also has the following benefits: low shrinkage, low heat of reaction (reduces thermal cracks), 30% higher flexural tensile strength, and higher durability.

This sounds like a good innovation in concrete design in regards to carbon emission reduction.  Blast furnace slag and fly ash have been used a long time in the creation of concrete to improve cost and production efficiency since the most difficult material to create for concrete is cement.  Along with that, there is the benefit of making use of waste from steel production plants and coal fire power plants.  However, I worry about the lack of history with the usage of this material.  Over the lifetime of the structure, we don’t know how well the binder will hold up.  Also, there might be other issues with chemical reactions over time due to elements in nature.  It has taken lots of studies and years of observations with regular concrete to discover and address the chemical issues such as salt.  Upon further research, I have also read that concrete mixtures with fly ash has been shown to have higher occurrences of sulfate degradation.  In light of these unknowns, caution should be used in my opinion.

What is your opinion on this new concrete mixture? Have you heard or read about anything else like the innovations mentioned above?  I am also rusty on my chemistry in regards to concrete, is there anything else that needs to be considered in analyzing the possible chemical degradation issues? Thank you for your time and have a good week!

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