New approach suggests path to emissions-free cement

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MIT researchers find a way to eliminate carbon emissions from cement production -- a major global source of greenhouse gases.

David L. Chandler | MIT News Office
September 16, 2019

It's well known that the production of cement -- the world's leading construction material -- is a major source of greenhouse gas emissions, accounting for about 8 percent of all such releases. If cement production were a country, it would be the world's third-largest emitter.

A team of researchers at MIT has come up with a new way of manufacturing the material that could eliminate these emissions altogether, and could even make some other useful products in the process.

The findings are being reported today in the journal PNAS in a paper by Yet-Ming Chiang, the Kyocera Professor of Materials Science and Engineering at MIT, with postdoc Leah Ellis, graduate student Andres Badel, and others.

"About 1 kilogram of carbon dioxide is released for every kilogram of cement made today," Chiang says. That adds up to 3 to 4 gigatons (billions of tons) of cement, and of carbon dioxide emissions, produced annually today, and that amount is projected to grow. The number of buildings worldwide is expected to double by 2060, which is equivalent to "building one new New York City every 30 days," he says. And the commodity is now very cheap to produce: It costs only about 13 cents per kilogram, which he says makes it cheaper than bottled water.

So it's a real challenge to find ways of reducing the material's carbon emissions without making it too expensive. Chiang and his team have spent the last year searching for alternative approaches, and hit on the idea of using an electrochemical process to replace the current fossil-fuel-dependent system.

Ordinary Portland cement, the most widely used standard variety, is made by grinding up limestone and then cooking it with sand and clay at high heat, which is produced by burning coal. The process produces carbon dioxide in two different ways: from the burning of the coal, and from gases released from the limestone during the heating. Each of these produces roughly equal contributions to the total emissions. The new process would eliminate or drastically reduce both sources, Chiang says. Though they have demonstrated the basic electrochemical process in the lab, the process will require more work to scale up to industrial scale.

First of all, the new approach could eliminate the use of fossil fuels for the heating process, substituting electricity generated from clean, renewable sources. "In many geographies renewable electricity is the lowest-cost electricity we have today, and its cost is still dropping," Chiang says. In addition, the new process produces the same cement product. The team realized that trying to gain acceptance for a new type of cement -- something that many research groups have pursued in different ways -- would be an uphill battle, considering how widely used the material is around the world and how reluctant builders can be to try new, relatively untested materials.

The new process centers on the use of an electrolyzer, something that many people have encountered as part of high school chemistry classes, where a battery is hooked up to two electrodes in a glass of water, producing bubbles of oxygen from one electrode and bubbles of hydrogen from the other as the electricity splits the water molecules into their constituent atoms. Importantly, the electrolyzer's oxygen-evolving electrode produces acid, while the hydrogen-evolving electrode produces a base.

In the new process, the pulverized limestone is dissolved in the acid at one electrode and high-purity carbon dioxide is released, while calcium hydroxide, generally known as lime, precipitates out as a solid at the other. The calcium hydroxide can then be processed in another step to produce the cement, which is mostly calcium silicate.

The carbon dioxide, in the form of a pure, concentrated stream, can then be easily sequestered, harnessed to produce value-added products such as a liquid fuel to replace gasoline, or used for applications such as oil recovery or even in carbonated beverages and dry ice. The result is that no carbon dioxide is released to the environment from the entire process, Chiang says. By contrast, the carbon dioxide emitted from conventional cement plants is highly contaminated with nitrogen oxides, sulfur oxides, carbon monoxide and other material that make it impractical to "scrub" to make the carbon dioxide usable.

Calculations show that the hydrogen and oxygen also emitted in the process could be recombined, for example in a fuel cell, or burned to produce enough energy to fuel the whole rest of the process, Ellis says, producing nothing but water vapor.

In a demonstration of the basic chemical reactions used in the new process, electrolysis takes place in neutral water. Dyes show how acid (pink) and base (purple) are produced at the positive and negative electrodes. A variation of this process can be used to convert calcium carbonate (CaCO3) into calcium hydroxide (Ca(OH)2), which can then be used to make Portland cement without producing any greenhouse gas emissions. Cement production currently causes 8 percent of global carbon emissions.

In their laboratory demonstration, the team carried out the key electrochemical steps required, producing lime from the calcium carbonate, but on a small scale. The process looks a bit like shaking a snow-globe, as it produces a flurry of suspended white particles inside the glass container as the lime precipitates out of the solution.

While the technology is simple and could, in principle, be easily scaled up, a typical cement plant today produces about 700,000 tons of the material per year. "How do you penetrate an industry like that and get a foot in the door?" asks Ellis, the paper's lead author. One approach, she says, is to try to replace just one part of the process at a time, rather than the whole system at once, and "in a stepwise fashion" gradually add other parts.

The initial proposed system the team came up with is "not because we necessarily think we have the exact strategy" for the best possible approach, Chiang says, "but to get people in the electrochemical sector to start thinking more about this," and come up with new ideas. "It's an important first step, but not yet a fully developed solution."

The research was partly supported by the Skolkovo Institute of Science and Technology.

Generational and Inclusive Design

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Generational, Ageless Living, Intergenerational and multigenerational design are terms used to describe design approaches to new buildings and retrofitting old to accommodate the needs of its occupants from infancy through old age. While a trend in creating livable spaces for the elderly (most specifically Baby Boomers) has been in place, a more recent perspective promotes creating space for multi generations of occupants living comfortably together at any one time as well as designing for a single family to age from infancy through old age in the same space over time. Regardless of the term used, the creation of livable spaces to accommodate very young to very old under the same roof is catching on.

To take things a step further, Inclusive and Universal Design refers to broad-spectrum ideas meant to produce buildings, products and environments that are inherently accessible to older people, people without disabilities, and people with disabilities. Every design decision has the potential to include or exclude someone. Inclusive and Universal design choices emphasize the understanding how diversity should contribute to these decisions and focuses on including as many people as possible. Users' capabilities, needs and ambitions are driving forces behind sound design selections.

We proudly offer Generational Design courses from a variety of writers with fresh perspectives.

Safety Month and Texas Electrical Continuing Education

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If you're heading for a license renewal deadline, you're probably thinking about NEC code updates and passing the test more than you're thinking about national safety month, but the two subjects are more connected than you might think. After all, electrical code is all about safety and electrical license renewal is about staying informed on the latest safety measures.

TDLR Laws and Safety 2018

Staying on top of Texas electrical code changes from 2018 start with safety. To successfully renew your license, you'll need to be able to identify electrical hazards, describe how to prevent electrical accidents and what to do if an accident or a risk is identified.

Completing a TDLR Laws and Safety continuing education course is a good way to make sure you're up on the newest rule changes and gather CEU credits for recertification.

NEC 2017 Code Changes

Some changes to the NEC 2017 standards involve configurations you're likely to see all the time. For example, there are changes around fire alarm systems, optical fiber cables and raceways. Other NEC changes are a little less common for a general electrician. For example, you'll want to stay informed on changes to code regarding swimming pools, photovoltaic (PV) systems and fire pumps; which aren't always involved on an average electrical job.

Staying up to date on both TDLR and NEC code changes makes sense for license renewal and safety month is a perfect time to do so.

You can see a full list of Texas electrical continuing education courses on the training portion of the website and feel free to get in touch with questions.

Healthy House Paint

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Healthy House Paint

Three coats of Healthy House Paint by Denver-based nanoscience company Synavax don't just embellish a house--they insulate it. The zero-VOC coating uses patented technology that incorporates a nanocomposite that the company calls Hydro-NM-Oxide, which lessens heat loss and gain by up to 34.8 percent, according to third-party testing.

Like any paint, it can be rolled, sprayed or brushed on (inside or outside) to achieve lower energy bills (customers report 20% - 40%+ reduction), prevent mold and mildew growth, reduce your carbon footprint, give surfaces a "stay-clean" quality, protect exteriors from UV damage and fading, reduce moisture damage issues, and not add to air pollution with no and low VOC products.

"In our patented coatings and paints, we've managed to incorporate that special insulating component (which is also water-repelling) into a coating system that allows it to be easily painted onto surfaces," says Synavax vice president of training and specifications Francesca Crolley.

It is suitable for indoor and outdoor applications on multiple surface types, including wood, brick, and drywall. The paint is currently offered on the company's website in clear, white, and custom colors to coat fresh or already painted surfaces.

You can choose home insulating coatings in clear, white (tintable) or in a custom color that can deliver to your door. All of them are low odor. Occasionally there may be a very slight "wet paint" smell when the paint is first applied, and this will go away once it dries. The paint is completely non-toxic, and water based.

For more information go to:

Apps of Interest October 2017 Edition

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Angle Meter Pro:

This digital tool allows you to measure the angles or slopes on the job with a high degree of precision. You can work it through the app, a tablet or cell phone camera. You will be able to measure a variety of slope forms and can choose to directly measure the surface by the second mode, which makes it relatively easy to measure up, or to measure the angle of the target a short distance away from you.

iTunes $1.99

GooglePlay - Free


PlanGrid is an intuitive application allowing you to share plans, annotations, photos and reports instantly. Use PlanGrid to reduce repeated trips to the trailer, minimize rework, and find answers faster through instant collaboration. Keep everyone on the current set and manage all your construction documents without relying on paper.

iTunes - Free

Google Play - Free

Pitch Gauge:

Use Pitch Gauge© to calculate the total size and slope of any roof. It includes two digital slope finders and a square calculator. Find slope without ever leaving the ground using camera-mode. Then, take a picture with the pitch reading and current address stamped onto it, and attach it to an email for your own or the insurance company's documentation.

iTunes - Free

Google Play - Free


Ride sharing isn't just for people any more. Now, builders, remodelers, and DIYers can schedule a truck through a new free iOS app.

Since its recent launch, Truxx has been used for everything from moves across town to large purchases at retail stores or online community sites like Craigslist. Just like on-demand ride-sharing services such as Uber or Lyft, Truxx enables users to schedule and rate drivers, make cash-free payments, and provides driver background checks. Truxx also has unique features like driver location services, in-app messaging, and gives drivers the ability to book multiple jobs.

iTunes - Free

Google Play - Free

Apps of Interest April 2017 Edition

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Job Site Communication:


Keeping everyone on the same page and in the know is hard. But streamlined, effective, re-al-time communication means fewer errors, a better experience for your employees and cus-tomers and a better reputation. BuilderTREND was created especially for the construction workspace to connect everyone involved in a project (from the builder, to the contractor, to the customer) with every single detail--every step of the way. It features automatic updates and real-time notifications that allow builders to manage projects, collaborate, and com-municate with subcontractors, vendors, project managers, and customers.

Features • Easily document and share job logs from the field--record notes using voice to text (or your keyboard), and add a progress photo each step of the way • Assign to-do items to yourself, your workers, or your associates • Share and annotate photos and blueprints right from the job site • Use in-app messaging (fast, easy, and organized) to communicate quickly; search by top-ic, leave a comment, and restrict who can (or can't) see your response • Coordinate with subcontractors and trade partners--send big requests and purchase or-ders straight from your mobile device • Track and accept online payments

Project Management:


Ever wish you had an extra project manager on site to help you evaluate, bid out, and complete a project? Now you have one in your pocket. Co-Construct is a project management tool for home builders and remodelers that stores all the information you need to build or remodel a home. The app can be used at every stage of a project's lifecycle, from the initial bidding process through to completion and beyond. Use it to create project estimates and proposals, invite and manage bids from subcontractors, store all your plans and specifications, track project costs, schedule and manage jobs on the worksite, create and manage change orders, update your accounting data, and manage punch list items on completed projects that are still under warranty.

Features • Reduces paperwork at every stage of your project: from proposal to completion. • Improves communication with your clients and subcontractors. • Includes bid management, cost management, and labor management tools. • Syncs with QuickBooks to create invoices and cost forecasts. • Allows you to manage all your projects from a single dashboard.


AutoCAD 360

If you are an engineer, it is highly likely you use some form of AutoCad in your daily life. This design software makes sketching out your ideas a breeze and it's also offered in a mobile app allowing you to view and edit DWG files on your mobile device.

Apps of Interest February 2017 Edition

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JobFLEX Google Play

Being able to quickly and easily create estimates for customers using an estimating app is critical. The difference between gaining a new client and losing a potential job often hinges on how quickly and professionally you can turn that estimate around. With JobFLEX, there's no tech savvy needed. Deliver estimates on the spot, with or without a cellular connection. Create and edit customizable forms, then just drag and drop line item costs, materials, and photos. When you're finished, preview, email or print the estimate with one tap.


iEngineer Perfectly Simple Apps, LLC iTunes

If you need a screw database, iEngineer is the answer. The app has a comprehensive list of U.S. and metric screws, including dimensions for different head styles, material grades, and different screw sizes. For U.S. screws, the app has a catalog of 93 different screws from #0 to 4-in. They are categorized by their nine different head styles including flat, oval, hex, and truss along with 29 material grades ranging from different SAE and ASTM standards. The metric catalog has over 200 metric screws ranging from M1.0 to M100. The most helpful information comes in the form of advised torque, lubricated torque, and clamping force for the screw chosen. This will help engineers determine installation requirements.


MyPantone iTunes Google Play

For over 50 years Pantone has been the international language of color. This app now gives you access to the entire Pantone catalogue of over 13,000 colors and makes it easy to create and share color palettes. Capture and extract colors from photos and snap to the closest Pantone color.


Arc Flash Analytic Arcad Inc. iTunes Google Play

The app has been developed based on IEEE 1584 Guide for Performing Arc-Flash Hazard Calculations as an easy to use and comprehensive tool for calculating incident energy and arc flash boundary, determining limited, restricted, prohibited approach boundaries and hazard risk category required by NFPA 70E, NEC / CEC and OSHA when work is to be performed on or near the energized equipment.

Apps of Interest September 2016 Edition

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Field Supervisor $0.00

Field Supervisor from Bentley Systems provides construction field workers with onsite views, personalized for their specific project roles, into multiple project data, ensuring real-time decisions are made using the most relevant and current information. At the same time, it eliminates the risk of relying on potentially outdated printed materials. Field Supervisor connects to multiple project data sources, including Bentley's ProjectWise system of collaboration servers and services and eB, which controls information throughout the lifecycle of change. This allows users to directly access secure electronic documents for inspection and confident decision making.

Archisketch: Sketch and Doodle to Scale

Urban Design

Free - $9.99

Archisketch, formerly Archipad, is a new iPad sketching app by Urban Design that's ideal for architects, interior and product designers. While there are many sketching apps on the market, what makes Archisketch unique is that it's scale aware. Once you set the scale of your drawing sheet, the drawings will be completely scaled to the real world, even down to the line thickness. In addition, Archisketch has many other features that cater to architects and designers, including layer rotations, shape and freehand drawing tools and more. Archisketch is easy enough to use for professionals and non-professionals alike. Similarly, it has a tiered pricing structure--it's free to download for small projects. As projects become more complex, the user can buy a subscription for however long or short they need the app for.

Engineering Professional

By Multieducator Inc $17.99

ENGINEERING PROFESSIONAL combines all of the formulas from our Chemical, Civil, Electrical, Environmental, Hydrology and Mechanical Engineering formulator apps. This program is perfect for any Engineering student. Over 650 formulas allow you to determine everything from calculations on shafts to calculation on loads on beams. This one app lets you calculate the widest range of calculations. In addition there are 100 conversion formulas, as well as a section for determining Area formulas.

All formulas can be saved. You can easily access recent or favorite formulas. You can also e-mail the results from any formulas. While we regularly upgrade and add formulas to the underlying programs, ENGINEERING PROFESSIONAL will be expanded as well. We expect ENGINEERING PROFESSIONAL to eventually grow to over 1,000 formulas.

Translucent/Light Transmitting Concrete

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Translucent concrete (light-transmitting concrete) is a concrete based building material filled with optical fibers that run from one end of a poured piece of concrete to the other.

Effectively transmitting light due to fibers running through prefabricated blocks and panels, concrete is given a new look without sacrificing its strength and durability. The fibers can transmit light to over 50 feet and, as they occupy only a small percentage of the total concrete block or panel, they do not significantly affect the structural capabilities of the poured pieces. This results into a certain light pattern on the other surface, depending on the fiber structure. Shadows cast onto one side appear as silhouettes through the material. The fibers can also be used to create lettering, pictograms and "light patterns" in the concrete. Colors and light remain remarkably consistent from end to end, but with a natural variation from the pouring process that actually softens the effects considerably.

More information may be found at:

Alternative Ways to Deal with a Wall Base

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Baseboards are traditionally used to cover the intersection between walls and floors. They protect against damage from feet, vacuum cleaners and other objects and they hide imperfections in levels and finishing. But they also collect dust, may not be the most attractive finish and you may want to consider alternatives.

Applied Base
The baseboard is an applied base in its most traditional form, typically a 3.5 inch profile fixed at the base of the drywall where it meets the floor. However, you can have variations that include:

  • A larger baseboard that is both taller and thicker than it needs to be in order to add presence
  • A smaller and thinner baseboard that retains its protective functionality but is less significant within the overall design
  • Low profile, square baseboards for a more modern effect.
Depending on your choice, the baseboard can be emphasized by detailing or coloring so it stands out or can be the same color as the wall or floor. It can be in various materials and can be designed to align with doorframes, windowsills or cabinets.

Flush Base
The baseboard is incorporated into the base of the wall rather then being fixed to its surface. It therefore still fulfills the function of protecting against knocks but minimizes the problem of dust collection.

As for an applied base, it can be in various materials and colored to either blend in with the wall or floor, or to contrast as a feature. A flush base can provide a clean transition to stairways or similar areas.

A flush base is more complex to install, with the need to keep the wall and base properly aligned. The finished wall surface and the base should also be fixed to the same underlying material to prevent cracking of the joint over time.

Rather than hiding the joint between the floor and the wall, a reveal seeks to emphasize it. A clean edge is provided as a shadow line, created by inserting a strip of metal or plastic between the floor and the wall base.

The reveal itself can contrast with or match the color of the wall and requires both intersecting surfaces to be precisely aligned for a clean finish. It is usually only suitable for areas that aren't likely to take a lot of knocks.

This is the ultimate minimalist approach, with nothing covering or filling the gap between the wall and the floor. It provides a clean look with fewer areas to collect dust and fewer materials for the installation.

This approach does, however, have drawbacks:
  • The wall has to be properly finished and the floor must be absolutely even to create the required clean line
  • The joint between the floor and wall needs to be kept open to allow free movement
  • Damage to the wall base is more likely.
Added Complexity
To achieve the finish you require, care must be taken with planning and installation. The alternatives can add complexity as well as cost to the project so you must think through what you're trying to achieve and test the outcome thoroughly.

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