What is Portland Limestone Cement, and is it Becoming the New Norm?

Portland Limestone Cement, or PLC, has increased in popularity over recent years. And for good reason.

The first PLC application for paving took place in Colorado in 2007, and since then it has been the preferred product throughout the construction industry.

It was first developed in Europe in the 1960s and is now used in many countries as the preferred cement product due to the fact that it reduces the carbon footprint of a concrete mix significantly. To understand exactly how that’s possible, let’s first look at exactly what PLC is.

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What is Portland Limestone Cement?

PLC, also known as Type 1L cement, is an innovative product that is reshaping how those in the construction industry use concrete. It's a type of blended cement that contains between 5 and 15% limestone. The product itself performs the same as standard concrete but it comes with great benefits. 

What makes it so popular is that the limestone content results in a 10% reduction in its carbon footprint. This increased focus on sustainability is one of the reasons why it has grown in popularity across the US. The use of PLC has been approved by the Department of Transportation in many states as an eco-friendly alternative to traditional cement, with more expected to take the same stance in the near future. 

Not only is PLC more sustainable, but it can often be less expensive than traditional cement as well, depending on the region. This is obviously a huge benefit for those in the concrete and construction industries.

In fact, earlier this year it was announced that the costs of construction are the highest seen in more than 50 years. The costs in 2021 were over 21% higher than they were before the pandemic. This is being blamed on a number of factors, such as labor shortages, inflation, and supply chain issues. 

So, any cost savings are welcomed by all in the industry.

The Sustainability Benefits PLC Provides

When it comes to CO₂, the cement industry is a significant producer. This is due to the process of making cement, which entails firing clay, limestone and other materials in a kiln, releasing CO₂ emissions. As the material is mass-produced at enormous scale, and used to create the world's roads, dams, bridges, sidewalks, and buildings, there is a lot of focus on sustainability.

A great deal of focus continues to be applied to various aspects of construction, whether that be the use of more natural resources, reduced environmental impacts, and embodied carbon. With so much cement used in construction, it's a major area of focus in terms of its impact on the environment.

By replacing some of the clinker in the cement, which is the main energy-intensive ingredient, with limestone, you are reducing the level of carbon emissions from the cement's production. As limestone grinds finer than clinker, the result is a far denser particle packing with increased particle distribution. 

The objective of modifying the concrete mix to use lower carbon ingredients to replace the higher carbon materials has been in the spotlight for years. The biggest advantage of PLC is that it is far more sustainable than standard cement products. The fact that it can reduce a product’s carbon footprint by 10% makes it a preferred material for many in the construction industry.

The reality is that PLC is a big step towards reaching net zero.

DOT Approval Rates of PLC Increasing from Coast to Coast

The Department of Transportation is responsible for approving the use of PLC in various states. The main reason they approve of its use is due to the sustainability benefits it provides, as mentioned above. That said, it's not the DOTs that are driving its adoption across the US.

While DOTs across the US are committing to PLC, it's those in the industry that are the biggest advocates for change, using PLC as part of their own focus on bringing more sustainability practices into construction.

In fact, many concrete producers who are CarbonCure suppliers use PLC in their CarbonCure mixes for stackable benefits and an even more sustainable product. 

Will PLC Soon Be the New Norm in North America?

PLC is becoming increasingly popular across the US and many producers are choosing to use it as their primary product. 

There are some areas where PLC is the only available option, such as Colorado and Texas. In these states, the DOTs have approved its use and producers have committed to using it in their mixes.

Further, an increasing number of cement producers across the US have committed to 100% PLC. With the spotlight on sustainability in the construction industry set to increase, we can expect more producers to make the shift. 

Download eBook

Finding out more about PLC

If you would like to find out more about PLC and all of its benefits, download this free eBook based on the webinar hosted by Professor Doug Hooton, PhD, the NSERC/CAC Industrial Research Chair in Concrete Durability and Sustainability at the University of Toronto.

For decades, Dr. Hooton has researched ways to reduce the greenhouse gas emissions associated with concrete infrastructure. He has informed the specification codes associated with the American Concrete Institute, the ASTM standards and the Canadian Standards Association.

In the book, Dr. Hooton explains that despite concrete being low on the embodied carbon and energy scale, it is a problem because it is the most used building material in the world. He also shares key insights into how the construction industry can reduce CO₂ emissions from concrete.

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