Reducing Concrete’s Carbon Footprint: A Guide to Sustainable Construction

Why concrete has a carbon problem

Cement production drives 90% of concrete’s emissions, with the process releasing approximately 1 pound of CO2 for every pound of cement produced. This occurs through two primary mechanisms: chemical decomposition of limestone during clinker production (60-70% of emissions) and fossil fuel combustion to heat kilns to 2,642°F (30-40% of emissions).

To help put this in perspective, one cubic yard of traditional concrete emits about 400 pounds of CO2. A standard 20×20-foot driveway produces emissions equivalent to the average home’s energy use for over a month. These numbers show why the Global Cement and Concrete Association has committed to achieving net-zero emissions by 2050.

It’s a huge challenge, but also a huge opportunity. The National Ready Mixed Concrete Association reports that their members have already lowered their carbon footprint by 21% in seven years through strategic improvements, proving that significant progress is achievable within existing business models.

Understanding embodied carbon in concrete

Concrete’s carbon footprint mostly comes from embodied carbon —the total CO2 emissions from extracting raw materials, manufacturing, transporting, and installing concrete in a building. Unlike operational carbon (emissions from heating and cooling buildings), embodied carbon is locked in from day one and can’t be reduced later. For a typical commercial building, concrete can represent 50% or more of the structure’s total embodied carbon. That’s why choosing lower-carbon concrete options today matters so much—these decisions impact the environment for the entire life of the structure, which could be 50 to 100 years or more.

Proven methods to reduce concrete’s carbon footprint

Supplementary cementitious materials lead the way

One of the fastest ways to cut carbon is with supplementary cementitious materials (SCMs), like fly ash and slag. These materials work simply by replacing a portion of cement in concrete mixes while maintaining or even improving performance.

Fly ash, a byproduct of coal power generation, is now used in 60% of modern US concrete mixtures. When fly ash is used to replace cement content, it can also reduce water demand in the mix. 

The newest breakthrough is Limestone Calcined Clay Cement (LC3), which can reduce CO2 emissions by 40% compared to conventional cement. This alternative technology replaces 50% of clinker with calcined clay and ground limestone, offering a scalable solution as global infrastructure demands grow. Research is advancing quickly, with novel electrochemical processes under development that could further reduce emissions while potentially creating valuable byproducts. 

New cement types open doors for sustainability gains

The adoption of Type IL cement (Portland Limestone Cement) is gaining speed across North America, allowing up to 15% limestone content in cement production. This simple change can reduce carbon emissions by while maintaining performance standards.

Drawbacks to Type IL cement have been that it requires higher water demands, resulting in lower strength. Also, many have noticed Type IL cement means concrete with finishing problems, in particular, shrinkage cracks. Adding reinforcement fibers, like glass fibers or polypropylene fibers, can help solve the strength and shrinkage issues.  As a growing number of projects specify Type IL cement, the opportunity grows for complementary technologies that enable you to double down on concrete performance and sustainable construction goals.

Carbon capture and utilization technologies

Carbon capture, utilization, and storage (CCUS) stand to reduce cement industry emissions by 36%, representing the largest single lever for decarbonization. Norway’s Brevik cement plant became the world’s first commercial-scale facility to implement this technology in 2024, capturing 90% of its CO2 emissions. And North American cement producers are following suit, with companies like Ozinga investing in the continent’s largest low-carbon cement mill—demonstrating that industry leaders aren’t waiting for regulations to drive change.

Recycled aggregates and circular economy approaches

 The recycled aggregates market is growing quickly, expanding from $7.7 billion in 2020 to a projected $13 billion by 2028. Using 100% recycled aggregates can reduce Portland cement content by 60%, leading to 73.8 tons of CO2 savings in typical office buildings. 

Construction and demolition (C&D) waste recycling creates substantial environmental and economic benefits. Recycling 1.3 tons of construction waste saves 221.3 lbs of carbon emissions while supporting 175,000 jobs across the recycling industry in the United States alone. 

The circular economy approach extends beyond aggregates to innovative approaches like recycled fiber reinforcement, which transforms waste materials into high-performance concrete additives while diverting materials from landfills. 

Fiber reinforcement: A sustainable concrete solution with time-saving benefits 

Fiber reinforcement represents a unique opportunity: enhancing concrete’s performance and durability while saving time on the jobsite and improving safety. Traditional wire mesh installation poses significant hazards, including cuts, puncture wounds, and tripping hazards that contribute to approximately 28,000 concrete-related injuries annually among 250,000 construction workers.

In cases where it can replace wire mesh, fiber reinforcement reduces these risks by being mixed directly into concrete, in some cases removing the need to handle, position, and secure heavy wire mesh rolls. This approach prevents impalement hazards and reduces fall risks associated with working around elevated reinforcement materials and stepping around metal grids. Integrating fiber reinforcement into the mix is also much less time-consuming than transporting, managing and laying out wire mesh on a job site, enabling crews to move more quickly to the next project. 

The recycled fiber advantage 

Recycled content fibers bring new environmental benefits while still delivering the performance contractors expect from traditional reinforcement fibers, like enhancing concrete’s strength and durability. These materials divert waste from landfills, reduce demand for virgin materials, reduce energy consumption, and support circular economy principles that keep resources in productive use.  

Wind turbine blade recycling is a great example of the circular economy in action. As turbines reach their 20-25 year lifespan, approximately 43 million tons of blade waste will accumulate globally by 2050. REGEN Fiber has developed a patented mechanical recycling process that converts blades into high-performance reinforcement fibers with unique advantages that solve the wind industry’s biggest challenge while reducing embodied carbon in concrete. Using these products (which are made in the USA from domestic and global materials) helps secure the future of sustainable green energy, which closely aligns with the objectives of low-carbon construction. Beyond sustainability, this approach delivers clear functional advantages, too.

Unlike virgin fibers that ball up when mixed or poke through the surface, REGEN Fiber’s epoxy-coated fiberglass recycled fiber distributes evenly throughout concrete mixtures and leaves a smooth surface during finishing.  

Implementation strategies for sustainable concrete 

Industry leadership and corporate commitments are driving the adoption of sustainable concrete practices. Major corporations with sustainability pledges are requiring low-carbon materials today.  These promises outlast election cycles. Companies have to answer to shareholders, customers, and employees who want green policies. 

To act now, focus on specification changes that prioritize performance over prescriptive requirements. Switching from minimum cement requirements to compressive strength requirements can reduce cement content while meeting structural needs. This approach enables greater use of SCMs and recycled materials without compromising safety or durability. 

Optimized mix designs can reduce concrete volume needs by 10-15% through improved structural efficiency. Combined with offsite construction methods that reduce waste by an additional 10-15%, these approaches deliver significant environmental benefits while often reducing project costs. 

Building Green is Good Business

There’s also a business case for sustainable concrete practices. Boston Consulting Group research shows that investments in greener cement provide greater greenhouse gas reductions per dollar than many other green technologies. The recycled aggregates market’s 6.8% annual growth rate reflects strong economic fundamentals supporting environmental benefits. 

LEED certification requirements and corporate sustainability commitments create market demand for sustainable materials, often commanding price premiums that offset any additional costs. Organizations meeting sustainability requirements position themselves competitively for green building projects and private sector contracts with companies that have made public carbon reduction and climate change pledges.

Construction efficiency improvements from technologies like fiber reinforcement reduce labor costs while improving safety outcomes. Eliminating wire mesh installation saves time and reduces injury-related expenses, creating measurable lifecycle value beyond environmental benefits. 

The Path to Net-Zero Concrete

Reducing concrete’s carbon footprint requires a comprehensive approach combining the proven technologies of today with tomorrow’s emerging eco-friendly innovations. From supplementary cementitious materials providing immediate 40-50% emissions reductions to recycled reinforcement fibers offering both environmental and safety benefits, solutions exist across the entire construction value chain. 

Bottom line: sustainability and performance can go hand-in-hand. While political landscapes will shift, as they always have, the construction industry’s sustainability commitments are steadfast—driven by corporate pledges, consumer expectations, and the fundamental business case for efficient, durable infrastructure. Companies that have promised carbon neutrality to their shareholders and customers are not reversing course, ensuring demand for sustainable and renewable construction solutions.  

The concrete industry’s commitment to net-zero emissions by 2050 is ambitious AND achievable through technologies and practices available right now. Success depends on what each solution can deliver and where its limitations are, while maintaining the safety and performance standards that protect lives and enable top-quality infrastructure development. 

There’s never been a better time to start offering lower-carbon concrete.  

So—where will you start? And what will you do with your early adopter advantage?