The concrete industry is demonstrating leadership in its ability to deliver and quantify carbon reductions in the built environment, but challenges remain. Concrete represents a substantial portion—often 50% or greater—of a building’s total embodied carbon footprint. Amid growing demand for climate-resilient structures and the rise of low-carbon procurement policies like “Buy Clean,” the cement and concrete industries have committed to reducing embodied carbon. Industry-wide innovation is driving the push toward net-zero concrete, but concrete producers alone cannot solve this challenge. Architects, engineers, contractors and project stakeholders, each of whom play a crucial and interrelated role in selecting concrete products, must work together to achieve meaningful reductions in carbon emissions.

Balancing the industry’s essential role in delivering strong, durable and resilient structures with the need to reduce its carbon footprint requires more than innovation—it also demands a fundamental shift in how projects are planned and executed. 

From addressing the embodied carbon in cement to aligning design goals with construction realities, the path forward is complex but full of opportunity. One of the biggest hurdles? The gap between the estimated embodied carbon of a project during the design phase and what is ultimately built. Bridging this gap demands proactive measures, greater transparency and adoption of advanced tools, as well as the willingness to adopt all levers available to reduce emissions at every stage of the project lifecycle.

The Problem of Overlooked Overages
At the heart of the issue lies a mismatch in embodied carbon calculations along the project lifecycle. During the design stage, global warming potential (GWP) targets for each concrete element (kg CO2/m3) are determined using strength classifications, exposure requirements and projected volumes. These estimates, although informed by best practices, often fail to account for changes made during the construction phase, most commonly related to schedule considerations that may inadvertently increase the carbon intensity of the concrete used.

An example of this impact is illustrated by suspended slabs, essential in mid- and high-rise buildings. These elements are typically designed for a moderate strength (i.e., 4000 to 5000 psi) to meet structural performance requirements. However, construction schedules—which prioritize speed and efficiency—may influence contractors to choose higher early strength mixes for faster curing. This translates to higher cement content, bringing the mix strength far beyond the original design requirement (i.e., > 8000 psi). The ripple effect of such changes can dramatically raise a project's embodied carbon footprint.

Another factor is the compounding effect of over-design throughout the project value chain. Each party involved in specifying concrete tends to add various factors, which, when combined, result in mixes much stronger than necessary. This additional cement use contributes to higher emissions, underscoring the need for streamlined, performance-driven specifications early in the design process.

The concept of a carbon budget, as outlined by the ACI 323 Low Carbon Concrete code, among other guidance documents, provides a strong foundation and industry-endorsed best practice for specifying low carbon concrete. However, to close the embodied carbon gap, the concrete industry must embrace a multifaceted approach that spans realistic budgeting, forward-thinking specifications and innovative tools. Establishing accurate carbon budgets and fostering transparent planning are critical first steps, ensuring that projects account for real-world construction demands from the outset. 

Realistic Carbon Budgets and Transparent Planning
One foundation for minimizing overages starts with an honest assessment of construction demands. If the project timeline is likely to require faster-curing concrete, project teams should set embodied carbon targets using more accurate baselines. For instance, the Guideline for Specifying Low Carbon Ready Mixed Concrete, developed by the Canadian Ready-Mixed Concrete Association, advises 130% of the traditional concrete GWP values for specialty mixes. Such guidance, coupled with input from local concrete producers, presents realistic carbon expectations based on regional data.

Additionally, early collaboration between design teams and producers fosters better understanding of emissions impacts. Producers can contribute granular data about mixed designs, plant efficiencies and locally viable alternatives, making it possible to foresee whether goals are achievable with less carbon-intensive methods.

Performance-Based Specifications Over Prescriptive Design
Prescriptive requirements, such as minimum cement content mandates, limit flexibility in achieving both performance and sustainability goals. Shifting to performance-based specifications enables contractors and producers to focus on achieving key outcomes like compressive strength, durability and exposure resistance. This shift also encourages the adoption of advanced technologies and alternative materials, such as supplementary cementitious materials (SCMs) and optimized mix designs.

As design and construction teams make progress in these areas, they will begin to bridge the divide between the embodied carbon estimated during planning and the as-built carbon footprint of the completed structure, addressing the emissions that truly impact the environment. 

In addition, opportunities are created for collaboration across the supply chain. Concrete producers can work closely with designers to tailor mixes that meet both structural and environmental requirements, while contractors can adapt to real-time conditions on-site without being constrained by outdated prescriptive rules. 

By offering flexibility, performance-based specs free designers and suppliers to collaborate on low-carbon option throughout the construction lifecycle.

Optimizing Concrete Mix Designs
Optimizing concrete mix designs is a critical step in reducing the carbon footprint of construction projects while maintaining the performance and durability that contractors and designers demand. Yet, general contractors often stick with familiar mixes that they know will handle the load in tight timeframes. 

SCMs not only lower the embodied carbon of concrete but also enhance certain properties, such as durability and resistance to chemical attacks, making them ideal for a wide range of applications. For example, SCMs can be blended as ternary or quaternary mixes to balance the best of each material’s properties and deliver the desired results to suit the application. 

Reducing Risk and Enhancing Consistency
Reducing risk and enhancing consistency in concrete production and placement is critical to achieving both quality and sustainability goals. Monitoring probes embedded into concrete mixer drums, or alternative external sensor technologies, enhance batch consistency and address common issues associated with human error, such as overwatering or improper mixing which can compromise the performance and durability of the final product. 

In addition, these probe or sensor technologies can validate that the concrete is within spec upon discharge, reducing rejected loads or unexpected delays. This not only minimizes material waste and associated carbon emissions but also streamlines construction schedules. Furthermore, the data collected by these probes serve as a verifiable record of quality, offering peace of mind to contractors, designers and project owners alike.

However, the benefits extend beyond immediate quality assurance. By standardizing batch consistency and reducing variability, these digital tools can help contractors and producers build trust in low-carbon concrete mixes, which may require adjustments to traditional practices. This consistency also supports the adoption of performance-based specifications, as it provides the reliable data needed to demonstrate compliance with project requirements. Ultimately, these tools are not just about reducing risk, they are about building confidence in innovative, sustainable practices that will define the future of the concrete industry.

Relying on traditional cylinder testing often presents challenges that contribute to project inefficiencies and increased emissions. Miscast, mishandled or improperly stored cylinders frequently yield inaccurate results that fail to reflect the true strength of the in-place concrete. For example, micro-fractures in the concrete, caused by mishandling during transportation, can lead to a deceptively low-break strength.  

In response to these perceived weaknesses, concrete producers often increase cement content in their mixes as a precautionary measure to avoid low test results. While this may seem like a practical solution, the tradeoff is seen in the embodied carbon of the concrete, undermining sustainability goals and increasing costs. Additionally, reliance on cylinder testing introduces logistical challenges, such as the need for on-site personnel to cast and transport samples, as well as delays associated with waiting for off-site test results. 

The limitations of traditional testing also extend to project timelines. Cylinder break tests are time-consuming and involve multiple steps, such as casting, curing, transporting and finally testing the samples. Each of these stages introduces opportunities for error, which can result in delays or require costly re-pours if test failures occur.

Furthermore, the lag between pouring the concrete and receiving test results can obstruct critical path activities, slowing down overall construction progress.

The advent of digital tools, including maturity monitoring and AI, represents a major step forward in managing carbon and performance in real time, helping minimize waste and delays. These tools use embedded sensors to track temperature-strength relationships, providing continuous updates on curing progress. 

Maturity monitoring can significantly reduce the reliance on early-strength cylinder sampling. These systems use embedded sensors to provide real-time, site-specific measurements of concrete strength as it cures in place. This approach drastically reduces errors linked to sample handling or off-site testing and ensures strength assessments reflect actual conditions, not approximate ones. By enabling contractors to access immediate data, maturity monitoring helps reduce the lead time needed to verify strength, allowing construction schedules to move forward without unnecessary delays.

By integrating these technologies into the construction process, the industry can achieve greater efficiency and transparency, lower emissions and fewer delays, ultimately delivering projects that are both cost-effective and environmentally responsible.

Real-World Impact of Digital Solutions
Consider a high-rise building project facing tight timeline demands. Early projections estimate the carbon footprint based on traditional 28-day concrete mixes. However, with construction deadlines looming, the contractor needs faster-curing mixes to reduce formwork stripping times. By embedding maturity monitors in the slabs, the contractor can verify that strength outcomes are met during the required timeframe using a mix optimized for their application, limiting any overburden cement use.

When the contractor also relies on AI to analyze weather impacts and site conditions, additional low carbon concrete strategies may be incorporated, highlighting how merging technology with adaptable practices empowers teams to deliver on performance while prioritizing sustainability.

New Possibilities with Project-Specific Environmental Product Declaration
Concrete’s carbon tracking capabilities are also advancing with project-specific environmental product declarations (EPDs). These EPDs reflect real-time emissions data for specific construction sites, replacing estimates based on industry averages or as-designed projections. Incorporating detailed information such as waste volumes, transport emissions (Module A4 data) and curing impacts generates more accurate carbon accounting of each project.

For example, if a construction site reduces transport emissions by sourcing concrete produced at a closer location, this difference can be included in the project’s as-built carbon data, rather than relying on generalized approximations. Such specificity not only supports compliance with low-carbon procurement policies but also enables stakeholders to take pride in quantifiable sustainability measures.

By effectively using and sharing data, professionals can improve EPDs for greater accuracy and detail.

The implications for cost savings are considerable. By replacing or supplementing early-age cylinder testing with maturity monitors, construction teams can streamline operations and reduce associated costs like casting, transport and repeat testing due to faulty samples. Maturity monitoring also allows adjustments to mixes in real time, ensuring that concrete performance aligns with project needs without unnecessary overages in materials, which further cuts costs. Probes placed in concrete trucks serve a similar purpose, measuring critical metrics like mix uniformity, temperature and water content to confirm specifications are met, avoiding costly rework or delays.

Beyond these operational advantages, the adoption of low-carbon tools also has industry-wide safety implications by lowering the necessity for on-the-ground inspections. Automation and remote monitoring decrease physical exposure for workers. Additionally, the consistency and reliability of data increase overall project assurance and potentially reduce legal disputes over quality control. Teams can focus on optimizing project timelines and sustainability goals without sacrificing safety or quality.

Bridging the Gap
The path to net-zero concrete doesn’t end at innovation alone; it requires collaboration across sectors to adopt performance-based approaches, leverage digital tools and fully integrate carbon reduction strategies into everyday practices. By closing the gap between design and construction realities, the industry can reshape its environmental footprint while maintaining its reputation for delivering strong, durable and resilient structures.

The next step is clear. Whether it’s adopting digital technologies, partnering with local producers to achieve carbon goals or introducing adaptable specifications, the opportunity to lead on sustainability has never been greater. These strategies represent more than just incremental improvements—they are the foundation for a smarter, more sustainable future in construction.

Written by Shane Mulligan, Sustainability Market Manager, Heidelberg Materials North America. First published in the NRMCA’s Concrete InFocus magazine as "Digital Tools Help Minimize Embodied Carbon Overages,” Summer, 2025.