A study published in Structural Concrete highlights the potential of cellular lightweight concrete (CLC) as a more sustainable alternative for structural shear walls (SW) in earthquake-prone areas. The researchers conducted a "cradle-to-gate" life cycle assessment (LCA) to measure the environmental impact of constructing a seven-story residential building using CLC in Quito, Ecuador.
Study: Cellular concrete: A viable low‐carbon alternative for developing countries in seismic regions? Image Credit: Andrey Mihaylov/Shutterstock.com
Key Findings
CLC, known for its lightweight properties and superior insulation, offers significant environmental advantages over traditional concrete. By incorporating a foaming agent, it reduces density while maintaining structural integrity. The study found that CLC can cut CO2 emissions by 15 %–28 % compared to conventional concrete, making it a promising solution for reducing the carbon footprint of buildings. Despite its advantages, little research has been done on its seismic performance, particularly in high-risk earthquake zones.
This study aimed to fill that gap by integrating LCA with seismic performance analysis to evaluate whether CLC could be effectively used for SW systems in multi-story buildings in earthquake-prone areas.
Research Methods
The researchers analyzed the structural and environmental impact of a seven-floor residential building in Quito, covering a total floor area of 255.44 m2. The SW design considered multiple factors, including aspect ratio, flexural-compression performance, shear resistance, and coupling beam design. The mechanical properties of CLC followed standard guidelines, adhering to Ecuador's National Building Code and the American Concrete Institute’s standards.
Seismic parameters were carefully evaluated through a linear dynamic analysis, incorporating a modal response spectrum analysis aligned with the Ecuadorian Construction Code. The study also considered site-specific seismic risks to understand the structure's response to dynamic forces.
For the LCA, researchers focused on emissions from material production, transportation, and construction. Key materials analyzed included premixed cellular concrete, reinforcement steel, and wood-steel formwork. Excavation, backfill, and surplus foundation materials were also factored in. To maintain focus on the most significant sources of carbon emissions, aspects such as labor and auxiliary materials were excluded.
Environmental and Structural Impact
The study found that material manufacturing and construction phases accounted for the most significant environmental impacts. Specifically:
- CLC production contributed 40 % of total CO2 emissions and 43 % of total energy consumption.
- Reinforcement steel production had an even larger footprint, making up 58 % of CO2 emissions and 53 % of total energy use.
- Combined, concrete and steel production were responsible for nearly 98 % of emissions and energy consumption.
The high environmental impact was attributed to energy-intensive raw material extraction and processing. During construction, slab casting with CLC and reinforcement steel had the most significant environmental footprint due to material demand. Walls, coupling beams, and earth-moving activities like excavation and backfilling had minor contributions, accounting for 0.2 % to 0.8 % of total CO2 emissions and energy use.
Structurally, the study confirmed that a 20 cm-thick CLC SW system performed well under seismic conditions. Under combined loading, the system exhibited inelastic drifts of 0.002 and 0.003 in the X and Y directions, respectively—well within Quito’s serviceability and ultimate limit state requirements. The results indicate that CLC can maintain stiffness and integrity even in earthquake-prone settings.
The Bottom Line
This research underscores the potential of CLC as a viable, sustainable alternative to traditional concrete in seismic zones. The findings show that CLC-based SW systems can reduce carbon emissions and energy consumption while maintaining essential structural integrity for earthquake resistance.
The cradle-to-gate LCA provides valuable data for engineers and policymakers, supporting more environmentally conscious building designs. As the industry continues shifting toward eco-friendly solutions, CLC presents a strong case for reducing the environmental impact of urban development in high-seismic areas.
Journal Reference
Coral, E., Ávila, C., Gallegos, E., Salazar, A., Barros, L., & Rivera, E. (2025). Cellular concrete: A viable low‐carbon alternative for developing countries in seismic regions? Structural Concrete. DOI: 10.1002/suco.202400892, https://onlinelibrary.wiley.com/doi/10.1002/suco.202400892
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