Researchers at the University of Portsmouth have been investigating how agricultural waste fibers could play a role in the future of sustainable construction. Their latest study suggests that incorporating jute fibers into raw earth mortar strengthens the material, reduces cracking, and potentially lowers the need for cement in construction mixes. The findings form part of a wider movement in civil engineering to create affordable, low-carbon alternatives to conventional building materials.
Dr. Muhammad Ali, Associate Professor in Materials and Environmental Innovation at Portsmouth, explained that research into compressed earth blocks has been extensive, but less attention has been paid to the mortar that holds them together. Improving mortar performance, he said, is essential for developing low-cost, environmentally responsible building solutions. His team’s work aligns with global sustainability targets, particularly the UN’s goals for affordable and safe housing by 2030.
Cottrell, J. A., Ali, M., Tatari, A., & Brett Martinson, D. (2025). Influence of jute fibre and cement on the mechanical properties of raw earth mortar. Journal of Building Engineering, 108, 112935. https://doi.org/10.1016/j.jobe.2025.112935
Raw earth mortar, a mix of clay, silt, sand, and water, is commonly used to bind compressed earth blocks in regions where locally available materials are often the most practical and affordable option. Unlike cement, which requires energy-intensive production processes, earth mortars have a much lower environmental impact and are compatible with sustainable building practices. However, their mechanical properties are often limited, which can reduce the lifespan and structural resilience of the buildings they support.
Dr. Muhammad Ali, Professor at Portsmouth University stated,
“Through this research we have been able to identify potential improvements for raw earth mortar to help further develop low-cost and environmentally friendly building materials around the world and support the creation of sustainable communities.”
The Portsmouth team focused on whether plant fibers could bridge that gap. They tested three mortar formulations, comparing traditional stabilized mixes with those that included 20-millimeter jute fibers, added at a fraction of the soil’s weight. Laboratory tests showed measurable improvements: compressive strength rose by roughly twelve percent, while flexural strength increased by around twenty percent. The presence of fibers also helped to control shrinkage and minimize micro-cracking, both of which are persistent issues in earthen construction. These results suggest that small additions of natural fibers can enhance performance without the carbon cost associated with cement.
The study does not stand in isolation. Around the world, researchers have been experimenting with natural fibers such as hemp, sisal, and waste wood to improve mortars and concretes. Some studies have shown that hemp fibers combined with recycled brick powder can optimize mechanical behavior, while others have reported that waste plastic fibers can improve ductility and crack resistance in concrete. Collectively, these projects reflect a growing interest in using materials that are both renewable and locally available, reducing reliance on industrial cement.
The promise of fiber-reinforced mortars is clear, but several questions remain. Natural fibers are vulnerable to moisture, biological decay, and alkaline environments, all of which can shorten their effective lifespan. Ensuring consistent mixing at the construction scale, as opposed to controlled laboratory conditions, will also be a challenge. Furthermore, building codes and standards have not yet fully adapted to account for these types of materials, meaning further validation and regulatory integration will be necessary before widespread adoption can occur.
Despite these hurdles, the broader implications are encouraging. For communities in low-income regions, where cost and access to materials are often the largest barriers to safe housing, innovations like fiber-reinforced earth mortar could improve both affordability and durability. For wealthier nations, the attraction lies in lowering the carbon footprint of construction, which remains one of the world’s most energy-intensive industries.
The Portsmouth findings contribute to a steady progression of research that merges traditional practices with modern engineering science. Rather than presenting a single breakthrough, the work represents a practical step forward, showing how waste streams can be transformed into valuable resources for sustainable construction. For engineers and material scientists, it reinforces the idea that future building technologies may not always come from advanced synthetics, but from revisiting simple, abundant, and often overlooked natural materials.
Adrian graduated with a Masters Degree (1st Class Honours) in Chemical Engineering from Chester University along with Harris. His master’s research aimed to develop a standardadised clean water oxygenation transfer procedure to test bubble diffusers that are currently used in the wastewater industry commercial market. He has also undergone placments in both US and China primarely focused within the R&D department and is an associate member of the Institute of Chemical Engineers (IChemE).
