The team hopes this new building material could reduce heating and cooling bills while being environmentally friendly. They developed the cement mortar mix by replacing sand with silica aerogel and recycled PET plastic, which they then showed improved thermal insulation and weighs less. Recycled plastic mortar is gaining attention in the construction industry for its sustainable properties.
Thermal Testing and Benefits
Aerogels are known for their high insulation properties and are increasingly used for thermal insulation, particularly within the building sector and in aerospace. Publishing in the journal Construction and Building Materials, the team shows that the new mortar mix reduced heat loss by up to 55% compared to conventional mortar, while maintaining the required strength for masonry construction.
It also meets international standards (BS-EN 413-1:2011, ASTM C270-10, AS 1012/AS 3700), presenting an eco-friendly alternative for energy-efficient and sustainable construction. This could improve sustainable construction practices while reducing heat loss in buildings, especially in areas prone to thermal bridging, such as gaps between bricks in walls filled with mortar.
Composition and Properties of the New Recycled Plastic Mortar
Seven different formulations were tested alongside traditional mortar, with the most effective of the new mortar mixes proving to be 7% untreated silica aerogels replacing natural sand combined with 3% recycled PET (polyethylene terephthalate) plastic. The PET plastic particles used in the study came from shredded plastic bottles waste and were coarse, irregular in shape, and between 2.5-3.5 mm. The scientists washed the plastic pieces with water after shredding and left them to dry at room temperature for 24 hours.
The team analysed key properties, such as setting time, flowability (a measure to determine the workability of cement mortar), density, strength, and thermal conductivity. The new formulation helped reduce the thermal conductivity of mortar by up to 55%, compared to standard mortar samples.
Future Applications of Recycled Plastic Mortar
Study lead author, Kaniaw Marof, PhD researcher at the School of Engineering, added: “Improvement of the thermal performance of masonry buildings by reducing the energy required for heating and cooling in buildings to meet the users' comfort is one of the main topics considered in the modern construction sector. In our work, the modification of the surface of the silica aerogel particles was a crucial step towards successfully implementing silica aerogel particles within the cement binder and PET plastic.”
The scientists are aiming to test the new mix in a large-scale, real-world setting.
Next Steps for Testing and Implementation
Professor Šiller explains: “Now it is possible to reach all British standards for this new reduced thermal heat mortar with plastic and aerogels. For the next step, we wish to find collaborators, such as a construction company, to apply for funding and build the house with our ‘recipe’ for mortar. This will allow us to provide direct evidence of potential energy savings and assess the economics for masonry buildings applications.”
The use of recycled plastic mortar in construction represents a significant leap toward sustainable construction practices and reduced environmental impact. Researchers are excited to continue testing and expanding its real-world application.
