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New concrete based on zeolite and chitosan reduces dependence on Portland cement, gains antibacterial action and targets use in panels, tiles and coatings in sustainable construction
A new clean concrete made with shrimp shell waste has been developed by researchers from the Higher Polytechnic School of the Coast, in collaboration with the University of Buenos Aires, to reinforce a geopolymer and improve performance in non-structural applications. The material combines natural zeolite from Ecuador with chitosan, a biopolymer extracted from chitin present in shells, and has been tested for mechanical and microbiological properties.
The work was presented as a highlight of an article on April 13, 2026, and describes laboratory tests with low concentrations of chitosan, evaluating compressive strength, microstructure, and antibacterial activity, focusing on sustainable construction solutions and circular economy.
Why “clean concrete” became a target in sustainable construction
The research starts from an environmental diagnosis: the construction industry accounts for approximately 7% to 8% of global carbon dioxide emissions, with a significant contribution from Portland cement production. In this scenario, traditional concrete faces pressure for lower carbon footprint alternatives.
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A giant printer spits concrete layer by layer and builds an entire house in less than 24 hours — in the United States, 100 families already live in houses made this way and pay up to 20% less on their energy bills.
Geopolymers emerge as a viable route because they can be produced by alkaline activation of natural aluminosilicates and deliver comparable mechanical properties in non-structural uses.
The proposal of the study is to transform this path into a more sustainable concrete, with biological reinforcement and reuse of waste.
From shrimp shell to geopolymer reinforcement
The new concrete uses chitosan, a natural polymer derived from chitin, recognized for its biodegradability and antibacterial potential.
In the study, chitosan was obtained through a controlled chemical process from waste from the shrimp industry, connecting the material to the logic of reusing by-products.
The researchers incorporated very low concentrations of chitosan, between 0.075% and 0.20% by weight, into geopolymeric matrices made from natural zeolite from the coastal region of Ecuador. They then analyzed the structural, thermal, microstructural, and microbiological properties of the resulting concrete.
Strength increases up to 67%, but the concrete is for non-structural use
The results showed that the addition of chitosan increased the compressive strength by up to 67%, rising from 2.10 MPa in the base material to maximum values close to 3.51 MPa in optimized formulations.
The authors emphasize that these resistances do not compare to those of conventional structural concrete, but are suitable for applications such as panels, coatings, tiles, and non-structural architectural elements, where mechanical gain can mean greater durability and performance in service.
Antibacterial concrete targets high-contact surfaces
In addition to mechanical gain, the study points out a health and urban use differential. The reinforced geopolymers showed significant antibacterial activity against Klebsiella aerogenes and Staphylococcus aureus, bacteria associated with hospital infections and contamination of surfaces in urban and industrial environments.
This type of concrete with intrinsic protection opens up opportunities for applications in places where microbial load is a constant concern, such as hospitals, schools, commercial kitchens, and public areas with heavy traffic.
Microstructure explains performance and defines an “ideal” mixing range
Microscopic analyses indicated that chitosan alters the internal microstructure of the material, helping to increase the cohesion of the inorganic matrix when used in moderate amounts. In excessive concentrations, however, clusters may arise, which partially reduces mechanical efficiency.
This behavior allowed for the identification of a formulation range considered more efficient, reinforcing that clean concrete depends on a balance in the mix to deliver performance without losses.
Circular economy and adaptation potential in Latin America
The work is also presented as an example of convergence between materials engineering, waste recovery, and sustainability.
The use of local natural zeolites reduces dependence on imported raw materials, while the reuse of shrimp waste decreases the environmental impact of the fishing chain.
The authors highlight that clean concrete can be adapted to Latin American contexts, as it relies on abundant natural resources and manufacturing processes described as relatively simple, with potential for integration into national sustainable construction strategies.
Would you use clean concrete with shrimp shell waste in tiles, panels, or coatings for your home if it were more durable and also had antibacterial action?
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