Ozone Applications
Concrete
Influence of Water with Oxygen and Ozone Micro-Nano Bubbles on Concrete Physical Properties
Author: Małgorzata Grzegorczyk-Fra´nczak, Danuta Barnat-Hunek, Kalina Materak and Grzegorz Łagód
Abstract
Concrete is the backbone of modern infrastructure, but its exposure to harsh environmental conditions—freezing temperatures, salt, moisture, and chemical attack—can lead to gradual degradation. Recent research has highlighted an exciting innovation: using water infused with oxygen (O₂) and ozone (O₃) micro-nano bubbles (MNBs) in concrete production. The results are nothing short of transformative, promising stronger, more durable, and environmentally friendly concrete.
What Are Micro-Nano Bubbles (MNBs)?:
Micro-nano bubbles are gas bubbles with diameters ranging from a few nanometers to a few micrometers. Their unique properties make them powerful tools in enhancing material performance:
- High Stability: These bubbles remain suspended in liquid for extended periods without bursting.
- Reactive Nature: They can generate free radicals, which react with surrounding materials.
- Surface Tension and Negative Zeta Potential: These properties help MNBs penetrate and interact with material structures at the microscopic level.
Traditionally used in industries like water treatment and medicine, MNB technology has now entered the realm of construction, with significant implications for concrete production.
The Experiment: MNBs in Concrete:
Researchers tested the effects of substituting regular tap water with MNB-infused water in concrete mixes. Three types of concrete were prepared:
- Reference concrete (REF): Made with ordinary tap water.
- O₂ concrete: Made with water infused with oxygen MNBs.
- O₃ concrete: Made with water infused with ozone MNBs.
Each mix had the same water-to-cement ratio (0.35) and used Portland cement CEM I 42.5R, quartz sand, and gravel aggregates.
Key Findings and Analysis:
Improved Physical Properties
Water Absorption:
- O₃ concrete showed a 52.3% reduction in water absorption coefficient compared to the reference mix.
- O₂ concrete achieved a 42.7% reduction.
- Lower water absorption limits moisture ingress, reducing freeze-thaw damage and improving long-term durability.
Porosity:
- O₃ and O₂ concretes exhibited lower total and open porosity compared to the reference concrete. Total porosity decreased by 6–7%, and open porosity reduced by 9.76% for O₃ concrete and 9.87% for O₂ concrete.
- Reduced porosity creates a denser matrix, better resisting environmental stressors.
Superior Mechanical Performance
Compressive Strength:
- O₃ concrete demonstrated a remarkable 61% increase in compressive strength after 28 days, elevating it from a strength class of C20/25 to C35/45.
- O₂ concrete also showed a modest strength improvement, with compressive strength increasing by 5%.
- Flexural Strength:
- O₃ concrete exhibited a 5% improvement in flexural strength, while O₂ concrete showed no significant change compared to the reference.
Enhanced Durability
Frost Resistance:
- O₃ concrete displayed 2.4 times greater frost resistance after 150 freeze-thaw cycles, with only a 7.8% loss in compressive strength. By contrast, the reference concrete lost 18.5% strength under the same conditions.
- Weight loss during freeze-thaw tests was significantly lower for O₃ and O₂ concretes, further confirming their improved frost resistance.
Resistance to Salt Crystallization:
- O₃ concrete exhibited better performance in salt crystallization tests, showing the smallest weight change (2.11%) compared to O₂ concrete (2.21%) and the reference (2.37%).
Mechanisms Behind the Improvements:
The introduction of MNBs creates significant microstructural changes in concrete:
Bubble Dispersion:
- MNBs improve the homogeneity of the cement mix by reducing capillary pores and creating a denser cement matrix.
- The small size and negative charge of MNBs help them penetrate cement particles more effectively, enhancing hydration and reducing voids.
Hydration Reaction Enhancement:
- MNBs facilitate faster and more complete hydration of cement particles. The additional contact between bubbles and cement particles results in a stronger bond and denser structure.
Durability Under Environmental Stress:
- The ability of MNBs to disrupt large pores and reduce water absorption directly contributes to the material's resilience under freezing, thawing, and salt exposure.
Why This Matters:
The use of oxygen and ozone MNBs addresses long-standing challenges in concrete technology:
Eco-Friendly Construction:
- Unlike traditional chemical air-entraining agents, MNBs are non-reactive and environmentally benign. They provide a sustainable alternative to harmful chemical additives.
Improved Performance:
- Increased strength and durability extend the service life of concrete structures, reducing maintenance costs and resource consumption.
Broad Applications:
- This innovation holds potential for infrastructure in harsh climates, marine environments, and regions exposed to frequent freeze-thaw cycles.
Applications and Future Directions:
The promising results from this research open doors to a variety of applications:
- Cold-Climate Infrastructure: Roads, bridges, and buildings exposed to frost and snow.
- Marine Construction: Improved salt resistance makes this concrete ideal for piers, docks, and coastal structures.
- Eco-Friendly Projects: Builders aiming to reduce chemical usage can leverage MNBs for green construction.
Future research could explore the long-term effects of MNBs on concrete in real-world conditions, as well as their compatibility with other construction materials.
The integration of oxygen and ozone micro-nano bubbles in concrete production represents a significant leap forward. By improving strength, durability, and environmental compatibility, this innovation sets a new standard for construction materials. As the industry continues to evolve, MNB technology could become a cornerstone of sustainable and high-performance construction.
Ozone treatment on the dispersion of carbon nanotubes in ultra-high performance concrete
Author: Myungjun Junga,Sung-gulHonga, Juhyuk Moon
Abstract
The field of construction materials is being transformed by nanotechnology, and one exciting development is the integration of carbon nanotubes (CNTs) into ultra-high performance concrete (UHPC). Known for their extraordinary mechanical and electrical properties, CNTs have the potential to revolutionize concrete technology. However, achieving uniform dispersion of CNTs in the cement matrix has been a persistent challenge—until now. A recent study introduces ozone treatment as a groundbreaking solution to enhance CNT dispersion and improve UHPC properties.
Why Dispersion Matters:
Carbon nanotubes, while promising, present a major obstacle: they tend to cluster together due to their high aspect ratio, surface area, and van der Waals forces. Without proper dispersion, CNTs form aggregates that act as weaknesses in the concrete, reducing strength and performance.
Traditional dispersion methods, such as sonication with surfactants, often damage the CNTs or introduce air bubbles that degrade the concrete’s mechanical properties. Ozone treatment, however, offers a cleaner, more effective alternative.
The Role of Ozone Treatment:
Ozone treatment works by attaching oxygenic and carboxylic chemical groups to the surface of CNTs. This functionalization enhances their steric repulsion, preventing clumping and promoting uniform distribution in both aqueous suspensions and the solid UHPC matrix. Here’s how it works:
- Enhanced Chemical Interactions: Ozone oxidizes the CNT surface, enabling it to interact better with cementitious materials.
- Improved Stability: Treated CNTs remain suspended longer, avoiding sedimentation during mixing.
- Steric Repulsion: Negatively charged groups on the CNT surface repel each other, ensuring even dispersion.
Experimental Setup:
The study compared four sample types:
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Plain UHPC with no CNTs (Control)
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UHPC with untreated CNTs (CNT0.1-P)
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UHPC with ozone-treated CNTs (CNT0.1-O3)
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UHPC with ozone-treated water but no CNTs (CNT0-O3)
Key processes included:
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Ozone treatment at 0.1 ppm for CNT suspension.
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Spatially-resolved small-angle X-ray scattering (SAXS) to evaluate dispersion.
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Calorimetry, X-ray diffraction (XRD), and thermogravimetric analysis (TGA) to assess hydration and material properties.
Game-Changing Results:
Superior Dispersion:
- Ozone-treated CNTs achieved a 77.1% reduction in particle size compared to untreated CNTs.
- SAXS analysis confirmed uniform dispersion across the UHPC matrix, critical for optimal performance.
Enhanced Flowability:
- Ozone-treated CNTs increased the fluidity of UHPC, countering the typical flow reduction caused by CNTs. This was attributed to a "double steric repulsion effect" between CNTs and cement grains.
Accelerated Hydration:
- Treated CNTs acted as nucleation sites, accelerating hydration reactions at early stages. This led to quicker formation of calcium-silicate-hydrate (C-S-H) gels, a key component in concrete strength.
Improved Compressive Strength:
- UHPC with ozone-treated CNTs (CNT0.1-O3) exhibited a 30.6% increase in compressive strength after one day and a 9.8% increase after 28 days compared to plain UHPC.
Dense Microstructure:
- Ozone treatment produced a denser, more cohesive matrix by anchoring CNTs within the cement hydration products.
Implications for the Future:
Ozone-treated CNTs offer a scalable, eco-friendly way to enhance UHPC. This innovation holds promise for applications requiring ultra-durable materials, including:
- High-performance infrastructure in extreme climates.
- Lightweight yet strong components for aerospace and automotive industries.
- Smart concrete with electromagnetic shielding or self-sensing capabilities.
The incorporation of ozone-treated CNTs into UHPC marks a significant advance in construction nanotechnology. By solving the long-standing problem of CNT dispersion, this technique unlocks the full potential of CNTs to create stronger, more durable, and sustainable concrete for the challenges of tomorrow.