What is Nano Engineered Concrete
Concrete can be Nano-engineered concrete by the incorporation of nanosized blocks or objects (e.g., nanoparticles and nanotubes) to control material behavior and add novel properties,
or by the grafting of molecules onto cement particles, cement phases, aggregates, and additives (including nanosized additives) to provide surface functionality, which can be adjusted to promote specific interfacial interactions. https://youtu.be/ewR3Bslgyx4?si=QfynYK_gVaYuDU09
Nano Engineered Concrete is a form of concrete that contains Portland cement particles that are no greater than 100 micrometers and particles of silica no greater than 500 micrometers,
which fill voids that would otherwise occur in normal Nano-engineered concrete, thereby substantially increasing the material’s strength.
Adding ultra-fine particles to a Portland cement paste in concrete using the top-down approach of nanotechnology changes the material properties and performance by decreasing the void space between cement and aggregate in cured concrete.
This enhances strength, durability, shrinkage resistance, and adhesion to steel reinforcing bars.
Nanoparticles such as nano silica, nano clays, nano titanium oxide (TiO2), nano iron (Fe2O3), nano alumina (Al2O3), copper oxide (CuO), zinc peroxide (ZnO2) and zirconium dioxide (ZrO2) are considered for the improvement of concrete properties.
Applications of nanofibers or nanoparticles lead to high-performance (HPC), ultra-high-performance (UHPC), self-leveling (SLC), self-healing and self-compacting concrete (SCC).
MATERIALS IN NANOENGINEERED CONCRETE:
NANO SILICA In Nano Engineered Concrete:
Silica is a widely utilized nanomaterial in concrete, enhancing mechanical properties and durability by reacting with lime during cement hydration. Research indicates improved particle packing, hydration rate, strength, and reduced porosity, preventing concrete degradation.
The nano silica reacts with lime at the time of the cement hydrating procedure as well as subsequently generating a C–S–H gel, which might enhance the mechanical properties and durability of the concrete.
The cement hydration rate also was improved, which efficiently improved the strength, and lowered the dormant period and time of setting.
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CARBON NANOTUBE(CNT) In Nano Engineered Concrete:
Carbon nanotubes are added to concrete as a nanofiller due to their high surface area and unique mechanical traits and are incorporated into concrete to increase compressive strength. Composite specimens with carbon nanotubes exhibit higher
| S.NO | NANOMATERIALS USED | PROPERTY IMPROVEMENTS IN Nano Engineered Concrete: |
| 1) | Nano silica | • Contributes to reduced emissions of CO2, as the addition of 1 kg micro silica reduced almost 4 kg cement, and this can be higher if nano silica is used • Offers increased durability to concrete • Improves compressive strength • Increases the flexural strength, • Improves the tensile strength |
| 2) | Carbon nanotubes | • Decreases the concrete’s final setting time, • Restricts crack development and propagation at early ages, • Produces dense concrete, • Increased quality of bond interaction between aggregates and cement paste • Increases the compressive strength |
| 3) | Nano-TiO2 | • Increases the abrasion resistance of concrete • Improves compressive strength • Increases the durability of concrete structures • Increases the flexural strength • Speeds up the early-age hydration of ordinary Portland cement • Offers self-sensing and self-cleaning properties to concrete structures |
| 4) | Nano-Fe2O3 | • Improves compressive strength • Increases the flexural strength • Improves split tensile strength • Reduces the setting time of fresh concrete • Decreases the total porosity of concrete • Improves concrete’s abrasion resistance |
For nano concrete formation, the mixer needs to exert a mixing power ranging from 30 to 600 watts per kilogram of the mix.
This process should persist until a minimum net specific energy expenditure of 5000 joules per kilogram is achieved, with the option to raise it to 30-80 KJ per kilogram.
Following activation, a superplasticizer is introduced to the mixture and can subsequently be combined with aggregates in a standard concrete mixer.
S.NO |
NANOMATERIAL USED |
APPLICATION AREA IN CONSTRUCTION |
PROPERTIES |
| 1. | Aluminium oxide nanoparticles | Asphalt concrete, timber | Increased serviceability |
| 2. | Carbon nanotubes | Concrete | Crack prevention, mechanical durability |
| 3. | Titania nanoparticles | Concrete | Self-cleaning, increased degree of hydration |
| 4. | Silica nanoparticles | Concrete | Rapid hydration, reinforcement of mechanical strength |
| 5. | Copper nanoparticles | Steel | Formability, corrosion resistance |
| 6. | Iron oxide nanoparticles | Concrete | Abrasion-resistant, increased compressive strength |
| 7. | Clay nanoparticles | Bricks and mortar | Increased surface roughness and compressive strength concentrations. |
The admixed carbon nanotubes could also reduce the porosity of the cementitious matrix. Furthermore, CNT incorporation into concrete can result in a decrease in both the early and long-term shrinkage of Nano Engineered Concrete.
TITANIUM DIOXIDE In Nano Engineered Concrete:
Titanium dioxide inclusion in concrete imparts self-cleaning abilities through photocatalysis, leveraging the nanoparticles’ increased surface area.
Nano-TiO2 in cement matrices offers self-sensing and self-cleaning capabilities to concrete structures.
The larger surface area and stronger reactivity of the nanoparticles added into the concrete structures could improve the pozzolanic reactions, leading to a significant improvement in strength performance.
FERRIC OXIDE:
Ferric oxide nanoparticles optimally integrated into concrete boost compressive strength and improve water absorption characteristics with the inclusion of iron powder.
The synthesis involves heating Fe (CH3COO)2OH at specific temperatures with soaking times. The ferric oxide nanoparticles could increase the durability resistance of concrete against chloride, as well as sulfate anion attack.
OTHER NANO ENGINEERED CONCRETE MATERIALS
Cellulose nanomaterials, including cellulose filaments, microfibrillated cellulose, cellulose nanocrystals, and cellulose nanofibrils, enhance concrete’s elastic modulus and tensile strength with increased concentration.
The stress-free handling technique has permitted polycarboxylate to become a popular nanomaterial used in cement-based materials.
Polycarboxylate, an admixture in concrete, contributes to constructing remarkable structures like the Burj Khalifa.
Nano Engineered Concrete advantages and disadvantages
ADVANTAGES OF NANOENGINEERED CONCRETE
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- Higher strength compared to conventional concrete.
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- Fix micro-cracking.
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- Improve segregation resistance
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- Good workability because the water-cement ratio is very low.
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- Saving of cement up to 35%.
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- Nanoparticles can fill even the micro void.
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- Nanoparticles enhance the hydration process.
DISADVANTAGES OF NANOENGINEERED CONCRETE:
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- Research is in its early stages.
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- Rare availability of nanomaterials used in nano-engineered concrete.
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- Rare availability of equipment to produce Nano-engineered concrete.
Recycling using nano concrete material:
Nano silica use can enhance the recycled concrete’s microstructure. The inclusion of nano-silica in recycled aggregates could decrease the flowability and workability of pristine concrete separately, although the viscosity of recycled fresh concrete was remarkably increased.
With the usage of lower concentrations of nano silica and increasing its concentration up to 3%, the permeability and mechanical properties of recycled concretes were increased.
The concrete mix with 3% nano-silica and 40% recycled aggregate showed the optimum results for durability and strength.
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