:Graphene is a two-dimensional nanomaterial consisting of a single layer of carbon atoms arranged in a hexagonal lattice. It comes in different forms, including:

• Monolayer Graphene (1–3 atomic layers)

  • Particle size: 1–10 nm thickness, lateral size 500 nm–10 µm

  • Applications: Advanced coatings, self-sensing concrete

• Few-Layer Graphene (FLG) (3–10 atomic layers)

  • Particle size: 5–50 nm thickness, lateral size 1–10 µm

  • Applications: Structural reinforcement, crack resistance

• Graphene Nanoplatelets (GNPs) (Multi-layered stacks)

  • Particle size: 50–100 nm thickness, lateral size 10–100 µm

  • Applications: Enhanced flexural strength, conductivity, and durability

A. Processing Methods for Graphene Production

Graphene can be produced using top-down exfoliation methods from graphite or bottom-up synthesis from carbon precursors. The production method influences graphene’s purity, dispersion, and effectiveness in concrete applications.

Top-Down Methods (Exfoliation-Based)

1. Liquid-Phase Exfoliation (LPE)

   • High-shear forces break down graphite into graphene sheets in a liquid medium.

   • Produces graphene nanoplatelets (GNPs) suitable for bulk cement applications.

2. Electrochemical Exfoliation

   • Electrolytic processing separates graphene layers from graphite.

   • Generates few-layer graphene (FLG) with controlled thickness for high-strength applications.

3. Graphite Oxidation & Reduction (GO/rGO)

   • Graphite is chemically oxidized into graphene oxide (GO), then reduced back to reduced graphene oxide (rGO).

   • Enhances hydration reactions in cement through functionalized surface chemistry.

Bottom-Up Methods (Synthetic Growth)

1. Chemical Vapor Deposition (CVD)

   • Grows monolayer graphene on metal substrates from carbon-containing gases.

   • Produces high-purity graphene, but with high cost—better suited for coatings rather than bulk concrete.

B. Applications of Graphene in Cementitious Systems

Graphene can significantly improve mechanical, thermal, and electrical properties when incorporated into concrete at very low dosages (typically 0.02–0.10% by cement weight).

A. Strength & Durability Enhancement

• Increases compressive strength by 30–50% due to nano-reinforcement effects.

• Reduces shrinkage cracking, improving flexural strength.

B. Improved Hydration & Microstructure

• Graphene oxide (GO) accelerates C-S-H formation, leading to denser cement paste.

• Enhances chemical bonding with cement particles, improving long-term durability.

C. Smart & Functional Concrete

• Graphene’s electrical conductivity enables self-sensing concrete that detects stress and strain.

• Can be used for self-heating concrete in cold climates.

D. Sustainability & Carbon Footprint Reduction

 

• Graphene-enhanced concrete requires less cement for the same strength, reducing CO₂ emissions.

• Can be synthesized from recycled carbon sources, making it a sustainable additive.

• h, reducing CO₂ emissions.

• Can be synthesized from recycled carbon sources, making it a sustainable additive.

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