44 2 Carbon Fibers and Nanofillers Air Filler b Figure 2.8.Interfadial microstructures for:a a conformable interfacial filler;b a nonconformable interfacial filler 8 ocfo b Figure 2.9.Schematic illustration of carbon black structures.a High structure(with a large aggregate size).b Medium structure(with a medium aggregate size).cLow structure(with a small aggregate size) Figure 2.10.The distribution of discontinuous fibers in a composite.a Nonuniform distribution due to fiber clumping.b Uniform distribution in the absence of clumping Due to the small thicknesses of composite interfaces,nanofillers are useful for interface modification.For example,silica fume(nanoparticles around 0.1 um in size)added to a concrete mix aids bonding between the concrete and steel rebars,44 2 Carbon Fibers and Nanofillers Figure 2.8. Interfacial microstructures for: a a conformable interfacial filler; b a nonconformable interfacial filler Figure 2.9. Schematic illustration of carbon black structures. a High structure (with a large aggregate size). b Medium structure (with a medium aggregate size). c Low structure (with a small aggregate size) Figure 2.10. The distribution of discontinuous fibers in a composite. a Nonuniform distribution due to fiber clumping. b Uniform distribution in the absence of clumping Due to the small thicknesses of composite interfaces, nanofillers are useful for interface modification. For example, silica fume (nanoparticles around 0.1μm in size) added to a concrete mix aids bonding between the concrete and steel rebars