Final answer:
Engineered cementitious composites (ECC) do not contain gravel but instead contain fly ash. ECC is a ductile and crack-resistant material that incorporates fibers and nanoparticles.
Step-by-step explanation:
Unlike traditional concrete, engineered cementitious composites (ECC) do not contain gravel but instead contain fly ash.
ECC is a type of advanced cement-based material that is designed to be highly ductile and crack-resistant. It achieves these properties by incorporating fibers and nanoparticles into the cement matrix.
Fly ash is a byproduct of coal combustion and is often used as a supplementary cementitious material in concrete. It acts as a filler, improving the workability and durability of the ECC.