Fiber-reinforced concrete primarily improves crack resistance under what conditions?

Fiber-reinforced concrete primarily improves crack resistance under what conditions?

• A. Only during hot weather
• B. Plastic shrinkage and drying shrinkage
• C. Only in compression
• D. Only at high temperatures

Answer: (B)

Fiber-reinforced concrete improves crack resistance by bridging cracks and carrying tensile loads across them, which slows crack growth and reduces crack widths. This is most effective for cracks caused by restrained shrinkage—specifically plastic shrinkage that happens soon after placement and drying shrinkage that occurs as the concrete loses moisture during curing. In these cases, cracks form when the concrete experiences tensile stresses, and the fibers help arrest those cracks and keep them narrower, improving durability and permeability resistance. The benefit isn’t limited to hot weather or high temperatures, nor is it confined to compression scenarios; shrinkage cracks driven by evaporation and moisture loss are the situations where fiber reinforcement provides the most noticeable improvement.

Fiber-reinforced concrete improves crack resistance by bridging cracks and carrying tensile loads across them, which slows crack growth and reduces crack widths. This is most effective for cracks caused by restrained shrinkage—specifically plastic shrinkage that happens soon after placement and drying shrinkage that occurs as the concrete loses moisture during curing. In these cases, cracks form when the concrete experiences tensile stresses, and the fibers help arrest those cracks and keep them narrower, improving durability and permeability resistance. The benefit isn’t limited to hot weather or high temperatures, nor is it confined to compression scenarios; shrinkage cracks driven by evaporation and moisture loss are the situations where fiber reinforcement provides the most noticeable improvement.