Effect of Polypropylene Fiber Addition to Bottom Layer on the Mechanical Properties of Functionally Graded Concrete Containing Fly Ash

Abstract

AbstractThe present study focuses on effect of polypropylene (PP) fiber addition to bottom layer on the mechanical properties of functionally graded concrete (FGC) containing fly ash (Fa). The FGC specimens were prepared with two concrete layers having the same thickness. The top layer of FGC specimens was composed of normal concrete or Fa concrete without PP fiber, whereas the bottom layer was made from normal concrete, Fa concrete, or Fa concrete with 0.3% PP fiber. A constant water-to-cementitious materials ratio of 0.36 was applied for all mixtures. Fly ash was used to partially replace ordinary Portland cement by the proportion of 20% (by mass). The results showed that the flexural strength and impact resistance were significantly increased at the age of 28 days, whereas the compressive strength was slightly enhanced due to the PP fiber addition to the bottom concrete layer of FGC specimens. Functionally graded concrete using normal concrete in a top layer and Fa concrete reinforced with PP fiber in a bottom layer was an optimal material considering not only effectively economic aspect but also beneficial mechanical properties in terms of compressive strength, flexural strength, and impact resistance up to the age of 28 days.KeywordsFunctionally graded concreteCompressive strengthFlexural strengthImpact resistancePolypropylene fiber