1 - Introduction to fiber-reinforced alkali-activated composites

Abstract

Fiber utilization in composite materials becomes significant, especially for ductility requirements for the structures. Recently, alkali-activated materials or composites have emerged as alternative cement-free construction materials to reduce CO2 emission and adverse effects of Ordinary Portland Cement (OPC) production. Similar to OPC, alkali-activated composites perform a brittle behavior due to their low tensile strength. Therefore different fibers are incorporated to obtain superior tensile and flexural performances depending on fiber material type, length, shape, aspect ratio, and volume ratio. In general, fibers can be classified as metallic (steel) fibers, carbon fibers, polymeric (synthetic, natural, and inorganic) fibers, and hybrid fibers. Fibers enhance most of the significant physical, mechanical, and durability performances, such as splitting tensile strength, flexural strength, ductility, flexural toughness, bond resistance, impact resistance, chloride permeability, corrosion resistance, and chemical resistance. The degree of enhancements depends on the fiber type, fiber strength, fiber property, fiber shape, fiber length, fiber volume, fiber aspect ratio, fiber distribution, and fiber orientation density. In this chapter, the enhancements in mechanical strength and durability performance have been comprehensively evaluated for different fibers.