Impact resistance of geopolymer concrete under different types of fiber admixtures

To investigate the dynamic mechanical response characteristics of geopolymer concrete under impact load, the effects of different curing ages and strain rates on the impact resistance of geopolymer concrete have been explored. First, this paper first obtains the optimal mix ratio of geopolymer concrete by optimizing the slump test of mix ratio. Second, the stress–strain constitutive relationship of geopolymer concrete at different ages is deduced, and the mechanical properties, such as axial compressive strength and elastic modulus, are determined. Finally, two different kinds of fibers, carbon fiber and steel fiber, are mixed into concrete, which are utilized to test the mechanical properties including compressive strength, splitting tensile strength, flexural strength, and impact toughness. The results indicate that with the increase in carbon fiber content, the compressive strength, splitting tensile strength, and flexural strength of geopolymer concrete decrease first and then increase. Moreover, with the increase in steel fiber content, the compressive strength of geopolymer concrete increases continuously, the splitting tensile strength increases first and then decreases, the flexural strength decreases first and then increases, and the impact toughness increases first and then decreases.