Dynamical behavior of PVA short fiber reinforced fly ash-geopolymeric extrusion composite

The polyvinyl alcohol (PVA) short fiber reinforced fly ash-geopolymer composites (SFRGC) (width to height ratio = 12.5) were firstly manufactured by the single-screw extrusion technique. The dynamic responses were studied on the SFRGC with different fiber and fly ash contents by using a Radmana impact tester. The microstructure and impact failure mechanism were also explored by laser particle size analysis (LSA)，X-ray diffraction analysis (XRD) and scanning electron microscope (SEM). The results show that PVA fiber addition greatly increases the ductility of SFRGC，especially in the case of high volume fraction of fiber，resulting in a change of impact failure mode from the brittle pattern to a ductile one. A comparative fly ash addition also exhibited obvious influence on the impact behavior. SFRGC without or with low mass fraction of fly ash (≤10%) possess high impact strength，stiffness and toughness. However，the impact resistance is greatly reduced when too much (≥30%) fly ash was incorporated. In addition，the changes in the impact response of SFRGC af ter subjecting to 20 freeze-thaw cycles and 1 month of H₂SO₄ at tack were systematically investigated.