Sustainable geopolymer composites reinforced with flax tows

摘要

In this study, we report on preparation, mechanical properties, and a microstructure of novel fly ash-based geopolymer (GP) composites that have been randomly reinforced with 0.25-1.0 wt% short-cut flax tows (FTs). It is established that if the amount of FTs in geopolymer has been increased, the flexural strength at a bend has also grown up to similar to 22%: from 4.0 MPa (unreinforced GP) to 4.9 MPa at addition of 1.0 wtWo FTs. Unlike brittle GP matrices, GP/FTs composites show a plastic character of destruction and possess higher residual bearing capacity, preserving integrity without destruction after maximum mechanical influences. At the same time, FTs addition leads to deterioration of compressive and split tensile strengths. However, these drawbacks can be minimized by FTs pretreatment and surface modification for the purpose of removal of non-cellulosic components (waxes, hemicellulose, pectin, and lignin) and increase in interfacial adhesion of a matrix to flax fibers, and also by optimization of rheological properties of geopolymer paste.