Macro and Mesoscopic Study on the Mechanical Properties of Metakaolin-based Geopolymer Reinforced by Fine Sand

Abstract

In order to improve the mechanical properties of geopolymer, experimental comparison groups (a) to (f) were set up to explore the influence of particle size and content of fine sand on the unconfined compressive strength of metakaolin-based geopolymers. The results showed that when the particle size of the fine sand decreased, the strength of the geopolymer increased more significantly. When the particle size of the fine sand was less than 0.15 mm and the content was 10% of the maximum mass fraction, the composite possessed the highest strength and reached 41.51 Mpa. The effect of fine sand content on the polymerization process was characterized by SEM. The particle flow software PFC3D was selected to simulate the unconfined compressive process of the specimens, and Fish functions were established to monitor the quantity of cracks, crack distribution status, particle failure mode and porosity changes of the specimens during the unconfined compressive test experiment. The effect of fine sand with different particle sizes and contents on the compressive strength of metakaolin-based geopolymer was revealed from the viewpoint of mesomechanics.