Study On Performance Of Metakaolin Slag-based Geopolymer Reinforced Toughness By Organic Resin

The developments of geopolymers and toughening techniques of geopolymers are systematically reviewed in the thesis. The existing problems in geopolymer materials are comprehensively analyzed and a new idea about improved toughness of geopolymer materials is proposed. A new type of metakaolin slag-based geopolymer composite reinforced toughness by a mixture of butyl acrylate and acrylic acid copolymer and ethylene-vinyl acetate copolymer are prepared. The mechanical properties, mechanism of reinforced toughness, high temperature resistance, seawater corrosion resistance for the geopolymer materials are explored by using of X-ray diffraction (XRD), scanning electron microscope (SEM), thermal gravimetric analysis/differential scanning calorimetry (TGA/DSC), X-ray fluorescence (XRF),and some valuable results are obtained.The results of mechanical properties show that as compared with the sample without resin (0 wt%), the compressive strength of the sample with doping content of 1 wt% resin increases by 8.4MPa and the flexural strength increases by 2.5MPa in the curing age of 28d, respectively. The SEM results indicate that the compact degrees of geopolymer are modified and the microcrack is reduced by doping organic resin. The study of hydration heat exhibits that the hydration rate of alkali-activated metakaolin slag slag-based geopolymer is accelerated leading to an increase of early hydration heat by doping resin. A toughening mechanism reinforced by organic resin is suggested in combination with the characterization results of TGA/DSC, SEM hydration heat and so on. The polar groups of chain-like organic resin have a stabilizing effect on water molecules by adsorption of H2O to form hydrogen bonds and inhibit the evaporation of water so as to benefit the geopolymerization progress. In addition, the resin combines with geopolymer to form chemical bonds and incorporates into interstices of geopolymer to increase the percentage of micropore, reduce the average pore size, increase bulk density, prevent the cracking growth and increase the fracture toughness.The high temperature resistance results demonstrate that the metakaolin slag-based geopolymer can maintain higher compressive strength at moderate calcinations temperature, whereas the compressive strength sharply decreases calcinated at 850℃for 1h. The investigation results reveal that the metakaolin slag-based geopolymer composite has ability of seawater corrosion resistance.