Experimental Study On Durability Of Ultra-high Toughness Slag And Fly Ash Base Geopolymer Composite

Geopolymer is a green and environmentally friendly building material,which can effectively utilize industrial waste(fly ash and slag),has almost no CO2 emissions during the production process,and has the characteristics of fast hardening,early strength and excellent durability.Wide range of applications.Ultra High Toughness Slag and Fly Ash Base Geopolymer Composite is based on slag,fly ash and solid sodium silicate as raw materials,mixed with an appropriate amount of polyethylene(PE)fiber for short,not only improves the brittleness of geopolymers,but also has ultra-high strength and ductility.All buildings are unavoidable carbonization hazards,and my country’s vast coastline,hydraulic buildings will be eroded by chloride ions,resulting in reduced structural durability and damage.Therefore,by changing the dosage of fly ash,water-binder ratio,the dosage of alkali activator and f Fiber volume content,etc.,the chloride ion corrosion resistance and carbonization resistance of ultrahigh toughness slag/fly ash-based geopolymer composites were studied.The compressive strength and tensile properties before and after erosion were compared,and the effects of chloride ion erosion and carbonization on the mechanical properties of geopolymer composites were obtained.Finally,the phase composition and pore structure were tested,and the geopolymer composites were obtained.Mechanism of action against chloride attack and carbonation.The main conclusions are as follows:(1)The dosage of fly ash has a significant effect on the compressive strength of EGC.When the dosage of fly ash is 0%,the compressive strength reaches 78.65MPa;when the water-binder ratio is 0.32 and the dosage of alkali activator is 6%,the compressive strength is respectively are 77.56MPa and 82.09MPa;all the EGC ratios in this test show obvious strain hardening characteristics,and the EGC with a fly ash content of 40%has an ultra-high strain,reaching 8.15%.(2)Chloride ion erosion will cause the compressive strength of EGC to decrease.With the decrease of fly ash content and water-binder ratio,the resistance to chloride ion penetration increases,and the loss rate of compressive strength also decreases gradually;the alkali activator content is 6%And when the fiber volume content is 2.0%,the resistance to chloride ion penetration is strong,and the compressive strength loss rate is small,but the alkali activator content and fiber volume content too much or too little will reduce the resistance to chloride ion penetration and increase the strength loss;Except for the alkali activator content of 6%and 7%,the ultimate tensile strength increased and the ultimate tensile strain decreased after 90 days of chloride ion attack.The remaining EGC ratios showed a decrease in ultimate tensile strength after chloride ion attack.and ultimate tensile strain slightly increased;the greater the chloride ion concentration,the greater the negative impact on the mechanical properties of EGC.(3)Carbonization reduces the compressive strength of EGC with different ratios.With the decrease of fly ash content and water-binder ratio,the carbonization rate decreases,and the compressive strength loss rate also decreases;the dosage of alkali activator is 6%and fiber volume content of 2.0%,the carbonization rate is small,and the compressive strength loss rate is also small,but the alkali activator content and fiber volume content too much or too little will increase the carbonization rate and the loss rate of compressive strength.except that the ultimate tensile strain of EGC with fly ash content of 0%and 20%increased and the ultimate tensile strength decreased after carbonization for 28 days,the ultimate tensile strength and The ultimate tensile strain is reduced;the compressive strength and tensile properties of EGC are enhanced when the concentration of CO2 is 5%.(4)Due to the existence of hydrotalcite,the reaction product of slag-based EGC can effectively adsorb chloride ions and CO2,and the porosity is small,so the strength and resistance to chloride ion corrosion and carbonization are good,and no detection was detected after mixing with fly ash.The existence of hydrotalcite,but the emergence of N-A-S-H gel;the water-to-binder ratio mainly affects the strength and durability through the generation of hydration products and pore structure;when the alkali activator content is 6%,the degree of reaction is higher,so the hydration products With more content,the porosity is also smaller,so the strength and corrosion resistance are better;when the fiber volume content is appropriate(2.0%),the pore structure of the matrix is denser,so the corrosion resistance is stronger.