Optimization of mechanical property and sensing performance in CNF/fly ash-based geopolymer composites
Fly ash based geopolymer composites with varied CNF mass fractions(0-2.0%)were prepared by adding carbon nanofiber(CNF)to the fly ash based geopolymer via physical mixing method.The microstructure,mechanical property,electrical property and sensing property of the fly ash based geopolymer composites were investigated to reveal the specific effect of CNF mass fraction on the mechanical and sensing properties of this fabricated geopolymer composites,and the composites with CNF mass fraction of 0.5%underwent stability testing,which included a quantitative analysis of their variance stability.The results show that the elastic modulus and flexural strength of the composites increase significantly with the increase of CNF mass fraction.When the CNF mass fractions are 0.5%and 2.0%,the elastic modulus of the composites correspondingly increases to 1.35 MPa and 3.9 MPa,and the flexural strength increases to 0.23 MPa and 0.32 MPa,respectively.In addition,the resistivity of the composite decreases with the increase of CNF mass fraction,the resistivity decreases to 46 Ω·m when the CNF mass fraction is up to 2.0%,and the added CNF is beneficial to the enhancement of the conductivity of the ash-based geopolymer composites.At the condition of the unidirectional pressurization experiment,the sensing sensitivity of the composite is 71.56,57.33 and 25.58 when the CNF mass fraction is 0.5%,1.0%and 2.0%,respectively.With the increaes of CNF mass fraction,the sensing sensitivities of the ash-based geopolymer composites firstly increase and then decrease,and the concentration threshold is between 0 and 0.5%.At the condition of CNF mass fraction of 0.5%,the sensing performance of the composites is relatively stable.
geopolymercarbon nanofibersensing performancestructural health monitoring
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维普
