Electrical Properties of Fly Ash Geopolymer Composites With Graphite Conductive Admixtures

Abstract

Construction materials with increased electrical conductivity could be possibly used in health monitoring of structures (stress, deformation, damages), their maintenance or traffic monitoring. The aim of this study was the application of functional filler and its influence on the electrical properties of the alkali-activated fly ash matrix. The graphite powder was added to the reference material in the amount of 2–10 %. Besides the assessment of the critical amount of filler necessary to achieve a percolation threshold in the structure of the composite, the effect on the electrical properties of the matrix (resistance, capacitance, conductivity) was determined. The optimal amount of filler was also determined with respect to the changes in microstructure of the binder and its mechanical properties.

Electrothermal effect of carbon fiber and graphite reinforced metakaolin‐based geopolymer

“…According to Zhang et al., 42 high graphite content in geopolymers can lead to agglomeration, defect formation, and strength reduction. In addition, the reduced strength can also be attributed to the weak bond between the geopolymer and graphite particles 43 . Interestingly, the addition of carbon fiber to GP‐1 slightly decreases its compressive strength in comparison to GP‐3.…”

“…The results indicated the similarities in porosity between all geopolymers. The incorporation of conductive additives has negligible influence on the pore structure of geopolymers; the reduction in strength of geopolymers when graphite is added is not due to the pore structure, but rather to the lower matrix strength and interface strength between graphite and geopolymers 43 …”

“…In addition, the reduced strength can also be attributed to the weak bond between the geopolymer and graphite particles. 43 Interestingly, the addition of carbon fiber to GP-1 slightly decreases its compressive strength in comparison to GP-3. This effect may be attributed to the reduced workability and flowability of the slurry due to the inclusion of carbon fiber, consequently leading to reduced compressive strength.…”

“…Thus, the micromorphology results suggest that the reduction in compressive strength is primarily due to the incorporation of graphite. Mizerová et al 43 discovered that the addition of graphite led to an increased presence of pores and inhomogeneities in the microscopic structure of geopolymers, consequently resulting in a reduction in strength. Thus, the addition of graphite resulted in a decrease in both microstructure and interface bond strength, particularly between graphite and geopolymer, ultimately affecting the overall strength.…”

The Variable Frequency Conductivity of Geopolymers during the Long Agieng Period

“…There are some investigations reported in literature focused on measuring resistivity of mortars and concretes [31][32][33][34][35][36][37]. The aim of these works was to increase conductivity, which is needed for health monitoring of geopolymer structure.…”