Effect of water saturation on the electrical properties of cement and alkali-activated slag composites with graphite conductive admixture

Effect of water saturation on the electrical properties of cement and alkali-activated slag composites with graphite conductive admixture

Článek WoS

This study investigated the influence of water saturation degree on the electrical properties of two different types of building materials – Portland cement and alkali-activaed slag mortars with graphite powder as a conductive admixture. The graphite content ranged between 0–18 wt.% of the cement/slag in order to cover the area below as well as above the percolation threshold. The properties were tested in terms of electrical resistivity measurement with an AC-frequency in the range of 40 Hz – 1 MHz, and the results were correlated with meso-scale structural changes evaluated by means of mercury intrusion porosimetry and scanning electron microscopy. The electrical resistivity of both materials decreased with increasing AC-source frequency and increasing water saturation degree. In a dry state, alkali-activated slag exhibited approximately ten times lower resistivity than cement-based material. The additon of graphite gradually decreased the resistivity until the percolation threshold was reached, but no influence of moisture on the resistivity was observed at dosages exceeding 12 wt.% of graphite. The dependance of electrical resistivity on the water saturation degree was fitted for two different frequencies (50 Hz and 1 kHz) using a sigmoidal regression function.

This study investigated the influence of water saturation degree on the electrical properties of two different types of building materials – Portland cement and alkali-activaed slag mortars with graphite powder as a conductive admixture. The graphite content ranged between 0–18 wt.% of the cement/slag in order to cover the area below as well as above the percolation threshold. The properties were tested in terms of electrical resistivity measurement with an AC-frequency in the range of 40 Hz – 1 MHz, and the results were correlated with meso-scale structural changes evaluated by means of mercury intrusion porosimetry and scanning electron microscopy. The electrical resistivity of both materials decreased with increasing AC-source frequency and increasing water saturation degree. In a dry state, alkali-activated slag exhibited approximately ten times lower resistivity than cement-based material. The additon of graphite gradually decreased the resistivity until the percolation threshold was reached, but no influence of moisture on the resistivity was observed at dosages exceeding 12 wt.% of graphite. The dependance of electrical resistivity on the water saturation degree was fitted for two different frequencies (50 Hz and 1 kHz) using a sigmoidal regression function.

Portland cement; slag; alkaline activation; moisture; electrical resistivity

Portland cement; slag; alkaline activation; moisture; electrical resistivity

ROVNANÍK, P.; KUSÁK, I.; BAYER, P.

2023

12.11.2022

Elsevier

0950-0618

Construction and Building Materials

361

129699

Spojené království Velké Británie a Severního Irska

11

https://doi.org/10.1016/j.conbuildmat.2022.129699