A method of mortal cement hardening and fracture behaviors tracking using the graphite paper sensor

This research was initiated to track the hardening and fracture behaviors of mortar cement utilizing a more convenient and cost-effective method compared to other non-destructive evaluation techniques. In pursuit of this aim, we selected the graphite paper sensor (GPS) to track the hardening and fracture behaviors. The GPS was manufactured using A4-sized paper and 4B grade pencil. Probes were set to copper wire and silver particle adhesive. Adhesive tape was used to protect graphite lines and probes. Optimized condition of GPS was set with different graphite line lengths and drawing times. The optimized condition was set to 10 mm of graphite line length and five times of drawing. As the drawing time increased, the graphite line was cracked and delaminated, while graphite was covered in the broader area. The hardening process was tracked using GPS with different water ratios in the mortar cement mixture. The electrical resistance (ER) behavior of GPS was analyzed during the hardening process, and humidity in mortar cement decreased. We tracked the humidity using GPS in mortar cement, and the optimized condition of the cement mixture ratio can be determined. After the hardening of mortar cement, the mechanical property was evaluated using the splitting tensile test to evaluate the optimized condition of water contents in the cement mixture. We determined The complete hardening of the mortar cement was confirmed when the electrical resistance (ER) of the GPS returned to zero. We suggested that this comprehensive approach facilitated a thorough understanding of the hardening and fracture behaviors of mortar cement, and this data contributed to the development of more efficient and effective tracking techniques in this field. • Cost-effective sensor crafted from readily available materials for cement hardening tracking. • Optimal condition found at 20 mm graphite length and 10 drawing time to maximize sensor stability. • "ΔER = zero" indicates full hardening state, enhancing predictability. • ER measurement of graphite-cellulose sensor tracks fracture behavior, predicting crack acceleration.