Smart Graphite–Cement Composite for Roadway-Integrated Weigh-In-Motion Sensing

Abstract

Smart multifunctional composites exhibit enhanced physical and mechanical properties and can provide structures with new capabilities. The authors have recently initiated a research program aimed at developing new strain-sensing pavement materials enabling roadway-integrated weigh-in motion (WIM) sensing. The goal is to achieve an accurate WIM for infrastructure monitoring at lower costs and with enhanced durability compared to off-the-shelf solutions. Previous work was devoted to formulating a signal processing algorithm for estimating the axle number and weights, along with the vehicle speed based on the outputs of a piezoresistive pavement material deployed within a bridge deck. This work proposes and characterizes a suitable low-cost and highly scalable cement-based composite with strain-sensing capabilities and sufficient sensitivity to meet WIM signal requirements. Graphite cement-based smart composites are presented, and their electromechanical properties are investigated in view of their application to WIM. These composites are engineered for scalability owing to the ease of dispersion of the graphite powder in the cement matrix, and can thus be used to build smart sections of road pavements. The research presented in this paper consists of electromechanical tests performed on samples of different amounts of graphite for the identification of the optimal mix in terms of signal sensitivity. An optimum inclusion level of 20% by weight of cement is obtained and selected for the fabrication of a plate of 30 × 15 × 5 cm3. Results from load identification tests conducted on the plate show that the proposed technology is capable of WIM.

Hybrid Carbon Microfibers-Graphite Fillers for Piezoresistive Cementitious Composites

“…Resistivity measurements were taken 30 days after fabrication on unloaded samples ( ), following [ 17 ] for consistency. Results are plotted in Figure 5 , showing the average and the maximum/minimum values under each doping levels arranged by volumetric fractions of G and CMF ( Figure 5 a).…”

“…This can be attributed to the materials being overpercolated. Electrical results are to be compared with the outcomes of the measurements on 100th day graphite-only doped samples tested under the same load history [ 17 ].…”

“…This can be attributed to the materials being overpercolated. Electrical results are to be compared with the outcomes of the measurements on 100th day graphite-only doped samples tested under the same load history [17]. Results from the signals show that samples 1-32CMF10G exhibit the best signal quality in terms of polarization-drift and noise.…”

“…Among common conductive fillers, carbon nanotubes are reported to percolate between 0.75% and 1% weight ratio to the cement [ 14 ], and graphite around 20%: this difference is due to their different aspect ratio. [ 15 , 16 , 17 ].…”

A Review on Acoustic and Skid Resistance Solutions for Road Pavements

“…Nonetheless, with respect to their use in HiFASPs and other severe wearing surface conditions, additional research must be conducted to guarantee their durability, recyclability, and avoid any potential environmental impact. Finally, it is straightforward that the use of artificial engineered aggregates can provide opportunities in the ways of smartening the pavements by embedding specific sensors and carrying different materials that can provide self-healing, self-sensing, and temperature-controlling features in the pavement layers [85,86].…”