Effects of Electrodes Layout and Filler Scale on Percolation Threshold and Piezoresistivity Performances of a Cementitious-Based Geocomposite

Abstract

An extensive experimental study was conducted to investigate the co-effects of surface area and distance between electrodes as well as filler scales on the percolation threshold of piezoresistive cement-stabilised sand. In this route, the electrical resistivity of numerous specimens of different sizes and composed of different content of carbon-based conductive fillers was measured, including carbon nanotubes (CNTs), graphene nanoplatelets (GNPs), and carbon fibres (CFs) with different aspect ratios. In addition, the numerical relations between the electrical percolation threshold and matrix dimensions were expressed for different conductive fillers. Furthermore, the electrical percolation threshold of two large-scale specimens with different shapes (a 10 × 10 × 85 cm3 beam, and a 15 cm size cube) were predicted through numerical relations, and their piezoresistivity performances were investigated under compression cyclic loading (cube) and flexural cyclic loading (beam). The mechanical properties of the specimens were also evaluated. The results showed that the changes in the length, width, and thickness of the matrix surrounded between electrodes had a significant effect on the electrical percolation threshold. However, the effects of length changes on the percolation threshold were greater than the width and thickness changes. Generally, increasing the aspect ratio of the conductive fillers caused a reduction in the electrical percolation threshold of the cementitious geocomposite. The appropriate piezoresistivity response of the large-scale specimens composed of filler content equal to their percolation threshold (obtained by the numerical relation presented in this study) showed the adequacy of the results in terms of threshold dosage prediction and self-sensing geocomposite design. The results of this study addressed a crucial factor for the design of self-sensing composites and pave the way for the development of field-applicable, smart, cementitious geocomposite.

The pioneer of intelligent and sustainable construction in tunnel shotcrete applications: a comprehensive experimental and numerical study on a self-sensing and self-heating green cement-based composite

“…Generally reinforcing the cement-based composites with a certain amount of the fibres can increase the flexural strength through the crack bridging and/or deviation. However, an excessive increase in the fibre concentrations increases the porosity of the composite due to the agglomeration formation reduces the flexural strength [41,49,65]. The augmentation of flexural strength in cement-based composites through fibre reinforcement can be rooted in several fundamental mechanisms.…”

“…Self-sensing concrete involves the incorporation of conductive fillers such as carbon nanomaterials (CNMs) and microfibres including steel and carbon fibres, forming a conductive network that can detect variations in strain, stress, or other structural parameters within the concrete [1,13,[36][37][38][39]. This real-time monitoring capability offers unprecedented insights into the structural health of the material, enabling early detection of potential issues and facilitating timely maintenance interventions [40][41][42][43][44][45]. Simultaneously, the inclusion of conductive fillers unlocks the potential for self-heating, where controlled electrical currents can be applied to induce localized heat within the concrete matrix [46].…”

“…It not only assists in cost reduction but also prevents the formation of agglomerations, which may result in physical impairment [40,48]. Based on the literature, various studies have been carried out on self-sensing and self-heating fibre-reinforced cementitious composite [1,36,41,47,49]. However, a conspicuous gap exists in the realm of comprehensive research pertaining to the self-sensing and self-heating shotcrete mixtures, with particular emphasis on the development of environmentally friendly, cost-efficient, sustainable, and practical composites tailored for infrastructure applications.…”

Influence of cement and water content on the multifaceted capabilities of a self-sensing cement-based geocomposite: a comprehensive analysis

“…This reduction in CNM concentration helps prevent agglomeration formation and lowers production costs. Additionally, they investigated the influences of various factors, including the type and quantity of conductive filler [49], the design of electrical circuits and electrode layout [50], fiber reinforcement [51], as well as environmental conditions such as humidity, temperature [52], and climatic cycles [48,53], along with different loading types [52]. These factors were examined concerning the mechanical, microstructural, and sensing performances of the self-sensing cementitious geocomposite.…”

Three-dimensional braided composites as innovative smart structural reinforcements

“…These monitoring techniques create local low-resolution detection systems for concrete structures [12][13][14]. Furthermore, these sensors have serious drawbacks, such as low durability, poor sensitivity, high cost of production, high time consumption, installation costs, and difficulties in assuring proper bond conditions with cementitious composite [15][16][17][18]. Among SHM techniques, carbon-reinforced braided composite rods (CBCRs) have provided a more reliable, real-time, and practical solution for concrete structure damage monitoring based on the piezoresistivity principle [1,19,20].…”