Self-sensing engineered cementitious composites with carbon nanotubes and reinforcing fibers for damage detection

Engineered Cementitious Composites (ECC) represent innovative construction materials that exhibit established mechanical properties and strength features. The exceptional characteristics of this substance render it a compelling option for various kinds of facilities. However, the increased implementation of ECCs necessitates monitoring the structural integrity of the systems that utilize them. This paper focuses on developing this concept by employing the traditional matrix after incorporating it with conductive fillers. These fillers transform the matrix into a functional state to sense the damage caused by various loads. Such loads include indirect tensile loads and compressive strength of mortar samples composed of cementitious matrix injected with multi-walled carbon nanotubes (MWCNT) and reinforced once with polyvinyl alcohol fibers (PVA) and with nylon fibers (NF) at another time, with different study ages of 28, 56, 90, and 180 days of curing with water at room temperature. In order to develop previous works and fill part of the gap, the traditional matrix was injected with carbon nanotubes at a dose of 0.5 by weight of cementitious materials with one of the reinforcement fibers of (PVA) or (NF) at a rate of 2% by the total volume of the mixture, which is a constant ratio throughout the study. In addition, a control mix free of additives was created for comparison. The results indicate that clever matrices have excellent mechanical properties. The PVA fiber-reinforced matrix performed better than the other matrices under applied loads. The electrical properties of the matrices were recorded from the start of load application and increased with increasing load. The CNT0.5PVA2 matrix had more gains under compressive loading, with a self-sensing ratio reaching about 200%. In split tensile loading, the CNT0.5NF2 matrix had a higher electrical resistance by about 20% than the CNT0.5PVA2 matrix, which had a resistance of less than 10%.