Self-Sensing Properties of Alkali Activated Blast Furnace Slag (BFS) Composites Reinforced with Carbon Fibers

Abstract

In recent years, several researchers have shown the good performance of alkali activated slag cement and concretes. Besides their good mechanical properties and durability, this type of cement is a good alternative to Portland cements if sustainability is considered. Moreover, multifunctional cement composites have been developed in the last decades for their functional applications (self-sensing, EMI shielding, self-heating, etc.). In this study, the strain and damage sensing possible application of carbon fiber reinforced alkali activated slag pastes has been evaluated. Cement pastes with 0, 0.29 and 0.58 vol % carbon fiber addition were prepared. Both carbon fiber dosages showed sensing properties. For strain sensing, function gage factors of up to 661 were calculated for compressive cycles. Furthermore, all composites with carbon fibers suffered a sudden increase in their resistivity when internal damages began, prior to any external signal of damage. Hence, this material may be suitable as strain or damage sensor.

Shrinkage and creep behavior of an alkali‐activated slag concrete

“… SiO 2 / Na 2 O ‐mole ratio and equivalent Na 2 O ‐content of the applied activator in the alkali‐activated slag ( AAS )‐concrete in comparison to literature references …”

Carbonized electrospun polyacrylonitrile nanofibers as highly sensitive sensors in structural health monitoring of composite structures

“…The strain gauge of the test setup provided a linear relationship between electrical resistances and strain values. The electrical resistance values were drastically decreased as a function of time . The electrical conductivity values of the carbonized electrospun PAN nanofibers can be significantly changed when they are mechanically loaded .…”

“…The contribution of Poisson's effect also plays a significant role . The resistivity and changes in dimension may have relationships when the material contains cracks, internal defects, and secondary phase formations . However, the relationship between dimensional changes and resistivity changes due to loading and unloading requires more research.…”

“…Even after the heat treatment below 1000°C, the fibers are not entirely composed of carbon, and the other elements still present in carbon fiber structures that can take part substantially in heterogeneity, and thus to the observation of the non‐ohmic behavior. When the PAN nanofibers are heat treated between 600 and 800°C temperature ranges, they become more conductors, and, thus, the heterogeneity was evidently most pivotal in determining the properties …”

“…Vilaplana et al . stated that the carbon fibers decreased the electrical properties under the applied loads and reported the electrical resistivity value of 0.0000152 m Ω . Luhrs et al .…”