Reinforcement effect and mechanism of carbon fibers to mechanical and electrically conductive properties of cement-based materials

Abstract

In this paper, carbon fibers with hydrophilic surface modification were added into cement mortar through ultrasonic treatment. The mechanical and electrical properties of carbon fiber filled cement mortar were tested to examine the reinforcing effect of carbon fiber. In order to understand the underlying modification mechanisms of carbon fibers to cement mortar at micro scale and in theory, scanning electron microscope (SEM) observation and theoretical calculations were carried out. Test results indicate that the adding of carbon fibers into cement mortar enhances the mechanical strength (especially compressive strength), and decreases the electrical resistivity of carbon fiber filled cement mortar. SEM results show that the enhancement of the properties of carbon fiber filled cement mortar owes to fiber ability of restraining the growth of microcracks and absorbing energy by overcoming its pulling out. The enhancing mechanism of carbon fibers on the properties of cement mortar analyzed by the calculated fiber numbers per unit volume, average center distance between two carbon fibers and the critical pull-out length well matches the experimental results.

Theoretical and experimental analysis of multifunctional high performance cement mortar matrices reinforced with varying lengths of carbon fibers

“…The flattening pattern of center-to-center distance is more pronounced after 0.15 wt% inclusion of CFs. This phenomenon may be associated with the clumping and bundling of carbon fibers at higher concentrations (18). The clumping of fibers leads to heterogeneity inducing weak spots in the cementitious matrix.…”

“…strength and ductility) of composites (11)(12)(13)(14)(15)(16)(17). Beside strength and ductility, the fibers also improve the durability characteristics of the cementitious composites by refining their microstructure and restricting the development of induced micro cracks due to shrinkage and other chemical/physical phenomenon (18)(19)(20)(21)(22)(23). The mechanical and fracture behavior of FRCCs depend upon several factors such as fiber's volume, length, diameter, their dispersion and bonding with the host matrix.…”

Fracture toughness and failure mechanism of high performance concrete incorporating carbon nanotubes

“…0.41 L may be termed as critical pull-out length which may be evaluated from following expression [44]:…”

Effects of carbon additives on heat-transfer and mechanical properties of high early strength cement mortar

“…Consequently, there have been a wide number of studies that have explored carbon material reinforced composites, or reinforced concretes, to improve their thermal conductivity and mechanical properties. In particular, carbon blacks and carbon fibers are usually used as an additive to improve thermal properties as well as strength properties [11][12][13][14].To prevent mortar-based structures from freezing in the winter, mortars have to transfer heat efficiently from the heat source, such as geothermal heat or internal heater. In this study, to improve the heat-transfer properties of mortars for repair work, the effect of carbon black and carbon fibers on the heat-transfer properties of high early strength cement mortars was investigated.…”

“…Consequently, there have been a wide number of studies that have explored carbon material reinforced composites, or reinforced concretes, to improve their thermal conductivity and mechanical properties. In particular, carbon blacks and carbon fibers are usually used as an additive to improve thermal properties as well as strength properties [11][12][13][14].…”