Effect of short, dispersed glass and carbon fibres on the behaviour of textile-reinforced concrete under tensile loading

This paper addresses the influence of the addition of short, dispersed fibres made of alkali-resistant (AR) glass and carbon on the fracture behaviour of textile-reinforced concrete (TRC). A series of uniaxial, deformation-controlled tension tests was performed to study the strength, deformation, and fracture behaviour of thin, narrow plates made of TRC with and without the addition of short fibres. Furthermore, multifilament-yarn pullout and single-fibre pullout tests were carried out to gain a better understanding of the crack-bridging behaviour which suppresses growth and widening of cracks. Pronounced enhancement of first-crack stress was achieved, the value increased by factors of 1.5 and 2 due to the addition of glass and carbon fibres, respectively. While more and finer cracks were observed on the specimens with short fibres added, a moderate improvement in tensile strength was recorded. Water-to-binder ratio influences the matrix–fibre bond quality and thus fibre failure mode. While fibre fracture dominated behaviour when matrix M030 (low water-to-binder ratio of 0.30) was used, pronounced pullout behaviour was observed for fibres embedded in the matrix with a higher w/b ratio (M045). Furthermore, it was found that short fibres can also improve the bond between multifilament-yarns and the surrounding matrix by means of new cross-links.

► Short fibres influence positively the mechanical performance of TRC.
► Advantages of the addition of short dispersed fibres fade with increasing strain.
► Addition of short fibre to TRC leads to more and finer cracks.
► Short fibres improve the bond between yarns and matrix by means of cross-links.
► Mechanisms of the influence of short fibres are explained.