Facile synthesis of novel dopamine-modified glass fibers for improving alkali resistance of fibers and flexural strength of fiber-reinforced cement

Glass fiber-reinforced cementitious material is one of the significant components in structural materials playing vital roles in enhancing the tensile and flexural behavior of cement-based quasi-brittle materials. Compared with carbon and polymer fibers, its intrinsic similar silicate-based composition to cement was endowed with better bonding properties and compatibility with cement-based materials. However, the poor alkali resistance of glass fibers restrained their potential development for spreading to applications in construction fields. In this study, dopamine-modified glass fibers (DP) were self-polymerized at ambient temperature by a facile method for enhancing the alkali resistance of glass fibers. Scanning electron microscopy and X-ray photoelectron spectroscopy were utilized for characterizing DP. The duration of reaction and fiber to solution ratio were adjusted with an optimal reaction time of 12 h and fiber to solution ratio of 0.12 g ml(-1) acquired. Alkali resistance was measured by strength retention tests in both mortar and sodium hydroxide solution. Compared with untreated glass fibers (UN), DP exhibited a distinct improvement in strength retention rate of 37.1% and 18.9% under mortar and sodium hydroxide solution environments, respectively. Also, flexural strength tests of DP-reinforced cement were conducted, and its strength was increased in comparison with that of UN-reinforced cement by 58.2%. As a consequence, a novel simple method for improving the alkali resistance of glass fibers was proposed and is anticipated to promote the development and applications of glass-fiber reinforced cement-based materials.

Automated summary

In this study, dopamine-modified glass fibers were successfully synthesized to enhance the alkali resistance of glass fibers, showing significant improvements in strength retention rate and flexural strength. This novel method is expected to promote the development and applications of glass-fiber reinforced cement-based materials.