Title: Relationship of Rheology, Fiber Dispersion, and Strengths of Polyvinyl Alcohol Fiber-Reinforced Cementitious Composites
Author(s): Mingli Cao, Wen Si, and Chaopeng Xie
Publication: Materials Journal
Appears on pages(s): 191-204
Keywords: fiber dispersion; fiber factor; flexural strength; orientation coefficient; rheological performance
Polyvinyl alcohol (PVA) fiber with high elastic modulus and toughness can act as a reinforcing material to improve the brittleness of cement-based materials. However, the difficulty of fiber dispersion in the matrix is correspondingly increased due to its bending and clustering. Poor fiber dispersion not only deteriorates the mechanical properties of PVA fiber-reinforced cementitious composites (PVA-FRCCs) but also increases the difficulty in determining the relationship between fiber dispersion and hardening properties. Rheology, as a vital method to supervise the mixture properties, can improve the fiber distribution and optimize the hardening performance. This paper investigated rheological performance, fiber dispersion, and strengths of three types of PVA-FRCCs and discussed the effect of different fiber factors on the materials properties. Results showed that the rheology of a mixture can affect fiber dispersion and uniform fiber dispersion can be achieved through the experimental design of PVA-FRCCs. Besides, the quantitative relationship between fiber distribution parameters and flexural strengths of PVA-FRCCs was proposed, which showed a superior reliability than the composites theory formula and other traditional fitting equations. However, the relationship between fiber dispersion and compressive strengths was hardly founded due to the deterioration in compressive strength caused by the addition of PVA fibers.