Effects of Fiber Dispersion and Flaw Size Distribution on the Composite Properties of PVA-ECC

摘要

Over the last decade, Engineered Cementitious Composites (ECC) containing Poly-Vinyl Alcohol fibers (PVA-ECC) have been extensively researched and used in a wide variety of structural applications utilizing the composite's high tensile ductility and durability. Fiber and flaw size distributions of PVA-ECC, which greatly affect its composite properties, have been studied in this research using fluorescence imaging and optical microscopy. Statistical analysis revealed a double-Gaussian best-fit distribution showing possible non-conservative preferential alignment of fibers in dogbone specimens along the longitudinal axis of the specimen. Maximum flaw sizes at various sections ranged from 0.6 to 6.3 mm with a combination of lognormal and Gaussian distributions best-fitting the observed data. The effects of the above statistical distributions on composite stress-strain behavior are studied using micromechanics and scale-linking models. The predicted composite properties are then compared with the experimental data of the direct uniaxial tension tests on PVA-ECC dogbone specimens.