Modeling of the influence of fibers on creep of fiber reinforced cementitious composite

An analytical model has been developed to study the influence of fibers on creep of fiber reinforced cementitious composites. The model is based on the assumption that shear stress is produced between fiber and surrounding matrix as the matrix deforms. This shear stress in turn influences the matrix creep behavior resulting in macroscopic creep strain lower than that of pure cement-based matrix. In the present paper, a creep strain expression in the form of matrix creep strain multiplying by a fiber influence factor, which reflects the influences of matrix and fiber properties as well as fiber orientation characteristics, is presented. A parametric study, including the influence of elastic moduli of fiber and matrix, fiber dimension and fiber content is carried out. The modeling results indicate that creep strain of fiber reinforced cement-based composite is significantly influenced by the elastic moduli of fiber and matrix as well as fiber length and thickness (i.e. diameter for fiber with circular cross-section). Model predictions compare favorably with experimental measurements of creep strain of fiber reinforced mortar and concrete under compressive load.