The invention provides a method for simultaneously preparing pull-out samples of single fibers in
cement matrixes with different thicknesses and application of the pull-out samples. The
sample preparation mold comprises a bottom plate, a back plate, a baffle plate, a sample separation module and a thick bottom
regulator which are fixedly connected through screws and
mortise and tenon joint structures. The back plate and the sample separation module are composed of an upper part and a lower part; grooves for determining
fiber positions are formed in the upper surfaces of the lower back plate and the bottom plate; the
cement base body is placed in a groove formed by the back plate, the baffle plate and the sample separation module; the thickness of the
fiber embedded in the
cement matrix can be achieved by rotating the thickness adjuster to move the lower sample separation module. The invention provides a
casting and stripping method of a single-
fiber pull-out sample based on the mold and a testing method of the single-fiber pull-out sample, and the
casting and stripping method and the testing method are applied to measuring the
critical length of single-fiber pull-out. Through integrated mold design, pulling-out samples of fibers in cement-based materials with different thicknesses can be prepared at the same time, and the
critical length that the fibers are pulled out of a matrix without breakage is further obtained. The method can fundamentally ensure that all contrast samples have high consistency in material composition, maintenance history and interface
microstructure, so that the matrix thickness is used as a unique independent variable for accurate research, the
test efficiency is remarkably improved, and the method is widely applied to the field of fiber reinforced cement-based materials.