Effect of fiber content on mechanical parameters and crack development of two kinds of reinforced cement soil

Abstract

PVA fiber and basalt fiber are two kinds of common fibers used to reinforce cementitious materials and are widely used in engineering, therefore it is of great interest to study the effect of the content of the two kinds of fibers on the strength change of the cementitious materials. In this study, the unconfined compressive strength(UCS) test and digital image correlation (DIC) test of cement soil with different contents (0,0.25%, 0.5%, 0.75% and 1%) were carried out. The following conclusions were drawn: in the process of uniaxial compression, the curve of specimens can be roughly divided into five stages : compaction, elasticity, plastic yield, failure and residual stage; the UCS of the soil specimens increased with the increase with the content of the two kinds of fibers, the UCS of 1 % PVA fiber can be increased to 179.32 % of the control group, but when the content is greater than 0.75%, the development of strength was limited by fiber aggregation; The modulus of deformation and the compressive toughness index of the soil specimen are linearly related to the compressive strength; DIC technology can simply and efficiently monitor the horizontal strain field changes and crack development of specimens in several stages, which can be extended to the actual project.