FEM study on the shrinkage property of fiber reinforced mortar

The current paper presents the results of numerical study on the shrinkage property of synthetic fiber reinforced cement mortar, including the discussion about the influence of fiber geometry on the shrinkage performance of mortar matrix. Finite element method (FEM) was used to build the numerical models respectively for the free composite and constrained composite. Cooling method was used to simulate the shrinkage of mortar matrix. Based on the thermal-mechanical coupling analysis, shrinkage and average normal stress of the matrix were obtained. Examples show that increasing fiber volume fraction can take effects both on the decrease of shrinkage and average normal stress of mortar matrix. Although X-type fibers with elastic modulus higher than the matrix can provide better anti shrinkage property for free mortar, they will increase the average stress in the constrained mortar and thus increase the possibility of original micro-cracks in mortar matrix. X-type fibers with elastic modulus lower than mortar, rather than cylindrical fibers, are suggested for a better achievement in anti shrinkage and cracking control.