Shrinkage characteristics of structural nano-synthetic fibre-reinforced cementitious composites

Cracks in cement composites act as penetration paths for exposure and structural deterioration, in addition to degrading the appearance of the cement. In particular, cracks can easily appear in both thin and wide slabs due to the large area exposed to ambient conditions. Small slab cracks quickly become larger when exposed to loads, which can lead to fatigue failure and a reduction in service life. To prevent such failures, joints can be installed at specific intervals within a slab to prevent random cracks. However, if these joints are installed without considering how the material will shrink, then these joints may introduce structurally vulnerable points. Using a mortar plastic shrinkage test, we evaluated shrinkage propensity in structural nano-synthetic fibre-reinforced cement composite over time; these results were compared with those of hooked-end-type steel fibre material. Based on the test results, a model was created to best reflect the properties of our composite among existing dry shrinkage models, to determine the optimal joint spacing for shrinkage behaviour compensation.