Loading rate effects on the properties of fiber-matrix zone surrounding steel fibers and cement based matrix

This study investigated the loading rate effects on the properties of fiber-matrix zone (FMZ) surrounding steel fibers by conducting nanoindentation tests. Ultra-high performance concrete (MU) produced the highest loading rate sensitivity (n) owing to the highest pressure hardening sensitivity of MU although both hardness (H) and Young's modulus (E) of FMZ of other two matrices also clearly increased as loading rate increased from 1 to 8 mN/s. The higher n of MU would be based on the higher content of ultra-high density calcium silicate hydrate. The C-S-H with higher calcium to silica ratio generated higher rate sensitivity. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study investigated the effects of loading rate on the properties of fiber-matrix zone surrounding steel fibers by conducting nanoindentation tests. Ultra-high performance concrete (MU) showed the highest loading rate sensitivity, possibly due to its higher content of ultra-high density calcium silicate hydrate. The results suggest that the higher loading rate sensitivity of MU may be attributed to its higher pressure hardening sensitivity.