From the January-February 2011 issue

摘要

The lack of durability in concrete structures worldwide demands fast and durable repairs. To address this need, high-early-strength engineered cementitious composites (HES-ECC) were recently developed for concrete repair applications, in which minimum operations disruption is desired. A detailed characterization of HES-ECC's compressive, tensile, flexural, and shrinkage properties at different ages is reported in this paper. HES-ECC achieves a compressive strength of 23.59 ± 1.40 MPa (3422.16 ± 203.33 psi) in 4 hours and 55.59 ± 2.17 MPa (8062.90 ± 315.03 psi) in 28 days. Under uniaxial tension, HES-ECC exhibits tensile strain-hardening behavior with a strain capacity greater than 2.5%. Its flexural strength exceeds twice that of concrete with similar compressive strength. Under restrained shrinkage conditions, HES-ECC forms microcracks with a self-controlled crack width below 50 μm (0.002 in.). The combination of these properties suggests that HES-ECC material is highly suitable for fast and durable concrete repairs with shortened downtime and improved long-term durability.