On durability of SHCC

Abstract

Strain-hardening cement-based composites (SHCC) resist increased tensile stress after first crack formation, over a significant range of tensile strain. This increased strength and strain capacity is achieved by effective crack bridging by fibres, across multiple cracks of widths in the micro-range. Whether the crack width limitation translates into increased durability through retardation of ingress of moisture, gas and other deleterious matter, is scrutinised in this paper. This is done by evaluation of recent test results from several laboratories internationally. The question whether these small crack widths are maintained under sustained, cyclic or other load paths is also addressed, concluding that the crack widths are not independent of the loading path. This contribution summarises the State-of-the-Art- Report prepared in the period 2005 to 2009 by RILEM TC 208-HFC, Subcommittee 2: Durability of SHCC. The potential of the comparatively new composite material becomes obvious, yet it is clearly outlined that further research is necessary before we fully understand the basic mechanisms underlying deterioration of SHCC. The JSCE Recommendation for design and construction of high performance fibre-reinforced composites with multiple fine cracks (HPFRCC) is a useful tool but it should be complemented by a similar recommendation on service life design in the future. Copyright © 2010 Japan Concrete Institute.