Characterising the time-dependant behaviour on the single fibre level of SHCC: Part 1: Mechanism of fibre pull-out creep

• Published in: Cement and concrete research Vol. 39; no. 9; pp. 779 - 786
• Main Authors: Boshoff, William P., Mechtcherine, Viktor, van Zijl, Gideon P.A.G.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.09.2009; Elsevier
• Subjects: Applied sciences; Buildings. Public works; Concretes. Mortars. Grouts; Creep; Exact sciences and technology; Fibre pull-out; Fibre reinforcement; Materials; Other special applications (sand concrete, roller compacted concrete, heavy concrete, architectural concrete, etc.); Shrinkage; Tensile properties; Shrinkage; Creep; Tensile properties; Fibre pull-out; Fibre reinforcement; Pull out resistance; Mechanism analysis; Construction materials; Fiber reinforced material; Experimental study; Composite material; Tensile strength; Characterization; Time dependence; Experimental result; Hardened cement paste; Concrete; Behavior
• ISSN: 0008-8846; 1873-3948
• DOI: 10.1016/j.cemconres.2009.06.007

SHCC (Strain Hardening Cement-based Composite) has been designed and optimised to overcome the main weaknesses of ordinary concrete, which is its brittleness. SHCC shows a high tensile ductility and can resist the full load at a tensile strain of more than 4%. An in depth investigation into the time-dependant behaviour is still lacking for SHCC. This paper is the first part of a two paper series about the time-dependant behaviour on the single fibre level. In this paper, the tensile creep behaviour of SHCC is studied to distinguish mechanisms of creep. Tensile creep and shrinkage test results are reported for dumbbell type SHCC specimens. The specimens are pre-cracked to simulate in-service conditions, with subsequent sustained load at various levels, here chosen as 30%, 50%, 70% and 80% of the ultimate resistance. To distinguish the sources of significant creep deformation under these sustained loads, single fibre pull-out tests are performed under sustained load. It is shown that the time-dependent fibre pull-out is a significant source of time-dependent deformation, along with the formation of new cracks in SHCC under sustained load.