Tailoring SHCC made of two kinds of PVA fibers

Title: Tailoring SHCC made of two kinds of PVA fibers
Author(s): A. P. Fantilli, H. Mihashi, T. Naganuma, and T. Nishiwaki
Paper category : conference
Book title: International RILEM Conference on Advances in Construction Materials Through Science and Engineering
Editor(s): Christopher Leung and K.T. WAN
ISBN: 978-2-35158-116-2
e-ISBN: 978-2-35158-117-9
Publisher: RILEM Publications SARL
Publication year: 2011
Pages: 853 - 860
Total Pages: 8
Nb references: 7
Language: English

Abstract: Some Fiber-Reinforced Concrete (FRC), commonly called Strain-Hardening Cement-based Composite (SHCC), can show a very ductile behavior under tensile actions. Specifically, in the post cracking stage, several cracks develop before complete failure, which occurs when tensile strains localize in one of the formed cracks. As is well known, multiple cracking and strain hardening can be achieved in cement-based specimens subjected to uniaxial tension by increasing the volume fraction of steel fibers with hooked ends, or by using plastic fibers with and without steel fibers, or by means of high bond steel fibers (e.g., twisted fibers or cords). To better understand why, in such situations, high mechanical performances are obtained, an analytical micro-mechanical model has been proposed. The model, capable of predicting the average distance between cracks as measured in some experimental campaigns, is here used to achieve a strain-hardening behavior in a more cost-effective FRC. Specifically, a new Hybrid Fiber Reinforced Concrete, made with two different types of PVA fibers, has been developed at Tohoku University of Sendai (Japan). By means of the shorter and thinner PVA fibers (diameter = 0.04 mm; length = 6 mm), it is possible to enhance the toughness of the cement-based matrix, whereas longer fibers (diameter = 0.1 mm; length = 12 mm) bridge the macro-cracks. By combining direct uniaxial tensile tests, performed on the so-called dumbbellshaped specimens, and the results of the micro-mechanical model, the critical value of the fiber volume fraction can be evaluated. It should be considered as the minimum amount of longer fibers which can lead to the formation of multiple cracking and strain hardening under tensile actions. The aim of the present paper is to reduce such volume as much as possible, in order to improve the workability and reduce the final cost of SHCC.

Online publication: 2011-10-31
Publication type : full_text
Public price (Euros): 0.00