Development and application of a high performance fiber reinforced self-compacting concrete in post-tensioning anchorage zones

Author(s): C. Marchão, S. Nunes, V. Lúcio, A. Brás, J. Figueiras
Paper category: Conference
Book title: 8th RILEM International Symposium on Fiber Reinforced Concrete: challenges and opportunities (BEFIB 2012)
Editor(s): Joaquim A.O. Barros
Print ISBN: 978-2-35158-132-2
e-ISBN: 978-2-35158-133-9
Publisher: RILEM Publications SARL
Pages: 457 - 469
Total Pages: 12
Language: English

Abstract: 
One of the most critical aspects in post-tensioned structures is the anchorage zones. Despite research works that have been published on this subject, problems during construction and throughout the life of these structures, such as cracking or local failures in anchorages zones, still occur. Apart from issues related to the design and safety assessment, the high density of steel reinforcement is the most common reason for problems with concrete cast in situ, resulting in sections with low compacity, hence leading to crush failures under the anchor plates. The solution of this problem may involve the reduction of reinforcement by improving the concrete compression and tensile strength.
Due to these requirements, a study was carried out to optimize a high-performance fibre reinforced self-compacting mortar mixture. The mixes were prepared with CEM I 42.5R, limestone filler, silica fume, natural sand (dmax=1 mm), superplasticizer, fibres (Ø=0.175 mm; l=6, 9, 12 mm) and tap water. The packing density was evaluated indirectly through the flow cone and V-funnel tests. For each tested mixture the indirect tensile and compressive strength tests were carried out on prismatic specimens (40X40X160 mm3). Compressive and splitting tensile strengths up to 127 MPa and 13 MPa, respectively, were achieved at 7 days, in current curing conditions.
Since the efficiency of this solution also depends on the ability to penetrate voids between reinforcement bars the workability loss was also studied. The workability behaviour was characterized by the rheological parameter yield stress, as well as the procedures of mini slump flow.
In order to assess both ultimate capacity and adequate serviceability of the local anchorage zone after reducing not only the minimum concrete cross-section but also the confining reinforcement, both specified by the anchorage device supplier for the particular tendon, an experimental program was carried out.

Online publication: 2013
Publication Type: full_text
Public price (Euros): 0.00