Title: Bond of Reinforcement in Ultra High-Strength Concrete

Author(s): K. Holschemacher, D. Weiße, and S. Klotz

Publication: Symposium Paper

Volume: 228

Issue:

Appears on pages(s): 513-528

Keywords: bond behavior; concrete cover; reactive powder concrete (RPC); reinforcement; splitting; static loading; tensile strength; ultra high-strength concrete (UHSC)

DOI: 10.14359/14489

Date: 6/1/2005

Abstract:
Ultra high strength concrete (UHSC) is undoubtedly an engineered high-tech material, which can be seen as the latest step in the concrete technology development. Because this concrete type is relatively new, the structural behavior in the ultimate limit states as well as in the serviceability limit states is not fully investigated and understood, so is the bond behavior of reinforcement. An experimental program was set up to investigate the bond behavior of conventional reinforcement and of reinforcement with a new deep-ripped surface pattern in ultra high strength concrete. The assessment of the bond behavior at concrete ages of 3, 7, 28 and 56 days using pull-out specimens was the subject of the investigation. Varying parameters in this research program were rebar diameter, type of reinforcement, surface geometry of the rebar, size of the concrete cover and the loading rate. The concrete compressive and splitting tensile strength were measured at the same test ages. In general, the bond of reinforcement in UHSC is characterized by very high maximum bond stresses as well as high bond stiffnesses, even at early ages. The reinforcing mesh bars with the “deepribbed” surface showed a remarkable ductility. This paper presents the details of the investigation and discusses the results obtained.