Saldanha, RuiSantos, PedroJúlio, Eduardo2026-03-172026-03-172013Saldanha, R., Santos, P., & Júlio, E. (2013). Influence of concrete density and Strength on the bond strength of composite members. In Conference Fib Symposium–Engineering a Concrete Future: Technology, Modeling and Construction Proceedings. Tel-Aviv, Israel: fib.978-965920390-1http://hdl.handle.net/10400.8/15899The present paper addresses the influence of both material density and strength in the adhesion between concrete layers cast at different ages. A Normal Oensity Concrete (NOC), a LightWeight Aggregate Concrete (LWAC) and an Ultra High Durability Concrete (UHDC) were considered. The latter is characterized by presenting enhanced durability properties. Nevertheless, the production of the UHDC presents both economical and environmental disadvantages. In order to minimize the impact of its use and, simultaneously, take advantage of its properties, it is proposed to use it only in the cover layer of structural members, being the bulk produced in ordinary concrete. An experimental study was conducted to characterize the adhesion between UHDC/NOC and UHDC/LWAC by means of the Modified Slant Shear Test (M-SST). This new bond test was developed by the authors to always ensure adhesive failures in composite specimens. Two different surface conditions were selected for the interface: i) smooth surface, as-cast against steel formwork; and ii) surface obtained by casting against a plastic wavy formwork. Experimental results are discussed and conclusions are drawn.engAdhesionBondConcreteInterfaceUltra High Durability Concrete (UHDC)conference paper