Flexural Strength Behavior of Composite UHPFC - Existing Concrete

Abstract

Ultra high performance fiber concrete (UHPFC) is an advanced formula concrete that is proven to be more superior than conventional concrete because it embrace the qualities of steel and concrete. Therefore UHPFC properties which include high durability and strength are fully exploited in the research of rehabilitation and strengthening in concrete and even non-concrete structures. This article presents the findings of an experimental study carried out to examine the bonding strength behaviour between normal concrete (NC) substrate and UHPFC as a repair material, under flexural strength test by using third-point loading beam test method. Three types of NC substrate surface preparation were used: as-cast (without surface preparation) as a reference, wire-brushed, and sand-blasted. The flexural test results clearly indicated that all failures occurred through the NC substrate and no de-bonding was observed in the interface between NC substrate and UHPFC. The results of the flexural strength confirmed that adhesion bond strength between NC substrate and UHPFC was stronger than the substrate regardless, the substrate roughness. This proves that UHPFC is able to link and bond strongly with the substrate.