Influence of silica fume on stress-strain behavior of FRP-confined HSC

Confinement of high-strength concrete (HSC) columns with fiber reinforced polymer (FRP) composites has been receiving increasing research attention due to the advantageous engineering properties offered by the composite system. The use of silica fume as a concrete additive is a widely accepted practice in producing HSC. However, the influence of presence and amount of silica fume on the efficiency of FRP confinement has not been clearly understood. This paper presents results of an experimental study on the influence of silica fume on FRP-confined HSC. Nine aramid FRP (AFRP)-confined and nine unconfined concrete cylinders were tested under axial compression. The change in the mechanical properties of FRP-confined and unconfined HSC with silica fume amount was investigated. The results indicate that the compressive strength of unconfined concrete increases with an increase in the amount of silica fume. However, this increase comes at a cost of increased concrete brittleness, which adversely affects the effectiveness of FRP confinement. These observations were further validated with 93 test results of FRP-confined HSC assembled from the published literature. The additional results from the database allowed further observations to be made on the influence of silica fume on the compressive behavior of FRP-confined HSC. This paper presents the findings of these investigations.