Influence of Steel Fibers on Damage Induced by Alkali-Silica Reaction of Concrete with Reactive Sudbury Aggregates

The main consequence of Alkali-Silica Reaction is the formation of cracks due to expansion, which can lead to a reduction in resistance capacity of the section of the structural element. The addition of steel fibers (micro fibers and Macro fibers) in the concrete, leads to considerable changes in the material properties in terms of its mechanical and durability performance, even under operating loads. This involves reducing or eliminating the formation of cracks, thus limiting the penetration of corrosive agents. In order to understand the behavior of steel fibers on concrete subjected to ASR due to the presence of highly reactive coarse aggregate (Sudbury aggregate), a 4-month accelerated laboratory testing campaign was conducted with four mix designs (plain concrete, 0.5% Macro fiber, 1.0% Macro fiber, 1.0% Hybrid: 0.5% Macro and 0.5% micro fiber). To speed up the ASR reaction process the samples were exposed to 50 degrees C temperature and 100% R.H. in a moisture chamber for the entire maturation period. Prisms, cubes, cylinders and beams were cast and tested for: longitudinal expansion, dynamic elastic modulus, damage rating index, compressive strength, static modulus of elasticity and flexural tensile strength. The main result was that the 1.0% Macro mix design is the one that most mitigates the formation of cracks.