Fatigue resistance of dynamically loaded self-compacting concrete

摘要

The phenomenon of concrete fatigue is well documented in the literature for traditional concrete (TC), but this is not the case for self-compacting concrete (SCC). However, both concrete types differ substantially in composition and it remains to be seen whether all relevant mechanical properties including crack propagation and fatigue resistance are equal for SCC and TC mixtures of equal compressive strength. In this work, 32 reinforced concrete beams with varying reinforcement ratios and varying vertical stirrup quantities were subjected to static and dynamic loading until failure in a four-point bending rig. SCC and TC of equal compressive strength were delivered by a ready-mix concrete supplier. The imposed stress levels for dynamic loading were 0.1.f_(cc)-0-75f_(cc), 0-10f_(cc)-0-80f_(cc) and 0-10f_(cc)-0-85f_(ct) Structural behavioural properties such as deflections, strains and crack propagation corresponding to both static loads and fatigue loads were registered, and failure mechanisms during and after collapse were observed and analysed. The main conclusions are: different locations and types of failure were registered for ultimate load and fatigue load; the average crack width during static tests was smaller for SCC than for TC; for rebar fatigue failure, no difference was observed between SCC and TC; SCC appeared to have a higher direct compressive fatigue; crack width evolution during fatigue testing was substantially different for SCC and TC.