Mechanical and dynamic properties of self-compacting crumb rubber modified concrete

In this study, the mechanical and dynamic properties of Self-Compacting Rubberised Concrete (SCRC) were experimentally investigated. Crumb rubber from scrap tyres was used as a partial replacement for Fine Aggregate (FA), Coarse Aggregate (CA) and combined Fine and Coarse Aggregate (FCA) at 5, 10, and 15 wt% proportions. Incorporating rubber aggregates generally has a detrimental effect on the mechanical strength, but gives improved strain capacity resulting in significant reductions in the flexural Crack Mouth Open Displacement (CMOD), compared to the reference mix. Structural grade SCRC (fc > 17 MPa; ρ > 2000 kg/m3) can be obtained with up to ∼260 kg/m3 (equivalent to 15 wt%) in all forms of crumb rubber aggregate substitution. The Dynamic Modulus and Ultrasonic Pulse Velocity decreased as the proportion of rubber substitution was increased, however SCRC has superior vibration damping behaviour in all cases with up to 230% enhancement in damping ratio and damping coefficient for the CR 15 wt% mix.

► Adding rubber to self-compacting concrete deteriorated the mechanical properties.
► SCRC can be used as a structural concrete in civil engineering applications.
► Considerable enhancement observed in flexural toughness with rubber addition.
► SCRC is suitable when dynamic response and vibration damping are a priority.