Influence of NMAS and groove depths on the static and fatigue shear performance of aggregate interlocking in PQC mixes

Abstract

ABSTRACT In the present study, a new test methodology is proposed to characterise the shear transfer ability of aggregate interlocking in pavement quality concrete (PQC) cylindrical specimens by conducting the direct shear test in the laboratory. The influence of the nominal maximum aggregate size (NMAS) and groove depth (GD) on shear strength (τ), joint shear stiffness (K) and fracture energy mode – II (G IIF) of aggregate interlocking in pavement quality concrete (PQC) are studied under static loading. A relationship between G IIF and K is determined. Also, shear fatigue test is conducted at higher stress levels to evaluate the effect of NMAS and GD on the performance of aggregate interlocking in PQC specimens at the grooved cross-section. From the Anderson–Darling statistic test, it is found that obtained fatigue results follow three-parameter Weibull distribution. The shape parameter (β) of the distribution is between one and two, which indicates that failure is due to wearing action. It is concluded that the proposed method in this research can be effectively used to evaluate τ, K and G IIF of aggregate interlocking in PQC specimens. Also, the use of larger NMAS in the PQC mix significantly improves the performance of aggregate interlocking under shear fatigue loading.