Tensile Strain Reduction in Asphalt Concrete Mixtures through Rubberization at the Asphalt Bound – Subgrade Layer Interface

Abstract

Tensile strains are major contributors in determining the fatigue life of asphalt concrete pavement because they are responsible for fatigue cracking. Therefore, knowledge of strains and their role is of vital importance to the Highway Engineer. However, the focus of the present study was to investigate measures by which these damage contributing factor – “tensile strain” could be reduced at the interface of the asphalt concrete – subgrade layer. The methodology involved introducing rubber latex at the optimum asphalt content of the asphalt concrete mixtures in order to alter the properties of the concrete. Results revealed that the introduction of rubber latex at varying amounts of 0-3% into the asphalt concrete mixtures reduced the tensile strains from 9.74 × 104–4.27 × 104 at loading frequency of 1 Hz, 10.13 × 104–4.52 × 104 at loading frequency of 5 Hz and 10.87 × 104–5.46 × 104 at loading frequency of 10 Hz, respectively. In addition, results further revealed that as tensile strain levels reduced the fatigue life of the asphalt concrete in terms of no. of load cycles to failure increased. This was true for all categories of loading frequencies considered.