Destructive and non-destructive determination of resilient modulus of hot mix asphalt under different environmental conditions

Abstract

This paper reports the outcome of a study on the resilient modulus of hot mix asphalt characterised under different environmental conditions and testing methods with the intention of establishing the effects of climate and testing procedure for appropriate standardisation of laboratory and field quality control/assurance of pavement works. Destructive (DT) and non-destructive (NDT) tests were carried out on laboratory Marshall Specimens of an asphalt mix prepared for a specified pavement wearing course in Nigeria at three temperatures: 4, 25 (in dry air), 25 (soaked in water) and 50°C. The DT was achieved with the Marshall Stability apparatus for the indirect tensile strength while the non-destructive was accomplished with the portable ultrasonic non-destructive digital indicating tester. Sixty-four test specimens were conditioned to the three temperatures before conducting the strength characterisation exercise alongside the effect of delayed test for a few hours and 3 months. The moisture susceptibility damage of the hot mix asphalt was also assessed with the specimens at the prevailing laboratory room temperature of 25°C. Statistical analysis of variance test was carried out on the resilient modulus data base developed to establish the effects of the temperature and other treatments. The resilient modulus of hot mix asphalt decreased as the temperature increased, irrespective of the test method adopted, while the NDT method gave a more consistent result than the destructive, thereby recommended as a better quality control scheme during the construction of bituminous flexible pavement. The 3-month delay in testing the strength of asphalt does not significantly affect the value at 5% level of confidence.

Keywords::

• resilient modulus
• indirect tensile strength
• destructive and non-destructive
• treatment effects

Notes

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