Flexural Behavior of Recycled Asphalt Concrete

Abstract

The operational health of the road network is of the utmost importance for economic and social life. Fatigue life is affected by the growth and accumulation of cracks, under the action of repeated vehicular loading, aging and effect of the environment. The flexural behavior of asphalt concrete depends mainly on the flexibility of the pavement mixture which deteriorate gradually with time. Recycling could be a suitable action to reserve such properties. In this investigation, beam specimens of (400 mm) length, a width of (80 mm), and a height of (50 mm) have been prepared from RAP as well as recycled asphalt concrete with cutback and emulsion. Beam specimens were subjected to repeated flexural stresses in a four-point loading system of 600 load cycles at 20°C. Loading of 138 kPa was applied in the form of rectangular wave with a constant loading frequency of 60 cycles per minute and loading sequence for each cycle is 0.1 sec load duration and 0.9 sec. The vertical deflection during the test of the beam at the mid span was measured with LVDT, which in turn was connected to data acquisition system where the deflection at various time intervals was stored and analyzed for finding strain at any number of cycles desired for every test. The resilient modulus was calculated and compared for various mixtures. It was concluded that the change in tensile strain for recycled mixtures compared with aged mixture at temperature 20°C was (16.5 and 22.2) % for recycled mixture with cutback and emulsion respectively. The reduction in Resilient Modulus under flexural stress for recycled mixtures with (cutback and emulsion) as compared of the aged mixture was (10.4 and 19.4) % respectively.