Author/Authors :
Sarsam، Saad Issa نويسنده Professor of Transportation Engineering, Department of Civil Engineering, College of Engineering, University of Baghdad, Iraq , , AL-Shujairy ، A نويسنده Department of Civil Engineering, College of Engineering, University of Baghdad, Iraq. ,
Abstract :
Roller compacted asphalt concrete slab samples with dimension of (300x400) mm, 60 mm thick were prepared in the laboratory under controlled conditions. Forty-eight core specimens with diameter of 100mm and 60mm thick have been obtained from Roller compacted slabs, and were implemented for resilient modulus (Mr) and rutting resistance determination under indirect tensile repeated loading (ITRL), with constant stress level. Half of the cores were directly tested at 25° C and 40° C (unconditioned). The other half of cores were conditioned by placing in volumetric flask 4000-ml filled with water at room temperature of 25?C, then a vacuum of (3.74 kPa) was applied for 10 minutes to obtain 80 % degree level of saturation. The specimens were then placed in deep freeze at (-18?C) for (16) hours. The frozen specimens were then moved to a water bath for (24) hours at (60?C). Then they were placed in a water bath at (25?C) or 40 ?C for 1 hour, and they were tested for ITRL (conditioned). It was concluded that the change in permanent deformation at Conditioned test as compared to unconditioned test was ( 88.19%, 88.01% and 108.09% ) at 25?C, while at 40?C it was ( 20.89%, -1.14% and 19.46%) for recycled mixtures with Soft Asphalt cement (Ac), (Soft Ac + Silica Fumes) and (Soft Ac+ Fly ash) respectively. The reduction in (Mr) at Conditioned test as compared to Unconditioned test was (-3.7%, -16.67% and -7.69%) at 25?C, while at 40?C, it was (-6.25%, -14.29% and -7.14%) for recycled mixtures with (Soft Ac), (Soft Ac + Silica Fumes) and (Soft Ac + Fly ash) respectively.
