Özet:

Waste concrete aggregates (WCA) are produced by crushing demolished concrete elements. WCA differ from fresh aggregates due to the cement paste attached to the surface of the original aggregates after the process of recycling. The highly porous cement paste and other contaminations contribute to the lower particle density and higher porosity, variation in the quality of the WCA and the higher water absorption. This paper presents some of the results of an investigation on the possible application of WCA in bituminous pavement. The laboratory investigation was divided into three distinct phases. At first all the physical properties of material such as coarse aggregate, fine aggregate, filler and bitumen were determined. The second phase consists of preparation of Marshall test specimens. The third and last phase consists of testing of specimens to obtain Marshall test properties. At first three specimens were prepared with bitumen content 5% for black stone (Type A), 5.5% for white stone (Type B), and 6.5%for WCA from black stone (Type C) and 7% for WCA from white stone (Type D). Five bitumen contents were used with increment of 0.5% for type A, B, C and D. Then the specimens were tested and Marshall stability were obtained 88.7kN, 10.5kN, 10.1kN and 9.2kN at optimum bitumen content 6.2%, 63.7%, 8.1% and 8.3% for mix type A, B, C, and D respectively. Amount bitumen per cubic meter of mix are 154 kg, 153.4 kg, 188 kg, 175.8 kg for mix type A, B, C and D respectively. Marshall test properties of mixes with WCA are satisfactory but required bitumen are 1.08, 1.31,1.34 times more for mix type B, C, and D than that of time A. Aggregates types C and D are acceptable from the consideration of strength properties. The investigated results indicate that the bituminous macadam base course with WCA from white stone give satisfactory results when they are constructed using dense grading, good compaction for medium traffic road.

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