الفهرس 
ContentsOnly 14 pages are availabe for public view
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Abstract
Alternative materials ( low quality natural (raw) materials, waste materials, ~ustrial by-products and recyclable materials ) are being used increasingly in ~way construction. Existing flexible and portland cement concrete pavements ~resent readily available supplies of aggregates that can be recycled and contribute environmental preservation by reducing the amount of new materials required for ~way use. Thus, a corresponding reduction is possible in environmental problems .m mining the new materials and manufacturing the products, in addition to biding the problems associated with disposal of the old pavement materials.
This study deals with laboratory investigations into a comparison between lyclable and natural materials on the characteristics of unbound base course layers. It’tests was undertaken on four types of materials. Two recyclable materials, old ttland cement concrete pavement (crushed concrete) and old asphalt concrete ~ement (asphalt granulate), and two reference natural materials-crushed limestone I gravel-sand, and mixtures of these materials were tested.
A standardized evaluation of the properties of recyclable materials was not lsible until now, as there is no agreement on a universally recognized test ~ure. Therefore, the suitability of the application of the test methods for natural terials to recyclable material were also examined. Classification and identification ~ were performed first on all materials under investigation. Tests of sieve analysis, Wng-thawing, etc. were performed. The variables studied from the dynamic tests ’0000: material type , degrees of compaction and axial stress levels. Secondly, a igram of repeated load uniaxial test was carried out to investigate the influence of Se variables on the required parameters such as permanent strain and resilient ~ulus .
Comparison of the permanent strain and resilient modulus obtained from both es of materials clearly showed the permanent strain in crushed concrete to be lower ~ those occurring in natural materials and asphalt granulate. The resilient modulus ~es in crushed concrete were greater than those values occurring in crushed ~one at 106% degree of compaction. On the other hand, these values as indicated ~hed concrete, were greater than those values in asphalt granulate and gravel¬d at the same degree of compaction and stress level. Also, results of the testing
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~ indicated that, it was possible to use asphalt granulate mixtures to build the
~und base course layers as a substitute for natural materials under certain
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Wtions.