科研之友
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摘要
The mechanistic performance of hybrid asphalt-concrete mixture incorporating coarse recycled concrete aggregate (RCA) was investigated. The hybrid mixture (W3B-RCA-C37) and control mixture (W3B-granite) were evaluated by the Marshall mix design method to determine their optimum asphalt content. Both W3B-RCA-C37 and W3B-granite mixtures had similar optimum asphalt content. However, volumetric properties (voids in total mix, voids filled by asphalt, and voids of mineral aggregate) of W3B-RCA-C37 mixture at its optimum asphalt content were lower than that of W3B-granite mixture. The Marshall stability, resilient modulus, and creep resistance of W3B-RCA-C37 mixture were higher than that of W3B-granite mixture, but it was more susceptible to moisture damage. The substitution of coarse RCA affected the mixture%26apos;s performance in several ways. Equivalent mass substitution of the aggregate resulted in relatively larger RCA volume per unit mass of the mixtures. Friable RCA induced greater aggregate breakages; broken aggregates may easily reorientate and fill available space in the mixture, resulting in a lesser space for air voids and effective asphalt. More asphalt was absorbed into the aggregates in W3B-RCA-C37 mixture but lesser asphalt was needed to fill the voids between the more tightly packed aggregates. Incorporation of RCA had resulted in a mixture with denser aggregate structure and a thinner asphalt film, giving higher Marshall stability and better deformation resistance. However, thinner asphalt film and inadequately coated broken aggregates increase susceptibility to moisture-stripping damage to the mixture.
- 出版日期2013-9-1
