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原文传递 DEVELOPMENT OF VOID PATHWAY TEST FOR INVESTIGATING VOID INTERCONNECTIVITY IN COMPACTED HOT-MIX ASPHALT CONCRETE.

题名：	DEVELOPMENT OF VOID PATHWAY TEST FOR INVESTIGATING VOID INTERCONNECTIVITY IN COMPACTED HOT-MIX ASPHALT CONCRETE.
作者：	Hall-KD; Ng-HG
关键词：	Air-voids; Asphalt-concrete; Darcy'-s-law; Hot-mix-asphalt; Hot-mix-paving-mixtures; Location-; Permeability-; Permeameters-; Size-; Superpave-; Test-procedures; Void-interconnectivity
摘要：	In response to reports of moisture "weeping" out of hot-mix asphalt concrete (HMAC) pavements, research was initiated on the permeability of coarse-graded Superpave mixes. Tests using a falling-head permeameter yielded inconsistencies in the relationship between air voids and permeability. It was hypothesized that the inconsistencies related to the inability of the permeability device and procedures to account for a compacted specimen's void characteristics: void size, arrangement, and interconnectivity. A testing apparatus and methodology, the void pathway test (VPT) was developed to describe such void characteristics. The VPT forces air (under pressure) through a HMAC specimen; a soap solution painted on specimen surfaces creates bubbles at exit points for the air flow. Void pathways and characteristics are related to the number and size of bubbles mapped on specimen surfaces. Results from 43 HMAC specimens indicated that significantly more void openings occur on perimeter surfaces than on cross-sectional surfaces. The majority of perimeter openings occurred within 25 mm of the cross-sectional surface through which air was input. No discernable pattern was evident in the number, arrangement, or interconnectivity of voids mapped on cross-sectional surfaces of a specimen. The results suggest that void pathways are not relatively straight and vertical but convoluted and that most tend toward the perimeter of a compacted specimen. These findings could significantly affect permeability testing using falling-head permeameters by challenging the basic assumptions relating to the flow necessary for using Darcy's law to calculate permeability.
总页数：	Transportation Research Record. 2001. (1767) pp40-47 (5 Phot., 3 Fig., 4 Tab., 11 Ref.)
报告类型：	科技报告