Download Free Follow Up Field Investigation Of The Effectiveness Of Antistripping Additives In Virginia Book in PDF and EPUB Free Download. You can read online Follow Up Field Investigation Of The Effectiveness Of Antistripping Additives In Virginia and write the review.

A previous field study of 12 pavements revealed considerable stripping in the surface layers of mixtures placed in 1991-92. Most of the mixes containing chemical additives showed visual stripping, but the ones containing hydrated lime did not show significant stripping. This study was a broad field survey with cores taken from each of the nine VDOT districts. The purpose was to get a better estimate of stripping in Virginia than that of the earlier study. Significant visual stripping was detected in many sites, which verified the fmdings of the earlier study. However, in this study, hydrated lime performed no better than chemical additives. The SM-2A 50-blow mixes with slightly more asphalt performed no better than the SM-2B or SM-2C 75-blow mixes. Pavement voids at many sites were too high for good durability, and the compaction and mix design specifications should be examined. The degree of stripping damage in underlying layers could influence performance at many sites.
This synthesis will be of interest to pavement designers, construction engineers, maintenance engineers, and others interested in avoiding or limiting moisture damage in asphalt concrete. Information is provided on physical and chemical explanations for moisture damage in asphalt concrete, along with a discussion of current practices and test methods for determining or reducing the susceptibility of various asphalt concrete components and mixtures to such damage. Moisture damage in asphalt concrete is a nationwide problem which often necessitates premature replacement of highway pavement surfaces. This report of the Transportation Research Board describes the underlying physical and chemical phenomena responsible for such damage. Current test methods used to determine the susceptibility of asphalt concretes, or their constituents, to moisture damage are described and evaluated. Additionally, current practices for minimizing the potential for moisture damage are examined.
An evaluation of the health effects and other relevant data since pub. of the 1977 NIOSH "Criteria for a Recommended Standard: Occupational Exposure to Asphalt Fumes." Includes an assessment of chemistry, health, and exposure data from studies in animals and humans exposed to raw asphalt, paving and roofing asphalt fume condensates, and asphalt-based paints. Will serve as to identify future research to reduce occupational exposures to asphalt. Chapters: no. of workers potentially exposed; physical and chemical properties; exposure; human health effects; experimental studies; research needs; uses and applications; summary of occupational exposure data; and respirators.