This six-year study addressed the question, "Are spray applied fog and rejuvenator treatments effective and safe?" The project included a survey of US state highway departments and industry experts, repeated field trials evaluating commercial products on different surface types in different climates and traffic situations, and evaluation of several test methods, including permeability, friction, surface texture, spectral wave analysis, and chemical and rheological properties. The study found the treatments to be generally inexpensive and effective in providing protection to pavement surfaces and prolonging pavement life. The primary constraint on dense-graded surfaces is friction loss. Sanding and strict traffic control until friction returns to a specified level mitigates the problem. The portable dynamic friction tester and circular texture meters are useful for quick and repeatable field friction testing. A relatively inexpensive low-temperature mixture test on field cores using the bending beam rheometer determines the brittleness of aging dense pavement surfaces. Other test methods gave mixed results. Visual observations showed the treatments prevented surface water intrusion up to four years after application. The treatments also significantly prolonged the life of chip seals, open-graded mixes and shoulders. (a) For the covering entry of this conference, please see ITRD abstract no. E217100.
Samenvatting