This report documents the three-year evaluation of a slurry seal study undertaken as part of FHWA Demonstration Project No. 55, "Asphalt Emulsions for Highway Construction". The objective of this study was to collect information on the design, construction, and performance of a two-course asphalt emulsion slurry seal for mainline surface treatment. The study evaluates the potential extension of useful pavement life of the existing pavement and the adequacy of skid resistance of that material for a three-year period on mainline, moderately traveled bituminous pavements. Sites on Route U.S. 206, Burlington County and Route 1-78, Somerset County were selected for slurry seal applications. A two-course slurry seal of top course (blast furnace slag) and bottom course (3/8 Inch stone) was applied to a one and one-half mile section of Route U.S. 206 and two-one m11e sections of Route 1-78. The slurry seal application extended the useful pavement life of both sites by three to four years and provided good skid resistance for the period of evaluation. The slurry seal 1s a viable alternative for temporary surface Improvement on moderately traveled highways. Blast furnace slag aggregate should be used in the surface course of slurry seals. The slurry seal aggregate should be plant-mixed to uniformly blend the coarse and fine gradations. The spreader box should be equipped with stabilizer bars and an auger to uniformly distribute the slurry seal across the roadway.