Technical Effects of Air Cooled Blast Furnace Slag on Asphalt Mixtures

Air cooled blast furnace slag is a by product made of gradually air cooled molten blast furnace slag and is often stored in stockpiles near the iron mills and usually occupy a wide area around the iron mills. From this perspective the further use of these materials can have its own merits. Air cooled blast furnace slag can be used in asphalt mixtures because of their proper frictional properties. This research is conducted to investigate the effect of air cooled blast furnace slag on technical characteristics of asphalt mixtures and compare the results with the traditional asphalt mixtures. Two series of Marshal and Texas Boiling Tests were carried out in the laboratory. Three types of aggregates (air cooled blast furnace slag, siliceous gravel, lime gravel) with two types of dense graded and open graded were used. The frictional properties of the asphalt mixed with air cooled blast furnace slag materials were evaluated by using the British Pendulum, and the Sand Patch Method. Resistance to moisture was also determined in accordance to Texas Boiling Test. Results showed that by increasing percentage of air cooled blast furnace slag in asphalt mixtures, Marshall Stability, flexibility and skid resistance augmented. Also Texas Boiling Tests indicated that asphalt mixtures have a good resistance to stripping.