New procedure to control the tack coat applied between bituminous pavement layers

• We analyze the already established methods to control tack coat dosage on site.
• We design and develop a new device and the procedure needed to accurately control the dosage on site.
• We develop tests to check the proper behaviour of the device.
• We analyze and correlate different factors related to the results obtained from the tests.

To achieve proper bonding between the pavement layers it is necessary to spread the precise amount of tack coat. In several laboratory tests, effectiveness of a newly designed device to control the tack coat dosage applied on site is studied, in which the most influential variables are surface macro-texture and amount of tack coat applied, with a negligible influence of the emulsion type. According to the results obtained, the geotextile absorbs higher percentages of emulsion for samples of bituminous mixtures with lower surface macro-texture values, e.g. AC16D, while the lowest percentages of absorbed emulsion are obtained for samples with higher surface macro-texture values, e.g. BBTM11A. The emulsion percentage absorbed by the geotextile is directly related with the quantity of emulsion in charge of the bond between layers.