Assessment of moisture effect on open graded mixes using water sensitivity and Cántabro after immersion tests

Abstract

In Spain, water damage on the cohesion of porous asphalt (PA) and asphalt concrete for very thin layers (BBTM mixtures with a void content over 12%) was assessed using the Cántabro after immersion test (NLT-352). European Standards for bituminous mixtures (EN 13108) have gone into effect requiring us to assess water damage through Water Sensitivity testing (EN 12697-12). This represents an important change in how to evaluate PA and BBTM water resistance. Accordingly, new requirements must be set and included in the Spanish Highway Technical Specifications (PG-3). In order to assess and compare both methods, a series of bituminous mixtures have been prepared with several types of aggregates and fillers, and with different percentages of conventional and polymer modified bitumen. Both methods allow the assessment of water effect. Cántabro test is more sensitive for the evaluation of moisture damage on open bituminous mixtures. A significant correlation between Cántabro and sensitivity tests was found, allowing us to establish new specifications in line with the European Standards.