DIFFUSION TEST AS AN ALTERNATIVE INDICATOR FOR DURABILITY ASSESSMENT OF BITUMINOUS MIXTURES

• Main Author: KUSUMAWATI, AINE
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/1626
• Institution: Institut Teknologi Bandung

Diffusion Test is a new alternative test method under development for durability assessment of bituminous mixtures against water vapour. Water vapour in the pavement results from groundwater evaporation. If it is trapped within voids of the pavement, during cool weather it will condense in the form of water on the surface of aggregate particles. This process of vapour migration is utilised in this method. Two types of mixture were investigated, Hot Rolled Asphalt ( HRA) and Asphaltic Concrete ( AC). The Diffusion Test specimens were made at bitumen contents of respectively 50, 6o, 7%, 8%, 9% and also at optimum bitumen content for each type of mixture. Two specimens were prepared for each bitumen contents. The specimens then were conditioned in an oven of 35 °C, 45°C, and 50°C. Parameter used in this test to assess durability was a diffusion coefficient. The parameter was correlated to the Index of Retained Strength (IRS) as a common parameter to assess durability, obtained from the Marshall Immersion Test. In general, there is a relation between the Diffusion Test and the Marshall Immersion Test, i.e.the more bitumen in the mixture the smaller the diffusion coefficient, the greater the IRS, indicating a more durable mixture. Conversely, the less bitumen in the mixture the greater the diffusion coefficient, the smaller the IRS, indicating a less durable mixture. It must also be noted that there is a rather different trend between the diffusion coefficient and the IRS coming from differences between the nature of the two tests. The use of Diffusion Test shows a better result when comparing potential durability of a mixture relative to the other mixture. Marshall Immersion Test should be used instead of diffusion test to measure the potential durability of a mixture if only one type of mixture is being investigated.