Evaluation on Moisture Susceptibility of Warm Mix Asphalt

• Main Authors: Sze-Wen Yeh, 葉斯文
• Other Authors: 劉明仁
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/91959353553906492742

碩士 === 淡江大學 === 土木工程學系碩士班 === 96 === Nowadays the price of crude oil and fuels are getting costly every day. Global warming and greenhouse effect have become important issues in pavement engineering research and development. Warm mix asphalt (WMA) is a new technology that uses lower mixing and compacting temperatures for the production of asphalt mixtures. WMA, therefore, have benefits of environmental protection, saving energy resources, and good workability. Moisture susceptibility of WMA, however, may be a crucial problem due to not completely dried aggregates resulting from its lower mixing temperature, especially in Taiwan’s hot and humid environment. This study investigated the potential of moisture damage of WMA which contained Sasobit® as an additive, and the effectiveness of hydrated lime and portland cement for reducing moisture susceptibility of WMA. Based on the results of several stripping tests, the major conclusions of this study were summarized as follows: 1.Viscosity test results showed that WMA containing Sasobit® had decreased viscosity at higher temperature, and increased viscosity at lower temperature. The reductions of mixing temperature were 11℃ and 14℃ with the addition of 2% and 3% Sasobit®, respectively. 2.Laboratory stripping test results (except boiling test) showed that WMA with 2% and 3% Sasobit® generally performed better than HMA in stripping resistance. The reason why WMA showed worse performance than the HMA did in the boiling test, however, was possibly related to the thermal behavior of Sasobit® and the nature of the boiling test at high temperature. 3.Laboratory stripping test results showed that addition of hydrated lime and portland cement to WMA substantially increased its stripping resistance. Hydrated lime performed better than portland cement did in all stripping tests. 4.Two methods of introducing hydrated lime, dry mixing and wet mixing, were examined. Results of AASHTO T283 test showed that WMA using wet mixing (aggregates coated and dried with lime slurry in advance) performed better than WMA using dry mixing.