Effects of asphalt content and reclaimed asphalt pavement on the performance of cold mix asphalt

  • Magdalene Nafula Otieno SMARTEC, JKUAT. P. O. BOX 62000 - 00200, Nairobi.
  • James Wambua Kaluli
  • Charles Karimi Kabubo

Abstract

The use of Cold Mix Asphalt (CMA) for road pavement is a technique that batches, mixes, lays and compacts asphalt concrete at ambient temperatures. The application of CMA for road pavement is still limited especially in developing nations like Kenya. This is due to lack of universal standards required for the design and evaluation of cold mix asphalt. Asphalt content and type of aggregates significantly contribute to the performance of CMA. This study assessed the effects of asphalt content and recycled aggregates from Reclaimed Asphalt Pavement (RAP) on the performance of CMA. Modified Marshall Method was used to prepare two sets of specimens at varying binder content: one composed of virgin aggregates (virgin mix) and the other a mixture of virgin and RAP aggregates (RAP mix). Specimens were cured in three stages: mould curing for 24 hours at room temperature, isothermal curing in the oven at 400C for 72 hours and air curing at room temperature for 3 hours. The performance of CMA was analyzed in terms of stiffness, resistance to moisture damage and porosity. At varying asphalt content, the average RAP mix stiffness was approximately 26% higher than that of the virgin mix. Moreover, the use of recycled aggregates from RAP improved the resistance of CMA to moisture damage by reducing stability loss to 28%, increasing the TSR values above 0.7 and reducing the amount of absorbed moisture to 0.06%. Recycling of RAP produced a mix with porosity higher than 10% that has negative effects on the durability of CMA pavements. In conclusion, Asphalt content beyond 3% decreases the stiffness of CMA hence it is not recommended for production of CMA pavements. Recycling of RAP aggregates is recommended as it improves the performance of CMA pavements in terms of stiffness and resistance to moisture damage.
Published
Jul 17, 2019
How to Cite
OTIENO, Magdalene Nafula; KALULI, James Wambua; KABUBO, Charles Karimi. Effects of asphalt content and reclaimed asphalt pavement on the performance of cold mix asphalt. JOURNAL OF SUSTAINABLE RESEARCH IN ENGINEERING, [S.l.], v. 5, n. 1, p. 1-11, july 2019. ISSN 2409-1243. Available at: <http://sri.jkuat.ac.ke/ojs/index.php/sri/article/view/721>. Date accessed: 21 oct. 2019.