Long term effectiveness of anti-stripping agents

• Zycosoil improves long term performance compared with the hydrated lime.
• The most significant factor affecting the TSR is the bitumen content.
• The proposed model can be employed to find the proper time for rehabilitation.

Numerous factors affect long term resistance of asphalt mixtures against stripping, therefore, proposing a mathematical model between the stripping failure and these factors is essential. The rehabilitation time of pavements, a very pivotal issue, can be predicted if the developed model comprises time as an independent factor. Apart from the capability of such model for prediction of rehabilitation time, the proposed model reveals the effect of each individual factor on the stripping process and it discloses the interrelationship between the pertinent factors. In this study, Response Surface Methodology (RSM) was successfully employed to establish the time dependent models between Tensile Strength Ratio (TSR) as the response parameter and independent factors such as time and anti-stripping additives (namely hydrated lime and Zycosoil). The results obtained through the modeling showed that both the short and long term performance of the Zycosoil is superior to the hydrated lime. The proposed models can be solved to find the time that asphalt mixtures take to reach certain terminal TSR; e.g. for TSR = 80. A mathematical model is developed that can predict the proper time of rehabilitation of pavement before stripping failure.