Influence of ageing on high content polymer modified asphalt mixture stripping, cracking and rutting performances

Abstract

The outstanding properties of High Content Polymer Modified Asphalt (HCPMA) have been widely recognised, but there are only scattered studies have investigated the influence of ageing on HCPMA properties, and even fewer researches have discussed this at the mixture level. This study seeks to evaluate the HCPMA mixture performance with the influence of ageing taken into consideration. Mixture stripping, cracking and rutting resistances were evaluated by the means of Cantabro loss test, Semi-Circular Bend (SCB) test and Hamburg Wheel-Tracking (HWT) test, respectively. Both laboratory short-term ageing and long-term ageing were conducted and different ageing durations/temperatures were investigated. Results indicated that an unaged HCPMA mixture (7.5% SBS) has much improved overall performance over conventional modified mixture (4.5% SBS). However, it is also more ageing susceptible. All three types of performances evaluated in this study were negatively influenced by ageing. Stripping and rutting resistance were more sensitive to higher ageing temperatures while cracking resistance was sensitive to both higher ageing temperatures and longer ageing duration. Mixture rutting performance after ageing is seldom considered as a critical performance. However, in the case of HCPMA mixture, it may need extra attention and related specification should be developed. Moreover, binders extracted from the aged mixtures were examined and the results well agreed with the mixture ageing behavior except for the inconsistency between the 210°C_2 h aged mixture’s deepest rutting depth and its smallest Jnr3.2 value, which pointed out the possibility that Jnr3.2 parameter from MSCR may overestimate the contribution of binder elasticity on mixture rutting resistance.

Keywords:

• HCPMA
• SBS polymer
• laboratory ageing
• stripping resistance
• cracking resistance
• rutting resistance

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 51778481].