The present investigation aimed at evaluating the permanent deformation responses of bitumens modified with low-density polyethylene - either with or without polyphosphoric acid (bitumen+PE and bitumen+PE+PPA) - and by considering bitumen tests (MSCR – multiple stress creep and recovery), rheological models and asphalt tests (FN – flow number). The formulations were graded as PG 76-xx and the standardised MSCR tests were conducted at 64, 70 and 76°C. The bitumen+PE+PPA showed a higher resistance to permanent deformation than the bitumen+PE according to MSCR and FN tests in a general context, even though none of the formulations may be assumed as overly stress sensitive (Superpave® parameter lower than 75% in all cases), neither they depicted high levels of elasticity due to their small per cent recoveries (all lower than 25%). It was also hypothesised that the contributions of PE and PPA on the increases in the stiffness of the bitumen+PE+PPA were made individually.

本研究旨在评估用低密度聚乙烯改性的沥青的永久变形响应 - 有或没有多磷酸（沥青 + PE 和沥青 + PE + PPA） - 并通过考虑沥青测试（MSCR - 多应力蠕变和恢复)、流变模型和沥青测试（FN – 流数）。配方分级为 PG 76-xx，标准化 MSCR 测试在 64、70 和 76°C 下进行。根据 MSCR 和 FN 测试，在一般情况下，沥青 +PE+PPA 显示出比沥青 +PE 更高的永久变形抗力，即使没有一种配方可能被认为对应力过于敏感（Superpave® 参数低于 75%在所有情况下），由于回收率很小（均低于 25%），因此它们都没有描绘出高水平的弹性。