This article demonstrates the need to laboratory condition asphalt mixtures to simulate combined environmental effects and then to test unconditioned and conditioned specimens in a manner that damage from these environmental effects can be accumulated. The current state-of-the-art for evaluating asphalt mixtures for use on projects relies on either single-mechanism laboratory conditioning such as oxidation in AASHTO R30, or test methods that cannot accumulate combined effects such as indirect tensile strength in AASHTO T283. This article evaluated hundreds of laboratory-conditioned and field-aged specimens in a hot and no-freeze climate to demonstrate a laboratory conditioning protocol that was able to simulate at least 4 years of field aging, whereas conventional single-mechanism protocols were not. Temperature and moisture conditions within asphalt mixtures were measured over time and used as part of the assessment. The conditioning protocol that showed the most promise consisted of combined exposure to oxidation, moisture, and freeze–thaw mechanisms. The specific combined-effects conditioning protocol used here was 5 days of oxidation at 85°C, 14 days of moisture while submerged in 64°C water, and one freeze–thaw cycle. Other combined-effects protocols could be more suitable for other environments or situations; the main point of this article is that inclusion of oxidation, moisture, and freeze–thaw conditioning into one protocol is promising. The environmental conditions and mechanical property test data presented here suggest the asphalt industry needs to be harsher on mixes during laboratory evaluations, and that combined environmental effects conditioning should be given implementation consideration.

本文表明，需要对沥青混合料进行实验室条件模拟，以模拟综合的环境影响，然后以可以累积这些环境影响造成的损害的方式测试未处理的和已处理的标本。当前评估项目中使用的沥青混合物的最新技术依赖于单一机理的实验室条件，例如AASHTO R30中的氧化，或无法累积综合效应（例如AASHTO T283中的间接拉伸强度）的测试方法。本文评估了在高温和非冻结气候下的数百个经过实验室条件和现场老化的标本，以证明能够模拟至少4年现场老化的实验室条件协议，而传统的单机制协议则无法。随时间测量沥青混合物中的温度和湿度条件，并将其用作评估的一部分。表现出最大希望的调节方案包括氧化，湿气和冻融机制的综合暴露。这里使用的特定的综合效果调节方案是在85°C的温度下氧化5天，浸入64°C的水中14天的水分，以及一个冻融循环。其他组合效果协议可能更适合其他环境或情况；本文的重点是将氧化，水分和冻融条件纳入一项协议是有希望的。此处提供的环境条件和力学性能测试数据表明，在实验室评估期间，沥青行业需要对混合料更加苛刻，