考虑第二次压密的乳化沥青冷再生混合料室内试验方法研究

Study of the Emulsified Asphalt Cold Recycled Mixture Experiment Methods Considering the Secondary Compaction Process

冷再生沥青混合料在常温下摊铺和碾压，空隙率较大，性能方面不能达到热拌沥青混合料（HMA）的标准，一般被用在路面结构中的基层或下面层中，其上还须加铺一定厚度的HMA以满足道路使用的要求。在冷再生层上摊铺HMA时，HMA高达150～170℃的高温，会将冷再生层加热，加之施工机械和车辆荷载等作用，致使冷再生层会被进一步压实，称之为冷再生层的“第2次压实”过程。对现场冷再生层钻芯取样后发现，摊铺HMA前后的冷再生芯样的空隙率相差可达3％。现有冷再生混合料设计方法对这一现象并未考虑，导致冷再生层在实际施工过程中出现了严重的压密性车辙。提出在进行冷再生混合料设计时，应该考虑不同施工季节以及第2次压密过程的影响，并对现有试验方法进行了必要的改进。

Cold recycled mixture is usually used as base or under surface layer, and it＇s necessa- ry to cover HMA of a certain thickness. During the construction of HMA on the cold recycled layer, the temperature of HMA can reach 150 - 170 ℃, so the cold recycled layer will be heated by the HMA. In addition to construction machinery and vehicles, the cold recycled layer will be compacted again. We call this process ＂the secondary compaction＂ process. By drilling the core of cold recycled mixture, we can find that before and after the HMA paving, the difference of the air void of cold recycled mixture can reach 3%. Existing cold recycled mixture design method does not take on this phenomenon, leading to a serious rut of compaction in the construction process of HMA on the cold recycled layer. The purpose of this paper is to elaborate on this phenomenon and suggest considering ＂ the secondary compaction＂ process when we design the cold recycled mixture, and made some suggestions to improve the existing cold recycled mixture design method.