乳化沥青冷再生混合料的透水性与空隙特征

Permeability and air voids of cold recycled mixtures with asphalt emulsion

为了研究乳化沥青冷再生混合料的透水性与空隙特征之间关系,通过测定渗透系数来评价其透水性,并利用工业CT扫描观测其内部细观空隙结构.根据乳化沥青冷再生混合料养生过程中空隙率的变化,探究水泥和水对其空隙形成的影响.结果发现,乳化沥青冷再生混合料在较高的空隙率下具有相对较低的透水性;其平均空隙尺寸略小于同级配的热拌沥青混合料,且大空隙较少,小空隙较多;乳化沥青冷再生混合料的空隙由压实空隙和养生空隙构成,水分的蒸发和水泥用量对养生空隙的形成具有显著的影响,随着水分的蒸发和水泥的水化,乳化沥青冷再生混合料内部形成了许多养生空隙;乳化沥青冷再生混合料的空隙尺寸以及分布特征是造成其低透水性的重要因素.

The relationship between the permeability and air voids of cold recycled mixtures with asphalt emulsion was studied. The hydraulic conductivity was used to evaluate the permeability and the CT（ computed tomography） scanning was applied to find the characteristics of air voids. The effects of Portland cement and water were evaluated according to the change of air void content. The results showthat the cold recycled mixture has a relatively lowpermeability under a relatively high air void content. The average air void size of cold recycled mixture is a little smaller than that of hot mix asphalt mixture,with less air voids in large size and more air voids in small size. The air voids of cold recycled mixture are developed during compaction and curing time. In the process of curing,the evaporation of water and hydration of cement affect the air void content significantly leading to the formation of more air voids. The size and distribution of air voids are important factors that contribute to the relatively lowpermeability of cold recycled mixture.