ABSTRACT

Coarse recycled concrete aggregates (CRCAs) were used as substitutes in asphalt mixtures. These aggregates have a layer of porous cement mortar on their surfaces that impairs their physical and mechanical properties. Therefore, their surfaces were coated with waste plastic bottles to improve their quality. Fatigue cracking, as a critical failure, in asphalt mixtures containing 0, 15, 30, and 50% coarse recycled concrete aggregate was evaluated using the indirect tensile fatigue test in wet and dry conditions. Also, the adhesion of mixture ingredients (bitumen and aggregates) to each other was determined using the sessile drop test based on the surface free energy concept. According to the results, the asphalt mixes containing CRCA had a higher optimum bitumen content compared to the control mixture. The modified asphalt mixtures had a shorter fatigue life in wet and dry conditions. Furthermore, moisture reduced the fatigue resistance of the control and modified asphalt mixtures, and this rate of decline was greater in the mixtures containing CRCA due to their high absorption.

摘要

粗再生混凝土骨料（CRCA）被用作沥青混合料的替代品。这些骨料的表面上有一层多孔水泥砂浆，损害了它们的物理和机械性能。因此，它们的表面涂有废塑料瓶以提高质量。使用间接拉伸疲劳试验，在潮湿和干燥条件下，评估了含有0％，15％，30％和50％的粗再生混凝土骨料的沥青混合料的疲劳破裂，这是一种严重的破坏。另外，使用基于表面自由能概念的无滴试验确定混合物成分（沥青和骨料）彼此之间的粘附力。根据结果​​，与对照混合物相比，含CRCA的沥青混合物具有更高的最佳沥青含量。改性沥青混合物在干湿条件下的疲劳寿命较短。此外，水分降低了对照沥青和改性沥青混合物的抗疲劳性，并且由于包含CRCA的混合物具有高吸收性，因此这种下降速度更大。