钢渣沥青混凝土耐久性室内试验研究

钢渣体积安定性不良且变异性大，当钢渣作为集料用于沥青混凝土时，存在体积稳定性不足和耐久性不明风险，长期服役过程中可产生体积膨胀甚至开裂，严重制约了其在道路建筑领域中的大规模应用。通过游离氧化钙含量、浸水膨胀率及集料压蒸试验检测了不同产地钢渣的体积稳定性，提出了钢渣集料体积安定性快速评价方法与控制指标。利用马歇尔试件和圆形切片试件的长期高温浸水试验分析了钢渣沥青混合料的体积稳定性能，并采用长期浸水后间接拉伸强度、回弹模量、疲劳寿命及车辙永久变形综合评价钢渣沥青混凝土力学性能的耐久性。结果表明：钢渣集料压蒸试验条件较为苛刻，可快速检测体积安定性，其胀裂粉化率宜不大于5%。在长期高温浸水条件下，沥青膜无法阻止水分侵入到钢渣集料内部，导致其沥青混凝土产生体积膨胀和性能衰减。钢渣沥青混凝土圆形切片试件能很好地反映出鼓包、裂纹的产生与演化过程。通过玄武岩沥青混凝土作为基准进行对比分析，提出了基于力学性能的钢渣沥青混凝土耐久性控制基准。

Laboratory evaluation on the durability of steel slag asphalt concrete

Steel slag has poor volume stability and high variability. When steel slag is used as aggregate in asphalt concrete, there is a risk of volume stability and durability. During long-term service, steel lag aggregate can cause volume expansion, which seriously restricts its application in road construction. The volume stability of steel slag obtained from different origins was tested by free calcium oxide content, immersion expansion rate and aggregate autoclave test. A rapid evaluation method and control index for the volume stability of steel slag aggregate were thus proposed. The volume stability of steel slag asphalt mixture was analyzed by long-term water immersion test of Marshall specimens and circular slice specimens. The indirect tensile strength, modulus, fatigue life and rutting permanent deformation after water immersion were used to evaluate the durability of steel slag asphalt mixture. The test results showed that aggregate autoclave test can be used a critical test method for quick detecting slag volume stability by controlling the conversion rate smaller than 5%. During the long-term water immersion, asphalt film cannot prevent moisture from invading into steel slag aggregates, resulting in the volume expansion and performance reduction of steel slag asphalt concrete. Circular slice test can well reflect the production and evolution process of bulge and crack within steel slag asphalt concrete. Through the comparative analysis of basalt asphalt concrete, the durability control benchmark of steel slag asphalt concrete was presented based on using mechanical properties.