Sulfonated asphalt and natural rock asphalt were used to toughen oil well cement paste (OWCP). The difference of micro-morphology, surface functional groups and heat resistance of two kinds of asphalt was studied. Rock asphalt was treated by low-temperature plasma, and the mechanism of improving hydrophilicity was further analyzed and explained. The toughness of cement-based composites with asphalt was analyzed from triaxial stress-strain curves. Interface characteristics between sulfonated asphalt or rock asphalt and cement paste were gained. The crack propagation in cement paste was discussed systematically by using SEM microscopic observation. The results show that the thermal stability of the rock asphalt is higher than that of the sulfonated asphalt. XPS analysis results show that oxygen-containing functional groups, such as C–OH, CO, and C–O appear on the surface of rock asphalt treated by oxygen plasma. The surface free energy of plasma-treated rock asphalt was increased from 27.05 mJ·m⁻² to 53.29 mJ·m⁻², which indicates the improvement of hydrophilicity of the surface of rock asphalt. Triaxial stress-strain curve analysis results show that 3% content of sulfonated asphalt and treated rock asphalt can improve the toughness of oil well cement paste. A good interfacial transition zone with few micropores is found between the cement hydration products and sulfonated asphalt or treated rock asphalt by using SEM microscopic observation. SEM observation of crack propagation behavior in cement-based composites with asphalt indicated that sulfonated asphalt and plasma-treated rock asphalt improved the toughness of oil well cement by deflecting, bending and bridging the cracks.

磺化沥青和天然岩石沥青用于增韧油井水泥浆（OWCP）。研究了两种沥青的微观形貌，表面官能团和耐热性的差异。用低温等离子体处理岩沥青，并进一步分析和解释了提高亲水性的机理。从三轴应力-应变曲线分析了沥青基水泥基复合材料的韧性。获得了磺化沥青或岩石沥青与水泥浆之间的界面特性。利用SEM显微镜观察系统地讨论了水泥浆中的裂纹扩展。结果表明，岩石沥青的热稳定性高于磺化沥青。XPS分析结果表明，含氧官能团（例如C–OH，CO和C–O出现在经过氧等离子体处理的岩石沥青表面上。等离子处理过的岩石沥青的表面自由能从27.05 mJ·m ^-2增加到53.29 mJ·m ^-2，表明岩石沥青表面的亲水性有所提高。三轴应力-应变曲线分析结果表明，磺化沥青和处理后的岩石沥青含量为3％可以提高油井水泥浆的韧性。利用SEM显微镜观察，在水泥水合产物与磺化沥青或处理过的岩石沥青之间发现了一个良好的界面过渡区，几乎没有微孔。SEM对沥青基水泥基复合材料中裂纹扩展行为的观察表明，磺化沥青和等离子处理的岩石沥青可通过偏转，弯曲和桥接裂缝来提高油井水泥的韧性。