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基于断裂力学理论,采用单边带裂缝梁三点弯曲试验,研究了沥灰比(沥青/水泥质量比mA/mC)对水泥乳化沥青(CA)砂浆断裂行为的影响。根据测试的荷载–扰度(P–d)和荷载–裂缝口张开位移(P–dc)曲线,计算了不同沥灰比CA砂浆的应力强度因子K_I、J积分和断裂能,并测试了CA砂浆的抗压及抗折强度。结果表明:随着沥灰比的增大,CA砂浆的强度降低但变形能力(延性)增大,CA砂浆由准脆性断裂过渡为韧性断裂;当m_A/m_C<0.5时,CA砂浆呈准脆性断裂,可用由线弹性断裂力学导出的断裂韧度K_(Ic)表征其断裂韧性;少量沥青的掺入虽使CA砂浆裂缝尖端塑性变大,但亦导致其强度降低,因而沥灰比为0.3时CA砂浆的K_(Ic)=0.248 5 MPa×m~(1/2),约为水泥砂浆的一半;当mA/mC≥0.5时,CA砂浆因塑性较大而呈韧性断裂,应用弹塑性断裂力学导出的J_(Ic)表征其韧性;沥灰比由0.5增大到0.9时,CA砂浆的JIc由39.222变为34.848 J/m~2,且因延性增大而使其断裂能由31.97增加到46.37 N/m;沥青相主要通过增大CA砂浆的延性而提高其韧性。
Based on the theory of fracture mechanics, the effect of asphalt mixture ratio (ratio of asphalt / cement ratio mA / mC) on the fracture behavior of cement emulsified asphalt (CA) mortar was studied by single point bending test. Based on the test load-disturbance (P-d) and load-crack opening displacement (P-dc) curves, the stress intensity factor K_I, J integral and fracture energy of different mortars and leachers were calculated and tested CA mortar compressive strength and bending strength. The results show that the strength of CA mortar decreases with the increase of asphalt mixture ratio, but the deformation capacity (ductility) of CA mortar increases. The transition from quasi-brittle fracture to ductile fracture of CA mortar. When m_A / m_C <0.5, The fracture toughness K_ (Ic) derived from the linear elastic fracture mechanics can be used to characterize the fracture toughness. Although the addition of a small amount of asphalt plasticizes the fracture tip of CA mortar, the fracture toughness decreases, When the mA / mC≥0.5, CA mortar due to plasticity and ductile fracture, the application of elasto-plasticity Fracture mechanics derived J_ (Ic) characterization of its toughness; asphalt ash ratio increased from 0.5 to 0.9, CA mortar JIc from 39.222 to 34.848 J / m ~ 2, and due to ductility increases its fracture energy from 31.97 To 46.37 N / m. Asphalt phase increases its ductility mainly by increasing the ductility of CA mortar.