紫外老化对温拌胶粉改性沥青砂浆开裂特性的影响

Effect of Ultraviolet Aging on Cracking Characteristics of Warm Mix Crumb Rubber Modified Asphalt Mortar

为研究紫外(UV)老化对温拌胶粉改性沥青砂浆(CR-WAM)开裂特性的影响,以SDYK表面活性剂型温拌胶粉改性沥青砂浆(CRS-WAM)、EM降黏剂型温拌胶粉改性沥青砂浆(CRE-WAM)及热拌胶粉改性沥青砂浆(CR-HAM)为研究对象,结合数字图像处理(DIC)技术、单边切口弯曲梁(SENB)试验与有限元方法,分析了UV老化时长对沥青砂浆开裂特性的影响.结果表明:UV老化后,沥青砂浆起裂点水平位移(U)和水平应变(EXX)、应力强度因子(K)及区域损伤因子(D)均增大,且随着UV老化时长的增加,其增长速率越来越快;CR-WAM的抗开裂、抗老化能力优于CR-HAM,CRS-WAM的抗开裂、抗老化能力最优,CRE-WAM次之;沥青砂浆的裂缝长度越长、越靠近跨中位置、倾斜角度越小,K值越大,应力集中越明显,越容易开裂.

In order to study the effect of ultraviolet(UV)aging on the cracking characteristics of warm mix crumb rubber modified asphalt mortar(CR-WAM),SDYK surfactant type warm mix crumb rubber modified asphalt mortar(CRS-WAM),EM viscosity reducer type warm mix crumb rubber modified asphalt mortar(CRE-WAM)and hot mix crumb rubber modified asphalt mortar(CR-HAM)were studied.The influence of UV aging time on the cracking characteristics of asphalt mortar was analyzed with the help of digital image correlation(DIC)technology,single-edge notch bending(SENB)test and finite element method.The results show that after UV aging,horizontal displacement(U)and horizontal strain(EXX)of cracking point of asphalt mortar,stress intensity factor(K)and regional damage factor(D)all increase,and with the increase of the time of UV aging,the growth rate is getting faster and faster.The anti-cracking and anti-aging ability of CR-WAM is better than that of CR-HAM.CRS-WAM has the best anti-cracking and anti-aging ability and followed by CRE-WAM.Crack length,crack inclination angle and crack position have great influence on K value.The longer the crack length,the closer to the midspan position,the smaller the tilt angle and the larger the K value is,the more obvious the stress concentration is,and the asphalt mortar is easier to crack.