The fracture behaviour of cement bitumen emulsion mixture through the digital image correlation (DIC) method
Jian Ouyang, Wenting Yang, Peng Cao, Baoguo Han
Abstract
With the merits of low carbon emission and energy consumption, cement bitumen emulsion mixture (CBEM) is more and more preferred in the construction and rehabilitation of pavement engineering. However, CBEM has a high risk of cracking damage due to the inappropriate addition of cement. To deeply know and then reasonably design the cracking resistance of CBEM, the fracture behaviour of CBEM is studied by a semi-circular bending test, and the global displacement and strain of the specimen during the whole loading process are measured through digital image correlation (DIC). The results indicate that the three fracture stages of CBEM (i.e. crack initiation, crack propagation and failure) can be accurately identified by DIC data. The maximum value of the mean global horizontal strain, representing that the specimen affords the maximum tension energy, is proposed to identify the fracture failure point for the accurate calculation of fracture parameters. The fracture energy, J integral and fracture toughness of CBEM increase and then decrease with the increasing cement dosage. To obtain a good comprehensive fracture behaviour for CBEM, it is recommended that cement dosage can be between 2% and 3%, and the optimum cement dosage is 2.6%.