Study on the mechanical properties of self-compacting recycled aggregate concrete using CFB slag as fine aggregate

To reveal the influence of CFB slag on the mechanical and expansion properties of self-compacting recycled aggregate concrete (SCRAC), five SCRACs with different CFB slag replacement amounts were made, the cubic compressive strength test, the splitting tensile strength test, the axial compressive strength test, and the dry shrinkage test were carried out. The failure processes and failure forms of SCRAC under compression and tension were observed. The effects of the influence of the CFB slag replacement rate on the basic mechanical properties of SCRAC were analyzed. The conversion relationship between various mechanical indicators of SCRACs was explored. The drying shrinkage performance of SCRAC was tested using the grey theory. The test results indicate that the compressive failure of SCRAC using CFB slag as fine aggregate is similar to that of SCC. The results show that the cubic compressive strength, splitting tensile strength, and axial compressive strength of self-compacting recycled concrete are the highest when the sand replacement ratio of CFB slag is 10%. The proposed conversion relationship between the cubic compressive strength of SCRAC and other mechanical properties indexes has high accuracy. GM (1, N) model and grey correlation analysis were established to analyze the influencing factors of drying shrinkage of SCRAC. The drying shrinkage deformation of SCRAC using CFB slag as fine aggregate has a hyperbola relationship with time, and a lower CFB slag sand replacement rate can compensate for the shrinkage of SCRAC.