Meso-scale damage characteristics of low carbon concrete with recycled aggregate based on in-situ CT test

Construction and industrial solid waste have caused some severe effects to the environment. The collaborative and effective disposals of these wastes not only have the positive impact on the usage of waste, but also could protect the environment. In this paper, low carbon concrete with recycled aggregate (LCCRA) mainly made of phosphogypsum-based cementitious material and recycled aggregate is studied. Uniaxial compression test was used to investigate the basic mechanical properties of LCCRA. In-situ computerized tomography (CT) and digital volume correlation (DVC) were used to investigate meso-scale damage characteristics of LCCRA under uniaxial compression. The results demonstrated that this concrete has a higher compressive strength than the ordinary recycled aggregate concrete (ORAC). Gray mean value and gray distribution variance from CT gray scale image can characterize the meso-scale damage process of LCCRA. Interfacial transition zone (ITZ) is the main factor that affects the meso-scale damage characteristics, which could be revealed by the in-situ CT test and DVC method.