A review of new methods for measuring saturation of concrete and its impact on concrete properties

Abstract

Most durability problems with cement-based materials (CBMs) are water related, and CBMs are rarely fully water saturated in service. Therefore, methods for non-destructive testing (NDT) of the degree of saturation (DOS) in CBMs and the effect of DOS on durability have received increasing attention from researchers in recent years. This paper reviews the testing principles, methods and applications of five NDT methods (LF-NMR, NR, EIT, GPR and TDR) for the DOS measurement in CBMs. Solutions to challenging problems in the testing process are provided, the advantages and disadvantages of these methods are compared, and their prospects for engineering applications are evaluated. Next, the effects of DOS on the mechanical properties, transport properties and frost resistance in CBMs are further analyzed. The results show that LF-NMR and NR are suitable for scientific research applications, GPR and TDR for engineering applications, and EIT for both. As DOS increases, the elastic modulus of CBMs increases and the compressive strength decreases. The point of abrupt change in the material properties with DOS curve corresponds to its own critical DOS (DOSCR). The DOSCR for transport properties is approximately 60 %, while for frost resistance in the range of 48–90 %. The DOSCR will be significant to study the durability and predict the service life in CBMs.