Experimental Study on Deterioration Characteristics of Prestressed Concrete under the Coupling of Freeze–Thaw and Corrosion

In order to explore the deterioration characteristics of prestressed concrete under the coupling of freeze–thaw and corrosion, a series of aging tests and three-point bending tests was conducted. Furthermore, the deterioration process was analyzed at the meso-level with the help of computed tomography (CT) technology. The following conclusions can be drawn: (1) within a certain range, under the coupling effect, freeze–thaw and corrosion promote each other, and the degradation effect of the coupling test of freeze–thaw and corrosion is greater than the simple superposition of the two; (2) after the aging test, when the number of freeze–thaw cycles or the corrosion rate are higher, the cracking load and the ultimate load of the prestressed concrete are reduced, but the loss rate of the ultimate load is small; (3) the effective prestress of the aging specimen can be obtained according to the cracking moment, and the calculation formula is simplified according to the mechanical characteristics; and (4) under the coupling of freeze–thaw and corrosion, the size of the cracks and the number of the pores inside the specimen increase, whereas the number of pores in the volume range of 0.1–0.5 mm3 does not change significantly due to the filling effect of corrosion products.