Factors Affecting Loss in Durability in Prestressed-Concrete Girders with Microcracking

Abstract

Early-age unexplained cracking in concrete structures is always a concern, as this signals the occurrence of uncontrolled volumetric changes. A study to investigate the effects of early-age microcracks on the service life of in-service prestressed-concrete girders was conducted. The temporal evolution of the cracks during a two-year period in 13 full-scale prestressed, precast girders was studied. Five of the girders were not subjected to external loads, whereas the remaining eight girders were in-service and under external loads. The results show that during the time frame considered, exposure conditions and the presence of pre-existing cracks had a more significant impact on the growth of microcracking than the effect of external loads, even when a protective coating was applied to the girder surfaces. Furthermore, the study showed that the temporal behavior of cracks can be better understood when both crack width and cracking density are taken into consideration.