Abstract
Abstract : In this paper, durability design parameters that are typically specified in structural design codes, were evaluated for their impacts on service lifespan. These parameters comprising concrete strength, cover depth, and cement type, were used as input variables into the new natural carbonation prediction (NCP) model. The resulting changes on the predicted lifespans were then evaluated. It was found that 10 MPa increment in concrete strength increases the structures lifespan geometrically 2.5 to 5.0 times. Similarly, 10 mm increment in cover extends the service lifespan 2.0 to 2.5 times. Also CEM II concretes with 10 MPa higher strength over that of CEM I concretes, gave the same carbonation resistance as the latter. Understanding of the impacts of durability design parameters aided by practical service life models, contributes towards a rational approach for service life design of concrete structures.