The effect of formwork liner on the service life of self-compacting concrete

Abstract

The service life of any reinforced concrete is dependent upon the superior nature of concrete and its overall quality and excellence as a suitable cover material. Concrete acting as cover material is the only means by which destructive agents or other elements can access or infiltrate the structure resulting in corrosive damage to the rebar and causing other types of damage to occur. As a liner, the controlled permeable formwork (CPF) is an active technique that enhances concrete as a cover material. Moreover, this liner allows for air and water that is trapped inside to drain or spill out from the surface area of concrete whereas retaining small particles and cement. Accordingly, this not only minimises the porosity of the surface area of concrete, but it also helps towards improving or enriching the actual content. However, it also reduces the size and proportion of water to cement ratio (w/c). This paper aims to present the influence of CPF liner concerning the durability properties and the service life of reinforced/strengthened self-compacting concrete (SCC). To achieve this aim, concrete samples were cast in relation to the impermeable formwork (IMF) and CPF liner. A series of experimental tests were then conducted at different stages in order to examine accelerated rebar corrosion, rapid chloride penetration, chloride ingress, chloride diffusion. The findings from conducting the experimental investigations revealed that CPF concrete acquired excellent resistance against the ingress of chloride ions ranging between 54 and 75%. Furthermore, the results showed that the service life of self-compacting concrete cast against CPF liner was extended by around 1.5 times as compared to IMF concrete.