Influence of Controlled Permeable Formwork Liner on the Service Life of Reinforced Concrete

The service life of RC 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 a structure, resulting in corrosive damage to rebar and causing other types of damage. 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 concrete’s surface while retaining small particles and cement. Accordingly, this not only minimizes the porosity of the surface area of concrete, but it also helps to improve or enrich the actual content. However, it also reduces the size and proportion of the water-to-cement ratio (w/c). This paper aims to demonstrate the effect of CPF liner with respect to the durability properties and service life of reinforced/strengthened concrete. To this end, concrete samples were cast in relation to the impermeable formwork (IMF) and CPF liner using three (3) w/c ratios—0.48, 0.41, and 0.31. Experimental tests were then conducted at different stages to determine rapid chloride penetration, chloride ingress, chloride diffusion, and accelerated rebar corrosion. The findings from the experimental investigations revealed that CPF concrete acquired excellent resistance against the ingress of chloride ions ranging between 47% and 80%. Furthermore, the results showed that the service life of concrete cast against CPF liner was extended by around 2.1 times compared to IMF concrete.