NOVEL METHODS FOR IN SITU TESTING AND MONITORING OF THE DURABILITY OF REINFORCED CONCRETE STRUCTURES

摘要

Corrosion of steel in reinforced concrete due to carbonation and chloride ingress isone of the principal causes of deterioration of reinforced concrete structures. It is widelyrecognised that the concrete cover provides protection to the reinforcement against bothcarbonation and chloride ingress,which in turn depends on its permeation characteristics.Therefore,a measure of the transport properties of the concrete cover is important forassessing the durability of reinforced concrete. On the other hand,measurement of the rate ofcarbonation and the advance of the chloride front is essential to predict the service life ofreinforced concrete structures. That is,methods which can be used to monitor the effect ofcarbonation and chloride ingress would be required. In this paper,two in situ permeabilityapparatus,viz. Autoclam Permeability System (for measuring gas/water permeability andwater absorption) and Permit Ion Migration Test (for determining the ionic diffusion) aredescribed. These instruments can be mounted on the concrete surface for carrying out thetests. Some typical results are presented for these two novel testing systems to illustrate theirusefulness for the condition assessment of reinforced concrete structures. In addition,thedevelopment of fibre optic sensor systems for monitoring the pH of concrete is described.