A TECHNOLOGICAL MODEL FOR PREDICTING REBAR CORROSION PRODUCED BY COVERCRETE CARBONATION

In this paper a simple technological model is developed for the service life prediction of reinforced concrete structures built in the local environment with rural and urban characteristics. The model contemplates the steel corrosion produced by covercrete carbonation. It was developed starting from the report of structures in service. The obtained prediction model correlates the parameters that characterise the covercrete with useful service life. The structures evaluated (bridges, buildings and ducts) are placed in the Province of Buenos Aires, Argentina, whose environment is representative of an area of 570000 km. The structures have an age that varies between 15 and 60 years. Many of these have rebar corrosion induced by covercrete carbonation. The behaviour of structures in service is analysed in relation to different parameters linked with the quality of covercrete, such as effective porosity, density, coefficient of capillary absorption and carbonation depth. Simultaneously, concrete mixes were prepared in the laboratory and the covercrete parameters were determined. These mixes cover a wide range of water/cement ratios and compression strength, including those corresponding to the structures in service evaluated. These values were applied to the prediction model and the results obtained are compared with the effective performance of the evaluated structures. It is observed that the detected parameters match the behaviour in service and the history of the structure. Therefore, they are useful for durability design.

• INTRODUCTION

• EVALUATION OF CONCRETE STRUCTURES IN SERVICE

• TEST RESULTS AND CALIBRATION OF THE PREDICTION MODEL

• CONCRETE MIXES PREPARED IN THE LABORATORY. ANALYSIS OF THEIR COMPLIANCE WITH RESPECT TO THE PREDICTION MODEL

• CONCLUSIONS

• ACKNOWLEDGEMENTS

• REFERENCES