Prediction of Carbonation on Precast Concrete Exposed to Severe Environmental Conditions

Abstract

The most external agents are chlorides that intrude into concrete and carbonation induced corrosion causing structural damage in marine environments. The carbonation induced corrosion occurred in marine concrete when carbon dioxide intrusion takes place into concrete cover and reaches the reinforcement causing corrosion in presence of moisture and oxygen. There are 3% CO₂ present in the atmosphere and some of the industrial belts, its concentration may be more. Therefore concrete structures are more or less affected by carbonation. The main reason for corrosion of reinforcement in concrete is only carbonation in presence of oxygen and moisture. The rate carbonation depends on the factors like relative humidity, concrete grade, concrete permeability, proactive work to concrete, cover depth and time. In this paper, the carbonation depth is determined for fourteen blended concrete mixes including control specimen with different replacement ratios of fly ash and silpozz cured in sea water after 28 days of normal water curing (NWC). The experimental results revealed that the 30% replacement of silpozz with ordinary Portland cement (OPC) combats carbonation in a better way exposed to saline environment.