Study on Mass and Performance Deterioration of Concrete Under Multiple Corrosive Environments

This study investigates the corrosion behavior, mass changes, and relative dynamic elastic modulus variations of PC (Portland cement concrete) and G60 (with 60% slag) under two treatment methods: immersion in 3.5% NaCl solution and composite (3.5% NaCl + 5.7% Na₂SO₄) solution, as well as dry-wet cycles. Results indicate that under water and NaCl conditions, no significant mass loss or modulus reduction occurred, with only minor surface efflorescence. However, in the composite solution, severe spalling was observed, with mass loss reaching approximately 1.4% and the relative dynamic modulus decreasing to around 90% after 540 days. Dry-wet cycling accelerated the corrosion process compared to immersion, leading to greater mass loss and modulus reduction. The incorporation of slag improved resistance to ionic penetration in both chemical corrosion and salt crystallization, though this effect diminished with prolonged exposure or increased cycling.