Durability of reactive powder concrete containing mineral admixtures in seawater erosion environment

The macro-performance, microstructure, and composition of reactive powder concrete (RPC) with mineral admixture in a marine erosion environment were investigated by tests. The effects of fly ash (FA) and ground granulated blast-furnace slag (GGBS) content on the seawater corrosion resistance of RPC were evaluated, and the mass and compressive strength loss models of RPC with mineral admixture corroded by seawater were established. The results showed the strength of RPC was changed by the formation of single and compound salts under the action of seawater erosion: the gel pores decreased and the harmful pores increased with the increase in wet-dry cycle times. The addition of FA and GGBS can significantly improve the seawater erosion resistance of RPC, and GGBS has a more significant effect than FA on improving the seawater erosion resistance of RPC in the later period. Compared with RPC-mixed single FA or GGBS, the microstructure and macroscopic properties of RPC containing hybrid FA and GGBS are better. The reasonable compound addition of FA and GGBS can allow the "superposition effect" to take place, reduce the hydrated calcium hydroxide content, and improve the matrix compactness, thereby improving the macroscopic properties of RPC. Considering workability, strength, durability, economy, and environmental protection, the F20G20 mixture is recommended.