Characteristics of the alkali-silica reaction in seawater and sea sand concrete with different water-cement ratios

Research of seawater and sea sand concrete (SWSSC) is the current hot topic, but effects of water-cement ratios (W/C) on alkali-silica reaction (ASR) of SWSSC haven't been investigated. To solve this issue, the ASR products, pore structure and expansion rate of specimens with different W/C (0.35 similar to 0.55) were measured. The study shows that pore structure and Na+ consumption are two key factors influencing ASR of SWSSC. When the W/C increases from 0.45 to 0.55, Na+ in specimen replaces K+ in ASR-P1(K0.52Ca1.16Si4O8(OH)(2.84)center dot 1.5H(2)O), and ASR-P1 is converted into Na-shlykovite(NaCaSi4O8(OH)(3)center dot 2.3H(2)O); the porosity is the dominant factor for the expansion rate of SWSSC. When the W/C increases from 0.35 to 0.45, the Na+ consumption is the dominant factor for the expansion rate of SWSSC. Magnesium element mainly coexists in Na-shlykovite and transition zone in SWSSC with W/C = 0.55. The research results are beneficial to inhibit ASR of SWSSC with different W/C and improve their durability.