Durability characteristics and quantification of ultra-high strength alkali-activated concrete. (November 2022)

• Record Type: Journal Article
• Authors: Cai, Rongjin; Tian, Zushi; Ye, Hailong
• Is Part Of: Cement & concrete composites. Volume 134(2022)
• Publication Date: 2022-11
• Subjects: Alkali-activated binder -- Ultra-high strength concrete -- Durability -- Corrosion of steel; Composite-reinforced concrete -- Periodicals; Concrete -- Periodicals; Composite materials -- Periodicals; Composites de ciment -- Périodiques; Béton -- Périodiques; Composites -- Périodiques; Béton léger -- Périodiques; Cement composites; Composite materials; Composite-reinforced concrete; Concrete; Lightweight concrete; Periodicals; Electronic journals; 620.135
• DOI: 10.1016/j.cemconcomp.2022.104743
• Languages: English
• ISSNs: 0958-9465

Abstract

Abstract: Clinkerless ultra-high strength concrete formulated using alkali-activated binders (AAB-UHSC) emerges as a green high-performance construction material, but its durability characteristics have not been systematically investigated yet. In this work, the resistances of AAB-UHSC against water absorption, carbonation, chloride diffusion, and chloride-induced electrochemical corrosion of steel, are quantitatively evaluated and compared with those of ordinary Portland cement (OPC)-based UHSC and normal-strength AAB (AAB-NSC) counterparts. The results show that in comparison with OPC-UHSC of similar strength of ∼150 MPa, AAB-UHSC has lower water-permeable porosity and demonstrates superior performance against water absorption and chloride ingress, but a weaker carbonation resistance. However, despite lower CO2 uptake capacity, the carbonation resistance of AAB-UHSC is about six times stronger than that of AAB-NSC, owing to its highly densified microstructure. Under the same chloride level and relative humidity conditions, the corrosion rate of steel embedded in AAB-UHSC is higher than that in OPC-UHSC, likely due to its higher moisture content and [Cl − ]/[OH − ] ratio that expedite steel dissolution. Moreover, the incorporation of steel fibers has limited influence on the transport-related durability performance of AAB-UHSC, implying a densified interfacial zone between steel fibers and AAB-UHSC matrices.