Durability of internally cured concrete with silicon–aluminum based fine lightweight aggregate exposed to combined sulfate and wetting–drying attack

• Published in: Materials and structures Vol. 56; no. 10
• Main Authors: Zhang, Yating, Lin, Jiaheng, Fan, Ziwei, Zhu, Xingyi
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.12.2023; Springer Nature B.V
• Subjects: Aluminum; Blast furnace slags; Building construction; Building Materials; Civil Engineering; Drying; Durability; Engineering; Flexural strength; Fly ash; Lightweight; Machines; Manufacturing; Materials Science; Microstructure; Modulus of elasticity; Original Article; Processes; Silicon; Solid Mechanics; Sulfate resistance; Theoretical and Applied Mechanics; Wetting; Durability; Silicon–aluminum based fine lightweight aggregate; Internally cured concrete; Wetting–drying protocols; Sulfate attack
• ISSN: 1359-5997; 1871-6873
• DOI: 10.1617/s11527-023-02261-2

The durability of internally cured concrete (ICC) with silicon–aluminum based fine lightweight aggregate (FLWA) exposed to combined sulfate and wetting–drying attack were conducted through evaluating concrete mass, relative dynamic elastic moduli (RDEM), flexural strength, microstructure and erosion products, with the consideration of various FLWA contents, w / b ratios, volcanic minerals and wetting–drying protocols. Results showed that ICC containing 30% FLWA presented better sulfate resistance with less reduction in mass, RDEM and flexural strength since the internal curing and pozzolanic effect of the silicon–aluminum based FLWA contributed to a denser microstructure. Unfortunately, concrete durability decreased when the FLWA content increased to 60%. A higher w / b ratio of 0.55 weakened the sulfate resistance of ICC given a decrease of up to 0.37%, 4.07% and 24.49% in mass, RDEM and flexural strength, respectively, after 210-day attack. More erosion products as well as a higher strength loss were observed as fly ash content increased to 20%. Adding 10% blast furnace slag improved ICC’s durability with an enhancement of 2.55% in flexural strength under 210 days of attack. An 80 °C-drying temperature speeded up ICC’s deterioration with a strength loss of 83.41% at 168 days, and it also changed the damage mechanism by decomposing erosion products. An accelerated degradation process can be expected in the long-term given a drying temperature of 40 °C, which can be adopted as an erosion accelerator, despite it benefited the concrete durability at the early attack age.