Abstract
This study explores the mechanical performance and chloride resistance of concrete incorporating artificial aggregate (AA) synthesized from low-calcium fly ash using an environmentally friendly process. The AA was produced by combining fly ash with a small amount of Portland cement and a low concentration of sodium hydroxide, followed by mild heat curing. The hardened material was crushed and used as coarse aggregate in artificial aggregate concrete (AAC). Concrete mixes were prepared with two water-to-cement (W/C) ratios (0.49 and 0.67), and their performance was compared with that of natural aggregate concrete (NAC). Compressive strength tests at 28 days showed that AAC had significantly lower strength than NAC, attributed to the higher porosity and lower strength of the AA. However, AAC with a W/C of 0.49 still met the minimum structural requirements, suggesting potential for practical application. To assess durability, non-steady-state chloride migration tests were conducted at curing ages of 60 and 120 days. The results demonstrated that AAC exhibited better resistance to chloride ion ingress than NAC, particularly at later ages. This improvement is likely due to pozzolanic reactions between unreacted fly ash in the AA and the surrounding cement paste, leading to progressive densification of the interfacial transition zone (ITZ). These findings highlight the potential of fly ash-based AAC for use in chloride-laden environments and suggest promising durability performance despite its lower mechanical strength.
Keywords
fly ash, artificial aggregate, compressive strength, non-steady-state chloride migration.
Date of Version
2025
DOI
10.5703/1288284318160
Recommended Citation
Mita, Ayesha Ferdous; Luan, Yao; Wang, Tiao; and Ishida, Tetsuya, "Strength and Non-Steady-State Chloride Migration of Concrete Incorporating Fly Ash-Based Artificial Aggregate" (2025). International Conference on Durability of Concrete Structures. 1.
https://docs.lib.purdue.edu/icdcs/2025/icc/1
Strength and Non-Steady-State Chloride Migration of Concrete Incorporating Fly Ash-Based Artificial Aggregate
This study explores the mechanical performance and chloride resistance of concrete incorporating artificial aggregate (AA) synthesized from low-calcium fly ash using an environmentally friendly process. The AA was produced by combining fly ash with a small amount of Portland cement and a low concentration of sodium hydroxide, followed by mild heat curing. The hardened material was crushed and used as coarse aggregate in artificial aggregate concrete (AAC). Concrete mixes were prepared with two water-to-cement (W/C) ratios (0.49 and 0.67), and their performance was compared with that of natural aggregate concrete (NAC). Compressive strength tests at 28 days showed that AAC had significantly lower strength than NAC, attributed to the higher porosity and lower strength of the AA. However, AAC with a W/C of 0.49 still met the minimum structural requirements, suggesting potential for practical application. To assess durability, non-steady-state chloride migration tests were conducted at curing ages of 60 and 120 days. The results demonstrated that AAC exhibited better resistance to chloride ion ingress than NAC, particularly at later ages. This improvement is likely due to pozzolanic reactions between unreacted fly ash in the AA and the surrounding cement paste, leading to progressive densification of the interfacial transition zone (ITZ). These findings highlight the potential of fly ash-based AAC for use in chloride-laden environments and suggest promising durability performance despite its lower mechanical strength.
