Document Type : Original Research Paper

Authors

• Esmaeel Ramezani ¹
• Mehdi Hosseini ²
• Alireza Dolatshahi ³

¹ Imam Khomeini international university

² Imam khomeini International university

³ Amirkabir University of Technology

Abstract

This study examines the effects of acid rain (pH = 4) and normal rain (pH = 7) on the modes I and II fracture toughness of concrete incorporating 10% zeolite and 10% micro-silica, relative to conventional concrete. Concrete specimens were prepared at ages of 28 and 60 days and subjected to various rainfall cycles, including a dry condition (cycle 0), a single rainfall cycle, and 60 cycles of both normal and acidic rain. All specimens were constructed as CSCBD specimens, and evaluations were conducted on fracture toughness and mechanical properties. Notably, the fracture toughness in modes I and II improved across all modified mixtures under various testing conditions, particularly when exposed to acidic rainfall. Concrete incorporating micro-silica demonstrated increases of 31.9%, 28.9%, and 29.5% in mode I fracture toughness under dry conditions, following 60 cycles of normal rain, and after 60 cycles of acid rain, respectively. Under analogous conditions, the zeolite concrete displayed increases of 14.3%, 9.9%, and 11.0%. Regarding mode II, the micro-silica concrete experienced improvements of 36.2%, 34.1%, and 41.7%, whereas the zeolite concrete recorded respective increases of 30.1%, 20.4%, and 23.8%. Furthermore, the impact of acid rain on the reduction of mode I fracture toughness was found to be more significant than that on mode II, with the concretes modified with micro-silica and zeolite demonstrating superior performance in this aspect as well.

Keywords

• Acid rain
• Concrete
• fracture toughness
• Mechanical properties

Main Subjects

• Rock Mechanics