Comparative Durability of Conventional and Self-Compacting Concrete under Sulfuric and Hydrochloric Acid Exposure

https://doi.org/10.46610/JOCBME.2026.v012i03.003

Abstract

Concrete is used on a larger scale than any other construction material and forms a major part of modern infrastructure. Its combination of strength, adaptability, and relatively low cost supports applications ranging from residential buildings to major bridges and industrial facilities. In chemically aggressive settings, however, including industrial zones, sewage treatment plants, marine environments, and regions affected by acid rain, concrete can experience serious durability problems. This dissertation compares the durability of Conventional Concrete (CC) and Self-Compacting Concrete (SCC) under acidic exposure. Sulfuric acid (H₂SO₄) and hydrochloric acid (HCl) solutions were prepared at concentrations of 3% and 5% by volume. Concrete specimens were then immersed for 28, 56, and 90 days to represent progressively longer periods of acidic exposure. Two SCC mixes were considered: SCC-1 incorporating fly ash and silica fume, and SCC-2 incorporating a higher proportion of the same SCMs. Both were designed in accordance with EFNARC guidelines, whereas the M30 CC mix followed IS 10262:2019. The fresh behaviour of the SCC mixes was checked using slump flow, V-funnel, L-box, J-ring, and segregation resistance tests, with the results assessed against EFNARC requirements. Hardened performance was evaluated in terms of compressive strength, flexural strength, split tensile strength, weight loss, water absorption, and porosity before and after acid exposure. Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) were used for microstructural examination. The test results showed a consistent durability advantage for both SCC mixes over CC during acid exposure. After 90 days, SCC-2 recorded the lowest weight loss in 3% H₂SO₄, at 7.8%, whereas CC lost 18.4%, and SCC-2 also retained substantially greater compressive strength. This behaviour is associated with the denser SCC matrix, its lower water-cement ratio, pore refinement produced by supplementary cementitious materials, and a stronger aggregate-paste interfacial transition zone (ITZ). On the basis of these observations, SCC provides a more durable and sustainable option for concrete structures exposed to acidic conditions.