Performance Evaluation of Crystalline Admixture Blended High-Performance Concrete for Sustainable and Long-Life Infrastructure

Abstract

High-Performance Concrete (HPC) has become an essential construction material for modern infrastructure due to its superior strength, durability, and long-term performance. However, concrete structures exposed to aggressive environments are vulnerable to the ingress of chloride ions, which can initiate reinforcement corrosion and reduce service life. The present study investigates the influence of crystalline admixture on the mechanical and durability properties of M60 grade High-Performance Concrete. Two concrete mixes were prepared: a control mix without crystalline admixture and an experimental mix incorporating crystalline admixture. The performance of both mixes was evaluated through compressive strength tests at 7, 28, and 56 days, along with durability assessments using the Rapid Chloride Penetration Test (RCPT) and Rapid Chloride Migration Test (RCMT). The results showed that the concrete containing crystalline admixture exhibited higher compressive strength at all curing ages, achieving 59.37 MPa, 83.56 MPa, and 89.92 MPa at 7, 28, and 56 days, respectively, compared to the control mix. The RCPT value decreased from 650 Coulombs for the control mix to 562 Coulombs for the crystalline admixture concrete, while the chloride migration coefficient was reduced from 2.16 × 10⁻¹² m²/s to 1.41 × 10⁻¹² m²/s, indicating significantly improved resistance to chloride penetration. The enhanced performance is attributed to pore refinement, matrix densification, and the continued formation of crystalline reaction products, resulting in a denser and less permeable concrete microstructure. The findings demonstrate that crystalline admixture is an effective material for improving both the strength and durability of High-Performance Concrete, making it suitable for reinforced concrete structures exposed to aggressive environmental conditions.