Reliability-Integrated Optimization of Concrete Mix with Variable Aggregates

Rachna Aggarwal

Abstract: This study presents an integrated approach combining reliability analysis with deterministic optimization for cost-effective concrete mix design while ensuring the required 28-day compressive strength. The mix constituents water, cement, fine aggregate, and coarse aggregate?are modeled as random variables following a normal distribution. The objective function minimizes the overall mix cost subject to boundary, ratio, and reliability constraints on compressive strength. Coarse aggregates are categorized into three zones (A, B, and C), and separate optimization models are developed for each. Numerical results are reported across compressive strength targets ranging from 27 MPa to 51 MPa and reliability levels between 0.90000 and 0.99865. The findings indicate that mixes incorporating Zone C aggregates achieve superior cost efficiency and higher reliability compared to those designed with Zone A or Zone B aggregates.

Keywords: Reliability, optimization, concrete, compressive strength