The relationships between Los Angeles abrasion values and brittleness indices of rocks

The Los Angeles abrasion (LAA) value is one of the basic properties of rock aggregates reflecting their resistance to mechanical abrasive factors such as repeated impact loading. Brittleness represents a key mechanical attribute of rocks, exerting a strong influence on their behavior during excavation, drilling, blasting, and aggregate production. This study investigates the relationship between LAA values and five strength-based brittleness indices (B₁-B₅) derived from uniaxial compressive strength (UCS) and Brazilian tensile strength (BTS) values of different rock types. A dataset of 138 rocks (76 sedimentary, 42 igneous, and 20 metamorphic) compiled from 11 literature sources was analyzed using regression methods. Results show that while brittleness indices B₁ and B₂ do not exhibit any significant correlation with LAA, brittleness indices B₃, B₄, and B₅ show moderate inverse-logarithmic relationships across all investigated rock types. After normalization with UCS, brittleness indices B₃, B₄, and B₅ exhibit very strong inverse relationships with LAA values (R² up to 0.96). Normalized LAA significantly improved correlations, particularly for B₃, which provided the most reliable predictor across all rock types according to ANOVA. An empirical model based on B₃ was developed and validated with 16 different rock samples, demonstrating close agreement between measured and predicted LAA values. These findings confirm that strength-based brittleness indices, especially B₃, can serve as robust predictors of aggregate abrasion resistance.