University of California Pavement Research Center

This study presents efforts to further inspect the variability of California Test Method CT 371—“Method of Test for Resistance of Compacted Bituminous Mixture to Moisture-Induced Damage”—through the collection of field data. The purposes of this study are (1) to inspect the factors that affect the wet and dry indirect tensile strengths and their ratio (CT 371-TSR); (2) to identify the between- and within-variations of CT 371-TSR; and (3) to evaluate the factors that affect the stabilometer value (S-value). Trellis graphs and tree-based models were used to qualitatively and quantitatively characterize the data structure. Analyses revealed that (1) there is considerable within-variation and noticeable between-variation among CT 371-TSR values, (2) the effect of lime treatment on the CT 371-TSR value is prominent while the effect of liquid anti-strip (LAS) on the CT 371-TSR is far more limited, and (3) the ratio of percent passing at #200 sieve to percent asphalt content (#200/AC) is the most critical factor that affects S-value.