Table 1 Types and conditions of aggregate tests adopted in the present study.

Petrographic analysis^34,35

Optical microscopy in thin sections obtained from representative fragments of stones.

Physical indexes³⁶

Measurements of the dry, saturated, and submerged masses of 10 specimens randomly chosen from the stone fragments sampled in the field.

UCS³⁶

Cylindrical specimens, 75 mm (ballast specification) and 55 mm (conventional) diameters, 2/1 height/ diameter ratio; tests in dry and wet conditions. UCS and R determinations.

PLT^36,37

Cylindrical test specimens (diameters of 75 and 55 mm) subjected to a point load (axial loading), dry and wet conditions.

SHR³⁸

10 single impact readings, separated by at least 1 impact piston diameter. Preliminary measurements on test specimens intended for RCU tests, in dry and wet states.

LAA³⁹

“F” grade: 10,000 ± 75 g particles 50 to 25 mm sieve; abrasive load 5000 ± 25 g; drum speed: 30-33 rpm; 1000 rotations. Final mass is retained in the 1.7 mm sieve. Dry testing.

T³⁶

Three sets of 20 fragments 19 to 16 mm diameter each; final mass of the test sample is retained in a 1.7 mm sieve.

SC⁴⁰

About 10,000 g of particles 12.7 to 9.5 mm sieve; load of 40 tons per sample; rate 4 tons/min. Final sample mass is retained in a 2.4 mm sieve.

Soundness of aggregates by use of Sodium sulfate^36,41

Gradations A (63.5–38 mm), B (38–19 mm), and C (19–9.5 mm) subjected to 5 cycles, consisting of immersion in sodium sulfate solution (18 h) and drying in an oven (4 h).

Soundness by immersion in ethyleneglycol³⁶

Another set of graduations A, B, and C, subjected to 5 cycles, consisting of immersion in ethylene glycol (72 ± 1 h) and drying in an oven (4 h).