WVDOTDOH Materials Procedure: Friable particles in aggregates

What is AASHTO equivalent of this MP?

AASHTO T112

Purpose of MP?

provide standard method for obtaining approximate percent by weight of clay lumps and friable particles in aggregates. Although this test method is performed on a dry, prewashed sample, it is not intended to alter the intent of ASTM C 142.

Scope of MP

applicable to all coarse and fine aggregates when test for friable particles is required.

equipment needed

• balance (conform to requirements of M231)

• Oven (capable maintaining 230F ± 9 (110C ± 5))

• pans (large flat)

• sieves (conform to AASHTO M92; 4.75mm (No.4), 2.36 mm (No. 8), 1.18 mm (No.16), 850 micrometers (No.20).

friable particle

any piece of aggregate that can be broken into smaller particles with thumb and forefinger, excluding use of fingernails

test/ sample prep

• aggregate sample gets washed, oven dried, and sieved over proper sieve

• COARSE agg- over 4.75 mm (No.4) sieve to yield no less than 5000 g on No.4 sieve

• record mass to nearest whole gram

• FINE agg- sieve over a 1.18 mm (No. 16) so as to yield test portion of 200 g retained on No. 16

• record mass to nearest whole gram on WVDOH forms 702-Q and 703-Q

test procedure for friable MP

• spread sieved in thin layer on large pan

• examine for friable particles by squeezing and rolling pieces between thumb and forefinger (DONT use fingernails) and attempting to break them into smaller particles.

• after all have been broken, remove smaller particles from remainder of sample by sieves

• retained: 4.75 mm (No. 4) & 1.18 mm (No.16)

• permitted to pass: 2.36 mm (No.8) & 850 micrometers (No. 20)

calculations for Friables MP

Fp = Mf/M x 100

• Fp: percentage friable particles

• Mf: Mass of friable particles removed after second sieving

• M: Mass of test sample retained on first sieving

  • report results to nearest 0.01%