Aashto

EMBANKMENT AND BASE IN-PLACE DENSITY

WAQTC

AASHTO T 224

CORRECTION FOR COARSE PARTICLES IN THE SOIL COMPACTION TEST FOP FOR AASHTO T 224 (07) Scope This procedure covers the adjustment of the maximum dry density determined by FOP for AASHTO T 99/ T 180 to compensate for coarse particles retained on the 4.75 mm (No. 4) or 19.0 mm (3/4 in.) sieve. For Methods A and B of FOP for AASHTO T99/ T 180 the adjustment is based on the percent, by mass, of material retained on the 4.75 mm (No. 4) sieve and the bulk specific gravity Gsb of the material retained on the 4.75 mm (No. 4) sieve. A maximum of 40% of the material can be retained on the 4.75 mm (No. 4) sieve for this method to be used. For Methods C and D of FOP for AASHTO T 99/ T 180, the adjustment is based on the percent, bymass, of material retained on the 19.0 mm (3/4 in.) sieve and the bulk specific gravity Gsb of the material retained on the 19.0 mm (3/4 in.) sieve. A maximum of 30% of the material can be retained on the 19.0 mm (3/4 in.) sieve for this method to be used. Whether the split is on the 4.75 mm (No. 4) or the 19.0 mm (3/4 in.) sieve all material retained on that sieve is defined as oversized material.This method applies to soils with percentages up to the maximums listed above for oversize particles. A correction may not be practical for soils with only a small percentage of oversize material. Agency shall specify a minimum percentage below which the method is not needed. If not specified, this method applies when more than 5 percent by weight of oversize particles is present. AdjustmentEquation Along with density the moisture content can be corrected. The moisture content can be determined by the FOP for AASHTO T 255 / T 265, FOP for AASHTO T 217, or the nuclear density gauge moisture content reading from the FOP for AASHTO T 310. If the nuclear gauge moisture reading is used or when the moisture content is determined on the entire sample (both fine and oversized particles) the use ofthe adjustment equation is not needed. Combined moisture contents with material having an appreciable amount of silt or clay should be performed using FOP for AASHTO T 255 / T 265 (Soil). Moisture contents used from FOP for AASHTO T 310 must meet the criteria for that method. When samples are split for moisture content (oversized and fine materials) the following adjustment equations must befollowed. 1. Split the sample into oversized material and fine material. 2. Dry the oversized material following the FOP for AASHTO T 255 / T 265 (Aggregate). If the fine material is sandy in nature dry using the FOP for AASHTO T 255 / T 265 (Aggregate), or FOP for AASHTO T 217. If the fine material has any appreciable amount of clay, dry using the FOP for AASHTO T 255 / T 265 (Soil) or FOP for AASHTOT 217. 3. Calculate the dry mass of the oversize and fine material as follows.

T224_short

E&B/ID 21-1

October 2007

EMBANKMENT AND BASE IN-PLACE DENSITY

WAQTC

AASHTO T 224

MD =

Mm (1 + MC )

Where: MD = mass of dry material (fine or oversize particles). Mm = mass of moist material (fine or oversize particles). MC = moisture content of respective fine or oversized,expressed as a decimal. 4. Calculate the percentage of the fine and oversized particles by dry weight of the total sample as follows: See note 2.

Pf =
And

100 M DF (M DF + M DC )

73.0% =

(100) (15.4 lbs) (15.4lbs + 5.7lbs )

73.0% =

(100) (7.034kg) (7.034kg + 2.602kg )

Pc =

100 M DC (M DF + M DC )

27.0% =

(100) (5.7lbs) (15.4lbs + 5.7lbs )

27.0% =

(100) (2.602kg)(7.034kg + 2.602kg )

Or for Pc Where:

Pc = 100 - Pf

= percent of fine particles, of sieve used, by weight. PC = percent of oversize particles, of sieve used, by weight. MDF = mass of fine particles. MDC = mass of oversize particles. 5. Calculate the corrected moisture content as follows:
[(MC F ) (Pf ) + ( MC c )( Pc )] 100

Pf

MC T =

8.3% =

[(10.6) (73.0) + (2.1)(27.0)] 100...