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T 99 & T 180

AASHTO T 99 AND T 180 MOISTURE-DENSITY RELATIONS OF SOILS

Conduct this procedure according to AASHTO T 99 or AASHTO T 180. Consult the current edition of AASHTO for procedure in its entirety and equipment specification details. The NDDOT modifies this standard to only allow Method A. SCOPE: The moisture-density relationship test is also called the Proctor test. This test methoddetermines the relationship between the moisture content and the density of soils compacted in a mold. Two different standards of moisture-density relationships are presently in use by the NDDOT. They vary mainly in the compaction energy applied to the soil in the mold. The two standards and their features are summarized below. FEATURE Weight of Compaction Rammer Distance of Drop Number of SoilLayers Diameter of Mold Soil Passing Sieve Size Rammer, blows per layer REFERENCED DOCUMENTS AASHTO T 217, Determination of Moisture in Soil by Means of Calcium Carbide Gas Pressure Moisture Tester (Speedy) AASHTO T 265, Laboratory Determination of Moisture Content of Soils ASTM D 2167, Density and Unit Weight of Soil In Place by the Rubber-Balloon Method ASTM D 4643, Microwave Method of DryingSoils AASHTO T 99 5.5 lbs 12" 3 4" No. 4 25 AASHTO T 180 10 lbs 18" 5 4" No. 4 25

APPARATUS Compaction equipment including density mold, base and collar, compacting rammer and guide Balance, readable to 0.01 lbs (5 g) Oven No. 4 (4.75 mm) sieve Mixing tools Moisture sample cans with lids Straightedge, 10” long Knife
T 99 & T180 1 of 5

T 99 & T 180

SAMPLE SIZE A representative soil sampleof approximately 35 lbs (15.9 kg) is required for the multipoint moisture density relationship test. Approximately 7 lbs (3.2 kg) is required for the one-point moisture density relationship test.

MULTI-POINT MOISTURE DENSITY RELATIONSHIP-MECHANICAL & MANUAL PROCEDURE Record information on SFN 10063. Calculate and record to the accuracy indicated. If the soil is damp when received, dry the soiluntil it is easily crumbled under a trowel. The soil can be air dried or oven dried at a temperature up to 140°F (60°C). Break up the soil chunks so that the entire sample passes through the No. 4 sieve. Avoid reducing the natural size of the particles. Discard any individual particles of material retained on the No. 4 sieve or organic material. Divide the sample into five representative samples of7 lbs each. Thoroughly mix the first test sample with water to dampen it approximately four percentage points below optimum moisture. A good indication of a soil being moist enough for the first point is if the soil barely forms a “cast” when squeezed together. The specimen shall be placed in moisture-proof container and covered to prevent moisture loss. Mix the remaining specimens in the samemanner as test sample one, increasing the water content by approximately one or two percentage points (not exceeding 2.5%) over each preceding specimen. This can be accomplished by adding approximately 60 mL of water. Allow soil samples to cure in moisture-proof containers for a minimum of 12 hours. Weigh the empty mold without the base plate or collar and record to the nearest 0.01 lb (5 g). Addsufficient material from test sample one to the mold to produce a compacted layer of approximately 1-3/4” for T 99, or 1" for T 180. Gently level the soil surface in the mold. *Using a manual compaction rammer or a similar device with a 2" face (50 mm), lightly tamp the soil until it is no longer loose or fluffy. Compact the soil with 25 evenly distributed blows of the compaction rammer. After eachlayer, trim any soil along the mold walls that has not been compacted with a knife and distribute on top of the layer. *When completing this process using a mechanical compactor, it is recommended to use a spare or extra replacement rammer. When using a manual compactor, remember to hold the rammer perpendicular to the base of the mold and lift the rammer to its maximum upward position. Repeat...
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