Coarse Absportion

Coarse Absportion - The measurement should be taken to the...

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ASTM C 127 (AASHTO No. T 85) Standard Test Method for Specific Gravity and Absorption of Coarse Aggregate Equipment Balance and sieves Water tank Sampling Minimum weight of test sample is dependant upon nominal maximum size. Aggregates passing the No. 4 sieve are not used in this test. For this test, you need approximately 2500 g of the sample. Procedures 1. Dry sample at a temperature range of 105-115 o C until there is no mass change in the aggregate. 2. Let the aggregate cool until it is comfortable to handle. 3. Wash the aggregate to remove dust and deleterious materials. 4. Submerge the aggregate in water at room temperature for 24 hrs. 5. Remove sample from the water, and roll it in an absorbing cloth. This is to take excess surface moisture off the aggregates. The cloth should be damp, but not soaked. The aggregate should no longer be shiny. 6. Weigh the sample. This is saturated surface dry mass.
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Unformatted text preview: The measurement should be taken to the 0.5 g. 7. The aggregates then must be weighed in water. Let the aggregates soak for about 3 minutes in the bulk station. Take this weight. 8. Dry the test sample for 1 to 3 hours in an oven. Remove, let cool, and weigh again. In this lab, we will let the aggregate dry over night. Calculations • Bulk Specific Gravity ) ( submerged air dry oven sb SSD SSD Mass G-=-• Bulk Specific Gravity (SSD) ) ( submerged air air ssd SSD SSD SSD G-= • Apparent Specific Gravity ) ( submerged dry oven dry oven sa SSD Mass Mass G-=--• Absorption 100 * ] [ % ovendry ovendry air Mass Mass SSD Abs-= Significance and Use • Bulk specific gravity is vital for volumetric calculations. • Apparent specific gravity relates to the density of the solid. It excludes the pore space of the aggregate....
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