Add more fine gravity values are to be used in proportioning concrete aggregate and use 10 drops of the tamper again. Then add mixtures in which the aggregates will be in their naturally material two more times using 3 and 2 drops of the tamper, moist condition, the requirement in 8.
Level off the material even with the top of the optional, and, if the surfaces of the particles in the sample have mold, remove loose material from the base; and lift the mold been kept continuously wet until tested, the requirement in 8. Employ mechanical aids such as tum- metal surface. After 1 to 3 s, remove the fine aggregate.
If bling or stirring to assist in achieving the saturated surface-dry noticeable moisture shows on the test surface for more than 1 condition, if desired. Continue this operation until the test to 2 s then surface moisture is considered to be present on the specimen approaches a free-flowing condition. Follow the fine aggregate. Make the first trial Highway Research Record No. Continue drying with constant stirring and single size material that slumps when wet, hard-finish paper test at frequent intervals until the test indicates that the towels can be used to surface dry the material until the point is specimen has reached a surface-dry condition.
If the first trial just reached where the paper towel does not appear to be of the surface moisture test indicates that moisture is not picking up moisture from the surfaces of the fine aggregate present on the surface, it has been dried past the saturated particles.
In this case, thoroughly mix a few 9. Procedure millilitres of water with the fine aggregate and permit the specimen to stand in a covered container for 30 min. Then 9. Make all determinations of mass for the onset of the surface-dry condition.
Agitate the cupped fingers of the hand holding the mold. Lightly tamp the pycnometer as described in 9. Start each drop approximately 5 mm above the top surface of 9. Permit the tamper to fall freely under eliminate all air bubbles. Adjust the starting height NOTE 3—About 15 to 20 min are normally required to eliminate the air to the new surface elevation after each drop and distribute the bubbles by manual methods.
Dipping the tip of a paper towel into the drops over the surface. Remove loose sand from the base and pycnometer has been found to be useful in dispersing the foam that lift the mold vertically. If surface moisture is still present, the sometimes builds up when eliminating the air bubbles. Optionally, a small fine aggregate will retain the molded shape. Slight slumping of amount of isopropyl alcohol may be used to disperse the foam.
A level. A me- R2. Calculations 9. Record this initial reading gravity , g with flask and contents within the temperature range of Add 55 6 5 g of fine aggregate in the saturated After all fine aggregate has been introduced, place the oven-dry aggregate as follows: stopper in the flask and roll the flask in an inclined position, or Take a final reading with the flask and Relative density specific gravity SSD 0.
Apparent relative density apparent specific 5 6 gravity 0. The precision estimates were obtained from the analysis of combined AASHTO Materials Reference Laboratory proficiency sample data from basis of oven-dry aggregates as follows: laboratories using 15 to h saturation times and other laboratories using 24 6 Testing was performed on normal weight aggregates, and started with aggregates in the oven-dry condition.
Precision and Bias These notes and footnotes excluding those in tables and figures shall not be considered as requirements of this test method. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
Relative density specific gravity is the characteristic generally used for calculation of the volume occupied by the aggregate in various mixtures containing aggregate including portland cement concrete, bituminous concrete, and other mixtures that are proportioned or analyzed on an absolute volume basis.
Relative density specific gravity SSD is used in the determination of surface moisture on fine aggregate by displacement of water in Test Method C Relative density specific gravity SSD is used if the aggregate is wet, that is, if its absorption has been satisfied. Conversely, the density or relative density specific gravity OD is used for computations when the aggregate is dry or assumed to be dry.
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These cookies do not store any personal information. Last previous edition C — The laboratory standard for absorption is that obtained after submerging dry aggregate for a prescribed period of time.
Aggregates mined from below the water table commonly have a moisture content greater than the absorption determined by this test method, if used without opportunity to dry prior to use. Conversely, some aggregates which have not been continuously maintained in a moist condition until used are likely to contain an amount of absorbed moisture less than the h soaked condition.
For an aggregate that has been in contact with water and that has free moisture on the particle surfaces, the percentage of free moisture is determined by deducting the absorption from the total moisture content determined by Test Method C by drying. The values obtained for absorption by other test methods will be different than the values obtained by the prescribed h soak, as will the density SSD or relative density specific gravity SSD.
In fact, the absorption potential for many such aggregates is not satisfied after several days immersion in water. Therefore, this test method is not intended for use with lightweight aggregate.
Summary of Test Method 4. It is then removed from the water, the water is dried from the surface of the particles, and the mass determined.
Subsequently, the sample or a portion of it is placed in a graduated container and the volume of the sample is determined by the gravimetric or volumetric method. Finally, the sample is oven-dried and the mass determined again. Using the mass values thus obtained and formulas in this test method, it is possible to calculate density, relative density specific gravity , and absorption.
Apparatus 6. Within any g range of test load, a difference between readings shall be accurate within 0. A volumetric flask of cm3 capacity or a fruit jar fitted with a pycnometer top is satisfactory for a g test sample of most fine aggregates. The metal tamper shall have a mass of 6 15 g and a flat circular tamping face 25 6 3 mm in diameter.
Significance and Use 5. Relative density specific gravity SSD is used in the determination of surface moisture on fine aggregate by displacement of water in Test Method C Relative density specific gravity SSD is used if the aggregate is wet, that is, if its absorption has been satisfied. Conversely, the density or relative density specific gravity OD is used for computations when the aggregate is dry or assumed to be dry.
This value is not widely 2 C 8. Test by dropping a handful of the fine aggregate from the cone test onto a surface from a height of to mm, and observe for fines becoming airborne; presence of airborne fines indicates this problem. For these materials, consider the saturated surface-dry condition as the point that one side of the fine aggregate slumps slightly upon removing the mold.
Sampling 7. Thoroughly mix the sample and reduce it to obtain a test specimen of approximately 1 kg using the applicable procedures described in Practice C Preparation of Test Specimen 8.
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