Fineness Modulus for Aggregate
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Questions and Answers

What is the basis for calculating all the percentages in sieve analysis when using Test Method C 117?

  • The total dry sample mass prior to washing (correct)
  • The mass of the material retained on the sieve
  • The initial moisture content of the sample
  • The average mass of the sample after drying

    • How is the fineness modulus calculated in sieve analysis?

  • By adding the total percentages of material coarser than specific sieves and dividing by 100 (correct)
  • By averaging the percentages retained on all sieves
  • By counting the number of sieves used in the test
  • By summing the percentages of material finer than the specified sieves

    • In the sieve analysis, how is the percentage passing determined?

  • From the cumulative percentage of material retained
  • By subtracting total percentages retained from 100% (correct)
  • From individual sieve retention percentages
  • By dividing the mass of the sample by the total dry mass

    • Which of the following materials is included in the sieve analysis calculation when using Test Method C 117?

    <p>Material finer than 75-µm</p> Signup and view all the answers

    Which equipment is not necessary for determining the percentage of evaporable moisture content in aggregates?

    <p>Sieve shaker</p> Signup and view all the answers

    What is the minimum size of the test sample for fine aggregates?

    <p>300 g</p> Signup and view all the answers

    What type of moisture is excluded from the evaporable moisture content calculation?

    <p>Chemically combined water in minerals</p> Signup and view all the answers

    When calculating individual percentages retained in sieve analysis, what is the most appropriate action?

    <p>Divide the mass retained by the total dry sample mass</p> Signup and view all the answers

    Which equipment is NOT mentioned as necessary for the sieve analysis of aggregates?

    <p>Vibrating table</p> Signup and view all the answers

    What is the primary purpose of conducting a sieve analysis on aggregates?

    <p>To determine particle size distribution</p> Signup and view all the answers

    What is a key factor when performing sieve analysis on a sample that had previous moisture content?

    <p>Dry the sample completely before analysis</p> Signup and view all the answers

    What temperature is specified for drying the sample materials of aggregates in an oven?

    <p>110±5°C</p> Signup and view all the answers

    What must not exceed 1% by mass during the sieve analysis process?

    <p>The material passing through any individual sieve in 1 minute</p> Signup and view all the answers

    Which of the following is NOT a type of aggregate mentioned?

    <p>Graded Aggregates</p> Signup and view all the answers

    What should be checked after measuring the retained material on each sieve?

    <p>The total mass must not deviate by more than 0.3% of the original mass</p> Signup and view all the answers

    What is the role of the mechanical sieve shaker in the analysis?

    <p>To separate materials based on particle size</p> Signup and view all the answers

    What is the formula used to calculate the bulk density of aggregates?

    <p>$M = \frac{G - T}{V}$</p> Signup and view all the answers

    What does the factor 'F' represent in the bulk density calculation?

    <p>Factor for the measure</p> Signup and view all the answers

    What is the primary purpose of the ASTM C127 test method?

    <p>Measure the average density of coarse aggregate particles</p> Signup and view all the answers

    Which condition describes the method for measuring SSD density?

    <p>Aggregate is soaked in water for a prescribed duration</p> Signup and view all the answers

    Which value is NOT included when determining the bulk density of aggregates?

    <p>Volume of voids between particles</p> Signup and view all the answers

    Which parameter signifies the dry basis specific gravity in the bulk density formula?

    <p>S</p> Signup and view all the answers

    What is the relationship between density and the state of the aggregate according to the test methods referenced?

    <p>Density can be expressed as oven-dry, saturated-surface-dry, or apparent density</p> Signup and view all the answers

    What is the significance of the term 'apparent density' in aggregate testing?

    <p>It includes the volume of voids between particles</p> Signup and view all the answers

    What does the variable S represent in the density formula?

    <p>Mass of saturated surface-dry specimen for gravimetric procedure</p> Signup and view all the answers

    In the volumetric procedure, which variable corresponds to the final reading of water in the Le Chatelier flask?

    <p>R2</p> Signup and view all the answers

    Which of the following is part of the calculation for apparent density in the gravimetric procedure?

    <p>B + A - C</p> Signup and view all the answers

    What is the primary difference between the gravimetric and volumetric procedures?

    <p>Different formulas for calculating density</p> Signup and view all the answers

    What does the variable C represent in the formulas for density?

    <p>Mass of pycnometer filled with specimen and water</p> Signup and view all the answers

    When calculating density using the volumetric procedure, which factor is multiplied by the density of water?

    <p>S1</p> Signup and view all the answers

    What is the purpose of drying the test sample in the oven?

    <p>To achieve a constant mass for accurate density calculations</p> Signup and view all the answers

    In the gravimetric density formula, what is the constant coefficient used to convert measurements?

    <p>0.9975</p> Signup and view all the answers

    Which of the following correctly describes the relationship in the volumetric density equation?

    <p>Density is calculated using the initial and final readings of the water level</p> Signup and view all the answers

    What is the required soaking time for the test sample in water?

    <p>24 ± 4 hours</p> Signup and view all the answers

    What is one way to ensure all visible films of water are removed from the test sample?

    <p>Roll the sample in a absorbent cloth</p> Signup and view all the answers

    When can the initial drying requirement be considered optional?

    <p>When the aggregates are kept continuously wet before testing</p> Signup and view all the answers

    What condition must be met when determining the mass of the test sample in the saturated surface-dry condition?

    <p>The sample must contain no entrapped air</p> Signup and view all the answers

    What is the maximum temperature allowed for oven drying the test sample?

    <p>110 ± 5 °C</p> Signup and view all the answers

    What must be done immediately after determining the mass in air?

    <p>Submerge the sample for mass determination in water</p> Signup and view all the answers

    What level of precision is required when recording masses?

    <p>Nearest 0.5 g or 0.05 % of the sample mass</p> Signup and view all the answers

    Study Notes

    Fineness Modulus

    • The fineness modulus of an aggregate sample is calculated by adding the total percentages of material coarser than each sieve size and dividing the sum by 100.
    • The sieve sizes used for fineness modulus calculation are 150 µm (No. 100), 300 µm (No. 50), 600 µm (No. 30), 1.18 mm (No. 16), 2.36 mm (No. 8), 4.75 mm (No. 4), 9.5 mm (3/8 in.), 19.0 mm (3/4 in.), 37.5 mm (1 1/2 in.), and larger, increasing in the ratio of 2 to 1.
    • If the same test sample was first tested by Test Method C 117, include the mass of material finer than the 75 µm (No. 200) size by washing in the sieve analysis calculation.
    • Use the total dry sample mass prior to washing in Test Method C 117 as the basis for calculating all percentages.

    Sieve Weights

    • The weight of retained material on each sieve should be measured.
    • The total mass of the retained material should be within 0.3% of the original mass of the dry sample. If not, the test is invalid.
    • The individual percentages of material retained and cumulative percentages passing each sieve should be calculated to the nearest 0.1% based on the total mass of the initial dry sample.

    Bulk Density

    • Bulk density is calculated as the mass of the aggregates divided by the volume of the measure, adjusting for the factor of the measure.
    • The mass of the aggregates plus the measure and the mass of the measure are used in the calculation.

    Voids

    • The percentage of voids in an aggregate sample is calculated using the bulk density, bulk specific gravity, and density of water.
    • The bulk specific gravity is determined in accordance with Test Method C 127 or Test method C 128.

    Relative Density (Specific Gravity) and Absorption of Coarse Aggregate

    • This test method covers the determination of the average density of a quantity of coarse aggregate particles (not including the volume of voids between the particles) and its relative density (specific gravity) and absorption.
    • The relative density is expressed as oven-dry (OD), saturated-surface-dry (SSD), or as apparent relative density (apparent specific gravity) as a dimensionless quantity.
    • The test method is used to determine the density of the solid portion of aggregate particles and provides an average value representing the sample.
    • The method distinguishes between the density of aggregate particles and the bulk density of aggregates as determined by Test Method C 29/C 29M, which includes voids between particle.
    • This method is used to determine the average density of aggregates for the design of different concrete mixtures.

    Procedure for Determining Relative Density (Specific Gravity) and Absorption

    • Dry the test sample in the oven to constant mass at a temperature of 110 ± 5°C and cool in air at room temperature.
    • Immerse the aggregate in water at room temperature for 24 ± 4 hours to essentially fill the pores.
    • Remove the sample from the water and dry the surface with a cloth until all visible films of water are removed.
    • Determine the mass of the test sample in the saturated-surface-dry (SSD) condition.
    • Place the saturated-surface-dry test sample in a container and determine its apparent mass in water.
    • Dry the test sample in the oven to constant mass at a temperature of 110 ± 5°C and cool.
    • Determine the mass of the dry sample.
    • The density and absorption of the aggregate are calculated using the masses and formulas in this test method.

    Density Calculations

    • The density of aggregates is calculated using both gravimetric and volumetric procedures.
    • The gravimetric procedure uses the mass of the oven-dry specimen, the mass of the pycnometer filled with water, and the mass of the pycnometer filled with the specimen and water.
    • The volumetric procedure uses the mass of the saturated-surface-dry specimen and takes readings of the water level in a Le Chatelier flask, before and after immersing the specimen.
    • The density can be calculated in oven-dry, saturated-surface-dry, and apparent density conditions.
    • The calculations for each condition utilize different parameters and formulas.

    Notes:

    • All standards, equipment, and apparatus used in the testing comply with the ASTM standards and specifications.
    • Coarse aggregates are known as gravel, and fine aggregates are known as sand.

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    Description

    This quiz focuses on the calculation of fineness modulus for aggregate samples. It covers the necessary sieve sizes, methods for collecting data, and validation criteria for testing. Test your understanding of these essential concepts in aggregate analysis.

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