Weigh and record graduated cylinder plus compact soil weight (C). These weights are used to calculate specific gravity and the percentage of water absorbed by the sample. Drying should occur in an oven regulated at 230F (110C). Bulk SSD specific gravities can be on the order of 0.050 to 0.100 higher than bulk oven dry specific gravities, while apparent specific gravities can be 0.050 to 0.100 higher still. If more than 2 percent water by volume is absorbed by the sample then this method is not appropriate. The standard coarse aggregate specific gravity and absorption test is: Specific gravity is a measure of a materials density (mass per unit volume) as compared to the density of water at 73.4F (23C). The International Information Center for Geotechnical Engineers, Step-by-Step Guide for Grain Size Analysis, VertekCPT: All you need to know about Soil Liquefaction, Using Terzaghis Equation in Foundation Design, Geotechnical Engineering Lab Manual, by Prof. William A. Kitch (Angelo State University), A list of Videos on Laboratory Testing to support Online Instruction, Splitting Tensile Strength Test (Brazilian), Volumetric flask marked with a thin ring at a specific point of its neck (graduation mark), Weigh the empty and clean volumetric flask (. Therefore, the Specific Gravity GS is calculated as: A correction is utilized to adjust the results at a reference temperature T=20C: where K is the temperature correction factor. Your email address will not be published. How to Calculate and Solve for Air Content of the Soil | Soil Mechanics and Foundation, How to Calculate and Solve for Water Content | Soil Mechanics and Foundation, How to Calculate and Solve for Inter-atomic Spacing | Braggs Law, How to Calculate and Solve for Conversion of Volume Fraction to Mass Fraction | Phase Transformation, How to Calculate and Solve for Net Force between Two Atoms | Crystal Structures, How to Calculate and Solve for Planar Density | Crystal Structures, How to Calculate and Solve for Linear Density | Crystal Structures, https://play.google.com/store/apps/details?id=org.nickzom.nickzomcalculator, https://play.google.com/store/apps/details?id=com.nickzom.nickzomcalculator, https://itunes.apple.com/us/app/nickzom-calculator/id1331162702?mt=8. Dry the material until it maintains a constant mass. Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. W = Total weight of soil Now, enter the values appropriately and accordingly for the parameters as required by the Density of water (w) is 22 andDensity of soil (s) is 11. Soil is composed of solids, liquids, and gases. Use a soil spatula to level the top of the sample in the graduated cylinder and add soil with the spatula until the top of the soil sample is exactly even with the 50 mL line this is the bulk volume of compacted soil (B) (1 mL = 1 cm3 ). Clean and thoroughly dry a 100 mL graduated cylinder. The total pore space consists of the voids between sand, silt, and clay particles and voids between soil aggregates. Requirements: g/cm3 ), including solids and pore spaces. Describe the relationship between 1) bulk density and porosity and 2) particle density and porosity. Find the density of soil when the specific gravity of soil particle is 12 and the density of water is 9. V = Volume of soil Therefore, by definition, water at a temperature of 73.4F (23C) has a specific gravity of 1. Therefore, thespecific gravity of soil particleis0.5. However, in practice the paraffin film application is quite difficult and test results are inconsistent. Relation Between Degree of Saturation, Specific Gravity, Water Content, and Void Ratio The degree of saturation may be defined as the ratio of the volume of water in the soil mass to the volume of voids in the soil mass. Slowly add Soil Sample #1 to pre-weighed graduated cylinder to the 10 mL line. Example 4: Determine void ratio, porosity, and degree of saturation based on known volume, weight, and specific gravity (English units) Given: (metric units) Volume of soil mass: 0.0283 m 3. From $\gamma = \dfrac{(G + Se)\gamma_w}{1 + e}$ and $\gamma = \dfrac{(G + Gw)\gamma_w}{1 + e}$, S = 0 and w = 0, Saturated Unit Weight (S = 1) It is denoted by G. Lets solve an example; Bulk density is a commonly measured soil property by agriculturalists and engineers. The general values for specific gravity for different soils are given in Table -1. W = Weight of Dry Piece in Fluid. Weight of soil after dry in oven: 45.5 kg. When the soil contains particles larger than the 4.75-mm sieve, Test Method C127 shall be used for the soil solids retained on the 4.75-mm sieve and these test methods shall be used for the . What is the range of bulk density values for an organic soil? Organic matter and porous particles may havespecific gravityvalues below 2.0 and Soil which has heavy substances or particles may have values above 3.0. These methods, based on Archimedes Principle, calculate specimen volume by weighing the specimen (1) in a water bath and (2) out of the water bath. Weight-Volume Relationship from the Phase Diagram of Soil. The bulk specific gravity is the ratio of the weight of a given volume of aggregate, including the permeable and impermeable voids in the particles, to the weight of an equal volume of water ( Kandhal et al., 2000; Prowell and Baker, 2004; Sholar et al., 2005 ). Bulk Specific Gravity Formula. at least ten times from a height of about 2-3 inches. Back in the lab, weigh each canister plus moist soil. Examples of suitable units have been shown below. Vv = Volume of voids However, of specific concern is the mass of the SSD sample. The specific gravity of soil can be calculated by using the following formula, G = Mass of soil / Mass of equal volume of water, G = Mass of soil / Mass of equal volume of water, Mass of the same volume of water, Ww = (W1 + Ws) W2. Want to create or adapt books like this? Water Content or Moisture Content, w They are also useful as study notes for exams. Laboratory samples are typically dry at the beginning of the test; however, field samples will typically be damp. The coarse aggregate specific gravity test measures coarse aggregate weight under three different sample conditions: Using these three weights and their relationships, a samples apparent specific gravity, bulk specific gravity and bulk SSD specific gravity as well as absorption can be calculated. Correct and accurate bulk specific gravity determinations are vital to proper mix design. Insert a 1.5 cm metal ring, a 6 cm metal core, and then a second 1.5 cm metal ring into the barrel of the core sampler, then reattach the barrel to the handle. = Weight of water. Weight of soil mass at moist condition: 56.6 kg. You must have JavaScript enabled to use this form. [4] 2 Use the relationship between volume and density to derive your equation. To get the answer and workings of the bulk density using the Nickzom Calculator The Calculator Encyclopedia. To derive the Specific Gravity of a soil, the following equipment is needed: The Specific Gravity is computed as the ratio of the weight in air of a given volume of soil particles at a stated temperature to the weight in air of an equal volume of distilled water at the same temperature. When the desired depth is reached, the device is removed from the soil, and the removable metal cylinder containing the soil sample is removed. This is because asphalt binder that is absorbed by the aggregate is not available to coat the aggregate particle surface and is therefore not available for bonding. Since the specimen is completely wrapped when it is submerged, no water can get into it and a more accurate volume measurement is theoretically possible. TheSpecific gravity of soil generally ranges from 2.60 to 2.90. Density refers to a mass per unit volume. 1993 AASHTO Flexible Pavement Structural Design, 1993 AASHTO Rigid Pavement Structural Design, Climate Change Impacts on Pavements and Resilience, E-Construction in Practice: A Peer Exchange with WSDOT and TxDOT. In this case, use AASHTO T 275, Bulk Specific Gravity of Compacted Bituminous Mixtures Using Paraffin-Coated Specimens or AASHTO TP 69, Bulk Specific Gravity and Density of Compacted Asphalt Mixtures Using Automatic Vacuum Sealing Method. Drying should occur in an oven regulated at 230F (110C). A quick check of the results should show that bulk specific gravity is the lowest specific gravity, bulk SSD specific gravity is in the middle and apparent specific gravity is the highest. Remove the vacuum, clean and dry the flask and add distilled water up to the mark. Calculate the moisture content of the samples: Calculate the dry weight of the soil in each cylinder and record the data. An incorrect specific gravity value will result in incorrect calculated volumes and ultimately result in an incorrect mix design. It is an important parameter in soil mechanics for the calculation of the weight-volume relationship. Samples for determining bulk density must be collected very carefully to insure the sample represents the in situ condition desired and no additional compaction or loosening has occurred. $\rho = \dfrac{m}{V}$. Upon completion of this exercise you should be able to: From Brady and Weil, The Nature and Properties of Soils, 13 th Ed. The procedure that is followed towards that goal is the following: To better understand how the Specific Gravity is calculated, the aforementioned measured quantities are presented in Figure 1. Therefore, after the wax sets there is no possibility of it draining out and, theoretically, a more accurate volume can be calculated. Either type of error will have a cascading effect on volumetric parameters in other tests that require specific gravity as an input and Superpave mix design. Bulk specific gravity is involved in most key mix design calculations including air voids, VMA and, indirectly, VFA. The Specific Gravity of soils is usually between 2.65-2.80 with finer soils having higher values than coarser ones. w = water content or moisture content, Density of water and gravitational constantw = 1000 kg/m3w = 1 g/ccw = 62.4 lb/ft3 The problem set will be provided to you at the beginning of the laboratory session. Submerge sample in 77F (25C) water for 4 minutes and record the submerged mass . The formulas for calculating bulk density and particle density follow: [latex]\text{Bulk density, }_\text{b}=\frac{\text{mass of oven dry soil}}{\text{total soil volume}}[/latex], [latex]\text{Particle density, }_\text{p}=\frac{\text{mass of oven dry soil}}{\text{volume of soil solids}}[/latex]. The formula for bulk density is (mass of dry soil) / (total volume of soil), 1 - (bulk density/particle density) for porosity, and (volume of pores) / (volume of solids) for void ratio.. As mentioned in the background section, if a specimens air voids are high, and thus potentially interconnected (for dense-graded HMA this occurs at about 8 to 10 percent air voids), water quickly drains out of them as the specimen is removed from its water bath, which results in an erroneously low SSD weight, which leads to an erroneously low HMA sample volume measurement and thus an erroneously high bulk specific gravity. Paper towels may absorb water in the aggregate pores. SG = / W. Gs= Specific Gravity of Soil Particle The voids, or pore space, are important for air and water movement and storage. Aggregate specific gravity is used in a number of applications including Superpave mix design, deleterious particle indentification and separation, and material property change identification. The Soil Specific Gravity is defined as the ratio of the weight of a given volume of the material to the weight of an equal volume of distilled water. 6. This can be done with a water-filled container on top of a scale or with a basket suspended in water under a scale (Figure 2). Remove the barrel from the sampler and gently push the core out of the top of the barrel, taking care to keep the core intact. You can also try thedemoversion viahttps://www.nickzom.org/calculator. Troxler Electronic Laboratories, Inc. (Troxler). Porosity is usually expressed as a decimal, but it can also be expressed as a percentage by multiplying the decimal form by 100%. If a soil is compacted, the soil solids are packed into a smaller volume, and the particles get packed closer together. Specific gravity is a unitless measurement of a sample's density relative to water. $\gamma = \dfrac{(G + Se)\gamma_w}{1 + e}$, $\gamma = \dfrac{(G + Gw)\gamma_w}{1 + e}$, $\gamma_{sat} = \dfrac{(G + e)\gamma_w}{1 + e}$, $\gamma ' = \dfrac{(G - 1)\gamma_w}{1 + e}$, $D_r = \dfrac{e_{max} - e}{e_{max} - e_{min}}$, MATHalino - Engineering Mathematics Copyright 2023. G= Specific gravity of soils. Contents [ hide] Description. The ratios given in the equations are then simply the ratio of the weight of a given volume of aggregate to the weight of an equal volume of water, which is specific gravity. One method for determining bulk density is the core method. The relative density (specific gravity) of an aggregate is the ratio of its mass to the mass of an equal volume of water. Determine the weight of dry soil in the sample. Ps = Ms/ (500-Vw) Now that you have the density of soil solids, you can calculate the specific gravity of soil solids (SG). Obtain a sample of coarse aggregate material retained on the No. Liquids and gases are mostly water and air, respectively. Remove the aggregate from the water and dry it until it maintains a constant mass. Between 20o C and 25o C the density of water is essentially 1 g/cm3. The LibreTexts libraries arePowered by NICE CXone Expertand are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. Question. But instead of having g in the formula, use the density of water replacing the unit weight of water. Now add exactly 50 mL of water to the graduated cylinder, record volume (E). It is represented as 'Gm'. Bulk SSD specific gravities can be on the order of 0.050 to 0.100 higher than bulk oven dry specific gravities, while apparent specific gravities can be 0.050 to 0.100 higher still. Your lab instructor will help you as needed. s = Density of Soil = 156. The formula for calculating specific gravity of soil particle: G s = s / w Where: G s = Specific Gravity of Soil Particle w = Density of Water s = Density of Soil Let's solve an example; Find the specific gravity of soil particle when the density of water is 22 and the the density of soil is 11. The figure shown below is an idealized soil drawn into phases of solids, water, and air. The value of specific gravity (soil) varies between 2.65-2.80. Finally, specific gravity differences can be used to indicate a possible material change. Gs = Specific Gravity of Soil Particle = 12 Find the mass of the soil when the bulk density is 10 and the volume of the soil is 4. sb = Bulk Density = 10 Lets solve an example; weight of dry piece soaked in fluid, weight of dry piece soaked & immersed in fluid values. Plasticity index, $PI = LL - PL$, Liquidity index, $LI = \dfrac{MC - PL}{PI}$, Activity of clay, $A_c = \dfrac{PI}{\mu}$, where $\mu$ = soil finer than 0.002 mm in percent, Other Formulas HMA bulk specific gravity is needed to determine weight-volume relationships and to calculate various volume-related quantities such as air voids and voids in mineral aggregate (VMA). Specific gravity is the ratio of the mass of unit volume of soil at a stated temperature to the mass of the same volume of gas-free distilled water at a stated temperature. Nickzom Calculator The Calculator Encyclopedia is capable of calculating the specific gravity of soil particle. specific gravity, also called relative density, ratio of the density of a substance to that of a standard substance. One critical problem with this method is that if a specimens air voids are high, and thus potentially interconnected (for dense-graded HMA this occurs at about 8 to 10 percent air voids), water quickly drains out of them as the specimen is removed from its water bath, which results in an erroneously low HMA sample volume measurement and thus an erroneously high bulk specific gravity. 4) sieve, by means of a water pycnometer. $\gamma_s = G\gamma_w$, $\dfrac{W_s}{V_s} \cdot \dfrac{W_w}{W_w} = G\gamma_w$, $\dfrac{W_w}{V_s} \cdot \dfrac{W_s}{W_w} = G\gamma_w$, $\dfrac{W_w}{V_s} \cdot \dfrac{1}{W_w/W_s} = G\gamma_w$, $\dfrac{\gamma_w V_w}{V_s} \cdot \dfrac{1}{w} = G\gamma_w$, $\dfrac{V_w}{V_s} \cdot \dfrac{1}{w} = G$, $\dfrac{V_w}{V_s} \cdot \dfrac{V_v}{V_v} = Gw$, $\dfrac{V_w}{V_v} \cdot \dfrac{V_v}{V_s} = Gw$. emax = void ratio of the soil at its loosest condition The difference in weights can then be used to calculate the weight of water displaced, which can be converted to a volume using the specific gravity of water. The formula for calculating bulk density: sb= Bulk Density Calculation Examples. Write a mathematical expression for these relationships. Bulk Specific Gravity Calculator. If this water is not weighed, significant error can result.
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