The voids, or pore space, are important for air and water movement and storage. 1.1 These test methods cover the determination of the specific gravity of soil solids that pass the 4.75-mm (No. Particle density is approximated as 2.65 g/cm3 , although this number may vary considerably if the soil sample has a high concentration of organic matter, which would lower particle density, or high-density minerals such as magnetite, garnet, hornblende, etc. Download Solution PDF. Volume of water in soil is also often expressed by equivalent depth of water, D e: D This indicates that all the water has left the sample. Rolling up the aggregate into the towel and then shaking and rolling the aggregate from side to side is usually effective in reducing the sample to a SSD condition (Video 1). If the specific gravity of soil grains is 2,65, the value of critical hydraulic gradient for the soil will be (Assume Yw = 10 kN/m) A sand sample has a bulk density of 20kN/m and a degree of saturation of 70%. Although the Test Description section describes the standard AASHTO T 166 saturated surface dry (SSD) water displacement method, there are a number of other methods available. These weights are used to calculate specific gravity and the percentage of water absorbed by the sample. What is the range of bulk density values for an organic soil? The driving weight is raised and dropped repeatedly to drive the sampler into the soil. Absorption should typically be below 2 percent. Coarse aggregate apparent specific gravity. SG = / W. emin = void ratio of the soil at its densest conditiond = current dry unit weight of soil in-situ Bulk Specific Gravity Formula. Use a vacuum pump to gradually apply vacuum and remove the entrapped air while spinning the flask to remove the air bubbles. The determination of SSD conditions can be difficult. However, direct volume measurements are difficult, therefore weight measurements are usually made and then converted to a volume based on material specific gravities. These two (water and air) are called voids which occupy between soil particles. Some state agencies specify minimum aggregate specific gravities or maximum percent water absorption to help control aggregate quality. The following description is a brief summary of the test. Data Analysis. m = Mass of the Soil. The specific gravity of soil can be calculated by using the following formula,G = Mass of soil / Mass of equal volume of water Where, Mass of Soil = Ws Mass of the same volume of water, Ww = (W1 + Ws) W2 Gs (T1 C) = Ws / Ww, Copyright [2019 - 2023] [Civiconcepts.com] | by [Bhushan Mahajan], 3040 House Plans | 1200 sq ft House Plan, Specific Gravity of Soil Test Procedure, Result & Calculation, General Specific Gravity of Soil Range for Various Soils, Determination of Specific Gravity Test of Soil, Calculation Of Specific Gravity Of Soil Sample, Specific Gravity of Soil at Various Temperature, Specific Gravity of Soil Lab Report Discussion, Water Content of Soil Test Procedure, Result & Report, Ultrasonic Pulse Velocity Test on Concrete, Soundness Test of Cement Procedure and Results, Abrasion Test on Aggregate & Its Procedure, Compressive Strength of Concrete Cube Test Result 7, 14, 28 Days, What To Do If Concrete Cube Fails After 28 days, Cement of Fineness: Definition, Importance, and How to Test It, 8 Different Types Of Mop With Pros & Cons, 5 Different Types of Chains In Civil Engineering, What Is Architecture | 8 Types of Architects | Different Types of Architecture | Top Architecture Types With Pictures, 8 Different Types of Air Conditioners With Pros & Cons, 30 Types Of Shed | Different Types Of Shed In Backyard | Types Of Backyard Shed | Best Shed Styles Designs, 12 Different Types of Gardens | Most Popular Types of Gardening | Top Garden Types With Pictures, Defects In Timber | Top Defects Of Timber | 5 Different Types of Defects In Timber | Foxiness In Timber, Different Types of Chimneys For Kitchens [Pros & Cons], 15 Types of Drywall Anchors | Different Types Of Wall Anchors | Dry Wall Anchors Types | Best Types of Wall Anchors For Wall, Types Of Gutters | 22 Different Types of Gutters | Rain Gutter Downspout | Best Types of Rain Gutter For House, Explore the 15 Different Types of Door Locks for Home Security, 8 Different Types of Kitchen Cabinets for Your Dream Kitchen, 12 Types of Rugs | Different Types of Rugs With Pictures | Best Types of Rug For Living Room | Best Rug For Bedroom, Different Types of Roof Overhang and Their Advantages, 15 Different Types of Fans For Home | Ceiling Fan Type, 10 Different Types of Stoves For Your Kitchen, 22 Different Types of Drill Bits and Their Uses [PDF], Thermometer graduated in O.soC division scale. Porosity is the ratio of the volume of the pores in a soil sample to the total volume of the sample: [latex]\text{Porosity, }=\frac{\text{volume of pores}}{\text{total soil volume}}[/latex]. With the dimensions of the cylinder and the weight of oven-dry soil inside the cylinder, we can calculate the bulk density. Though not critical, it is important that we know it. Pavement Interactive was developed by thePavement Tools Consortium, a partnership between several state DOTs, the FHWA, and the University of Washington, as part of their effort tofurther develop and use computer-based pavement tools. Specific gravity is a unitless measurement of a sample's density relative to water. 5. Selected Topics. This is because in the normal procedure the water may not be able to penetrate the pores to the center of the aggregate particle during the soaking time. 3 days (from sample preparation to final dry weight determination). Android (Free)https://play.google.com/store/apps/details?id=com.nickzom.nickzomcalculator document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Your email address will not be published. s= Density of Soil Find the bulk density when the mass of the soil is 24 and the volume of the soil is 6. m = Mass of the Soil = 24 $W = W_s + W_w$. Some lightweight shales (not used in HMA production) can have absorptions approaching 30 percent, while other aggregate types can have near zero absorption. 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. The basket should be pre-conditioned to the water bath temperature. The determination of the specific gravity method is as follows: The measuring flask with 1000ml capacity is weighed for the determination of its empty weight denoted by W 1. Unit weight is the weight of soil per unit volume. If absorption is incorrectly accounted for, the resulting HMA could be overly dry and have low durability (absorption calculated lower than it actually is) or over-asphalted and susceptible to distortion and rutting (absorption calculated higher than it actually is). The most common method (and the one described in the Test Description section), calculates the specimen volume by subtracting the mass of the specimen in water (Figure 2) from the mass of a SSD specimen. Aggregate absorption is a useful quality because: It is generally desirable to avoid highly absorptive aggregate in HMA. Vv = Volume of voids Particle density is a measure of the mass of soil solids per given volume (g/cm3 ); however, pore space is not included as it is with bulk density. Typically, aggregate used in HMA production will have a bulk specific gravity between about 2.400 and 3.000 with 2.700 being fairly typical of limestone. GS should not be confused with the soil density since it is a dimensionless unit and expresses the ratio of two particular densities. The above values have been provided with both imperial and metric units. Some lightweight shales (not used in HMA production) can have specific gravities near 1.050, while other aggregate can have specific gravities above 3.000. Mass/Bulk/Apparent Specific Gravity It is the ratio of the weight of soil of a given volume to the weight of standard fluid (water) of the same volume. To compute for specific gravity of soil particle, two essential parameters are needed and these parameters areDensity of water (w)andDensity of soil (s). 4 (4.75 mm) sieve. w= Density of Water Place the sampler over the desired sampling location, and then drive it into the soil with the slide hammer at the top of the handle. They are also useful as study notes for exams. But instead of having g in the formula, use the density of water replacing the unit weight of water. Calculate the moisture content of the samples: Calculate the dry weight of the soil in each cylinder and record the data. Question. Apple (Paid)https://itunes.apple.com/us/app/nickzom-calculator/id1331162702?mt=8 Engineering Civil Engineering A sand sample has a bulk density of 20kN/m and a degree of saturation of 70%. Civil Engineering - Texas Tech University 3- Specific Gravity, Gs Definition; specific gravity, Gs, of soil solids is the ratio of the density of the aggregate soil solids to the density of water. Compact the soil by dropping onto a padded surface like a book, notebook, etc. Unit Weight, Therefore, thespecific gravity of soil particleis0.5. The formula for calculating bulk density: s b = m / V Where: s b = Bulk Density m = Mass of the Soil V = Volume of the Soil Let's solve an example; Find the bulk density when the mass of the soil is 24 and the volume of the soil is 6. Units of density are typically expressed in g cm3 or Mg m-3. It is often found that the specific gravity of the materials making up the soil particles are close to the value for quartz, that is Gs 2.65 For all the common soil forming minerals 2.5 < Gs < 2.8 We can use Gs to calculate the density or unit weight of the solid particles s = Gs w s = Gs w Bulk density is the density of a "bulk" of a substance, typically expressed in kg/m3 or similar. This method determines volume similarly to the water displacement method but uses a melted paraffin wax instead of water to fill a specimens internal air voids (Figure 3). Equation (3.21) may be derived by referring to the soil element shown in Figure 3.4, in which the volume of soil solids is equal to 1 and the volume of voids is equal to e. Figure (3.4) Three separate phases of a soil element showing mass-volume relationship Hence, the mass of soil solids, M s, is equal to G s w. The moisture content has been Fill around 2/3 of the flask with distilled water. 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. INSTRUCTIONS: Choose units and enter the following: () The mean density of the object or liquid. Make sure to use cloth and not paper towels. GS is a significant parameter of soil mechanics since it can be associated with the soils mineral composition and weathering. 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. These definitions/questions will provide a concise summary of the major concepts addressed in the lab. Between 20o C and 25o C the density of water is essentially 1 g/cm3. A = mass of oven-dry sample in air (g) To find the formula for density, divide the formula of unit weight by gravitational constant g (acceleration due to gravity). This implies that; m = Mass of the Soil = 24 V = Volume of the Soil = 6 s b = m / V s b = 24 / 6 s b = 4 Laboratory specific gravity and absorption tests are run on two coarse aggregate sizes, which have to be blended. Specific Gravity of Solid Particles, G Simply divide the mass of the sample by the volume of the water displaced. Finally, specific gravity differences can be used to indicate a possible material change. Dry the sample to a saturated suface dry (SSD) condition. s) = Ws/Vs; 12. Therefore, highly absorptive aggregates (often specified as over 5 percent absorption) require more asphalt binder to develop the same film thickness as less absorptive aggregates making the resulting HMA more expensive. Contents [ hide] Description. Lets solve an example; It is not a complete procedure and should not be used to perform the test. $\gamma = \dfrac{(G + Se)\gamma_w}{1 + e}$, $\gamma = \dfrac{(G + Gw)\gamma_w}{1 + e}$, $\gamma_{sat} = \dfrac{(G + e)\gamma_w}{1 + e}$, $\gamma ' = \dfrac{(G - 1)\gamma_w}{1 + e}$, $D_r = \dfrac{e_{max} - e}{e_{max} - e_{min}}$, MATHalino - Engineering Mathematics Copyright 2023. s= Density of Soil. V = Volume of soil It may be necessary to wipe the larger particles separately. Absorption can indicate the amount of asphalt binder the aggregate will absorb. $\rho = \dfrac{m}{V}$. Water Content or Moisture Content, w To compute for bulk density, two essential parameters are needed and these parameters areMass of the soil (m)andVolume of the soil (V). Then find the volume needed in order to have the same bulk density for the other. Several different types of specific gravity are commonly used depending upon how the volume of water permeable voids (or pores) within the aggregate are addressed (Figure 3): The following description is a brief summary of the test. If particle density remains constant, as bulk density increases porosity decreases. This SSD condition allows for internal air voids to be counted as part of the specimen volume and is achieved by soaking the specimen in a water bath for 4 minutes then removing it and quickly blotting it dry with a damp towel. i av = N d at middle of heave soil prism /unit length pile. These values are then used to calculate bulk specific gravity, bulk SSD specific gravity, apparent specific gravity and absorption. Saturated Unit Weight, sat An incorrect bulk specific gravity value will result in incorrectly calculated air voids, VMA, VFA and ultimately result in an incorrect mix design. This method of determining the specific gravity of soil given here is applicable for soils composed of particles smaller than 4.75 mm (No.4 U.S. sieve) in size. A soil sample has a dry density of 8.5 kN/m 3, specific gravity of solids G as 2.7 and voids ratio of 0.6. Soil is a three-phase materialthat consists of solid particles and voids which are filled with water and air. Nickzom Calculator The Calculator Encyclopedia is capable of calculating the bulk density. Apple (Paid)https://itunes.apple.com/us/app/nickzom-calculator/id1331162702?mt=8 Weigh and record graduated cylinder plus compact soil weight (C). Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. The following formulas are taken from unit weights of soil: = ( G + S e) w 1 + e = ( G + G w) w 1 + e d = G w 1 + e s a t = ( G + e) w 1 + e = ( G 1) w 1 + e Where m = mass of soil V = volume of soil W = weight of soil = density of soil d = dry density of soil sat = saturated density of soil ' = buoyant density of soil Android (Paid)https://play.google.com/store/apps/details?id=org.nickzom.nickzomcalculator 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). Remove the lids of all of the canisters, and place each in a 105C oven. i.e, G =ps/pw The specific gravity of solids varies from 2.65 to 2.80 for most natural soils. Density refers to a mass per unit volume. Want to create or adapt books like this? 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. $\gamma = \dfrac{W}{V} = \dfrac{W_s + W_w}{V}$, $\gamma = \dfrac{W_s (1 + W_w/W_s)}{V} = \dfrac{W_s}{V}(1 + w)$, Dry Unit Weight (S = w = 0) The wet soil in the box weighed 450 g. The dry soil weighed 375 g. Now calculate the bulk density. Ans: Because at 4C the unit weight of water is 1. \ (\mathrm {Gm}=\frac {\text { Weight of soil of given soil }} {\text { weight of standard fluid of same volume }}\) Pores that absorb water are also referred to as water permeable voids. Rather, specific gravity is an aggregate quality needed to make required volume calculations. Using the recommended reading and viewing resources and the introduction to this lab, answer the questions listed below. The equipment for this experiment is shown in Fig. 3. Equation for calculate bulk specific gravity is, G b = (W * D) / (W - I) Where, G b > = Bulk Specific Gravity. If the unit weight of soil is 50% saturated, then its bulk unit weight will be _____ If the unit weight of soil is 50% saturated, then its bulk unit weight will be ______ You can also try thedemoversion viahttps://www.nickzom.org/calculator. (2000c). document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Your email address will not be published. Add slightly more than 50 mL of the two soil samples to 50 mL beakers. Porosity is the ratio of volume of voids to the total volume of soil. The jar is now included with 100ml of mineral water. A change in aggregate mineral or physical properties can result in a change in specific gravity. Where SG = specific gravity, = density of the material (kg/m 3 ), W = density of water ( kg/m 3 ). 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. at least ten times from a height of about 2-3 inches. 4. The density of water varies less than 1.5 mg/cm3 over the narrow range of normal temperatures. total volume = volume of soilds + volume of voids 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.