Chapter 5 practical significance of aggregate specific gravity test results. This procedure covers the determination of specific gravity and absorption of coarse aggregate in accordance with aashto t 8510. Standard test method for relative density specific gravity. Effect of specific gravity on aggregate varies the weight. The absolute volume of a 90lb sample of the aggregate is. Test equipment for determining specific gravity of aggregate. Bulk density and voias of coarse aggregate duration.
Ct 206 october 1, 2011 pdf method of test for specific gravity and absorption of coarse aggregate. The mix design shows fine aggregate absorption to be 2% and coarse aggregate absorption to be 1%. Relative density specific gravity is also used in the computation of voids in aggregate in test method c29c29m. Summing up, the specific gravity of coarse aggregates is indicative of its basic and fundamental quality. Specific gravity is the ratio of the weight of a given volume of aggregate to the weight of an equal volume of water. Specific gravity and fine aggregate kit h3373a kit designed to provide you with the major equipment to do specific gravity and absorption of fine aggregate testing. Specific gravity is defined as the ratio of weight of aggregate to the weight of equal volume of water.
Specific gravity of fine aggregate sand is the ratio of the weight of given volume of aggregates to the weight of equal volume of water. Aashto t84 c128 specific gravity fine aggregate duration. This test method covers the determination of specific gravity and absorption of coarse aggregate. Aggregate unit weight knm3 bulk density example knm3 normalweight 2. Some lightweight shales not used in hma production can have specific gravities near 1. The current method of specific gravity and absorption of coarse aggregate testing is based on the aashto t 85 and astm c127 standards. Aggregates having low specific gravity are generally weaker than those with high specific gravity. Determination of specific gravity of fine aggregates the constructor. So the determination of specific gravity of fine aggregate is very essential. Ct 206 june 1, 2008 pdf ct 206 september 1, 1998 pdf 207.
Aggregates are classified as lightweight, heavyweight and normalweight aggregate depending on weight and specific gravity. This method applies to coarse aggregate, fine aggregate and combined aggregate this was the only method suitable for measuring combined aggregates. Objective specific gravity is defined as the ratio of weight of aggregate to the weight of equal volume of water. Fine aggregate or sand has only one range of particle sizes for general construction and highway work. Bulk specific gravity an overview sciencedirect topics. C330 specification for lightweight aggregates for structural concrete.
Specific gravity and absorption of fine aggregate nebraska. This method of sample reduction is applicable to sands only. Aggregates having low specific gravity are generally weaker than those with high specific. It is similar in nature to the coarse aggregate specific gravity test. The bulk density reflects the volume taken up by the cement plus any air trapped between the p. Gsb and absorption are based on aggregate after soaking in. Coarse aggregate specific gravity pavement interactive. Saturated surfacedry ssd, water fills the aggregate pores. Figure 7 film coefficient curve for the fine sand aggregate. Astmspecific gravity and absorption of aggregate by. A weight of empty basket in water a weight of aggregate and basket in water c. To derive an appropriate equation, lets assume a blend of two aggregates a and b.
A weight of empty basket in water a weight of aggregate and basket in water c weight of ovendried aggregate in air. Some deleterious particles are lighter than the good aggregates. Determining the specific gravities of coarse aggregates. Fine aggregate specific gravity pavement interactive. C127 test method for relative density specific gravity and absorption of coarse aggregate. Mar 09, 2017 the coarse aggregate specific gravity test measures coarse aggregate weight under three different sample conditions. The specific gravity of sands is considered to be around 2. Aashto t 84 specific gravity and absorption of fine aggregate 3. As preconized by siddique 2010b, the bulk specific gravity values of the mswi ash ranges from 1. Aashto t 85 specific gravity and absorption of coarse aggregate ii. This procedure covers the determination of specific gravity and absorption of coarse aggregate in accordance with aashto t 8514. The batch plant operator measures the aggregate moisture and finds that the fine aggregate moisture is at 5%.
Most lightweight concretes use a lightweight coarse aggregate 34 in. This approach involves the soaking of the coarse aggregate samples for 15h aashto t 85 and 24 4 h astm c127, and drying the aggregate to its saturatedsurface dry ssd state with the aid of a dry absorbent cloth. Study on tests fine and coarse aggregate engineering. Improved test methods for specific gravity and absorption of coarse and fine aggregate. The fine aggregate specific gravity test figure 1 is used to calculate the specific gravity of a fine aggregate sample by determining the ratio of the weight of a given volume of aggregate to the weight of an equal volume of water. Specific gravity of fine aggregate can be defined as the ratio of the weight of given volume of coarse aggregate to the weight of given volume of distilled water. Improved test methods for specific gravity and absorption of. Aggregate for lightweight concrete masonry units are normally sized minus 38 in. Mar 24, 2018 specific gravities can vary widely depending upon aggregate type. A low specific gravity may indicate high porosity which often results in poor durability and the low strength of. Specific gravities can vary widely depending upon aggregate type.
The grading and grading limits are usually expressed as the percentage of material passing each sieve. North dakota department of transportation, materials and research. A contract change order may be needed to implement this change for an ongoing contract. It is similar in nature to the fine aggregate specific gravity test. National academies of sciences, engineering, and medicine.
This test method is intended for use in determining the bulk and apparent specific gravity, and absorption of coarse aggregates retained on the. The specific gravity of all other materials are compared to water as a fraction heavier or fraction lighter density, no matter how small or large the fraction is. California test methods version selection caltrans. Determination of specific gravity of fine aggregates. If the fineness modulus is constant, the volume of coarse aggregate increase with size of the aggregate, or with the decrease in surface area of the coarse aggregate the main cause in variation in weight of cube found to be specific gravity of coarse aggregate. Improved test methods for specific gravity and absorption of coarse and fine aggregate develops test methods for determining the specific gravity and absorption of coarse and fine aggregates. A balance of capacity not less than 3kg,readable and accurate to 0. Fine aggregate is used in many fields in sites for many purposes. No%% if the spparcnt spcci6c gravity oniy ia rcquimd the opaztiom described in 2. Read improved test methods for specific gravity and. The bulk density is the mass of the material related to a specific volume and for cement is normally expressed as kilograms per cubic metre. The specific gravity may be expressed as bulk oven dry o. Specific gravity of fine aggregatetest on aggregates. Improved test methods for specific gravity and absorption.
Specific gravity of fine aggregate sand is the ratio of the weight of given volume of. Perform a volumetric sieve analysis when aggregates with differences in bulk specific gravity greater than 0. C566 test method for total evaporable moisture content of. In terms of fine aggregate specific gravity and absorption determination, the. This standard is issued under the fixed designation c 127. Standard test method for relative density specific. Specific gravity relative density of a blended aggregate the specific gravity of a blended aggregate is not simply the weighted average of the specific gravities of the individual components. Ct 207 march 1, 2012 pdf method of test for specific gravity and absorption of fine aggregate. The coarse aggregate, just delivered, has a moisture content of 0. The coarse aggregate specific gravity test measures coarse aggregate weight under three different sample conditions. Bulk ssd specific gravity is used if the aggregate is wet. Specific gravity of coarse aggregate linkedin slideshare. Specific gravity and water absorption tests on aggregates.
Coarse aggregate may be available in several different size groups, such as 19 to 4. Specific gravity may be expressed as bulk specific gravity gsb, bulk specific gravity, saturated surface dry gsb ssd, or apparent specific gravity gsa. Most frequently, the density of coarse aggregate is described using the specific gravity, otherwise known as the relative density, of the coarse aggregate. Based on the findings of experiment 2, it was recommended that aashto t 85 be used for measuring specific gravity and absorption of coarse aggregate and the modified aashto t 84 and ssdetect methods be used for measuring specific gravity and absorption of fine aggregate. The ratio of the weight in air of a unit volume of aggregate at a stated temperature to the weight in air of an equal volume. The specific gravity and porosity of aggregates greatly influence the strength and the water absorption capacity in concrete. Specific gravity and absorption of coarse aggregate. The specific gravity may be expressed as bulk specific gravity, bulk specific gravity ssd or apparent specific gravity.
The determinations that may be made from this procedure are identical to those made in aashto t 85 specific gravity and absorption of coarse aggregate. The specific gravity of an object is the ratio between the density of an object to a reference liquid. The coarse aggregate specific gravity test figure 1 is used to calculate the specific gravity of a coarse aggregate sample by determining the ratio of the weight of a given volume of aggregate to the weight of an equal volume of water. Bulk specific gravity also known as bulk dry specific gravity.
Effect of specific gravity on aggregate varies the weight of. For example, ammonium nitrate has a specific gravity sg of 0. Sand parti cles composed of quartz have a specific gravity rangin g from 2. This test method determines the specific gravity of fine aggregates that have been soaked for a period of 1519 hrs. Aggregates having low specific gravity are generally. Aggregates having low specific gravity are generally weaker than those with higher specific gravity values. The relative density specific gravity, a dimensionless quantity, is expressed as ovendry od, saturatedsurfacedry ssd, or as apparent relative density apparent specific gravity. Specific gravity and absorption capacity of the coarse aggregate. It is the measure of strength or quality of the specific material. Relative density specific gravity is also used in the computation of voids in aggregate in test method c29c29m and in test method c1252. Determination of dry density of soil by sand replacement method. When corresponding fine aggregate specific gravity and absorption are determined on minus no. Usually, our reference liquid is water, which has a density of 1 gml or 1 gcm3.
Determining specific gravity of aggregates im 307 iowa dot. For a particular aggregate type or source, fine aggregate specific gravities can be slightly higher than coarse aggregate specific gravities because as the aggregate particles get smaller, the fraction of pores exposed to the aggregate surface and thus excluded from the specific gravity calculation because they are waterpermeable increases. Bulk specific gravity gsb also known as bulk dry specific gravity the ratio of the weight in air of a unit volume of aggregate at a stated temperature to the weight in air of an equal volume of gasfree distilled water at a stated temperature figure 2. The increase in mass due to water in the pores of the material. Rc1535 development of new test procedures for measuring fine.
Astm c142, which was previously specified for this test, has been superseded and should not be used for routine quality assurance testing. Trbs national cooperative highway research program nchrp report 805. Sfn 2199 72019 pit location laboratory number owner project number sampled from pcn type of material submitted by date received. Absorption and specific gravity specific gravity tctc. C332 specification for lightweight aggregates for insulating concrete. The specific gravity of an aggregate is considered to be a measure of strength or quality of the material.
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