Determination of the flakiness and elongation index for the given aggregate. Elongation index and flakiness index of coarse aggregate. Flakiness and elongation test of aggregate as per is 2386 part 1. Flakiness and elongation of aggregates and concrete properties. The percentage by weight of flaky particles present in a given test sample. Is the combined flakiness and elongation index of aggregate is the numerical sum of separate elongation index and flakiness index. Flakiness index the flakiness index of aggregate is the percentage by weight of particles in it whose least dimension thickness is less than threefifths of their mean dimension. The percentage of flaky and elongated particles that it contains. Apr 07, 20 flakiness and elongation index of aggregate. Shape of coarse aggregates flakiness index of coarse natural aggregate. The flakiness and elongation rocks are not suitable for road construction because this type of rocks will make the road surface not balance and easy to damage. This british standard, a part of the bs 812 series, describes the method for determining the elongation index of coarse aggregate. Flakiness index and elongation index test on coarse aggregates. Flat particles, elongated particles, or flat and elongated particles in coarse aggregates.
Similarly, the particle is considered as flaky if its thickness is less than 0. Aggregate angularity flakiness elongation index gilson co. The standard flat and elongated particles in coarse aggregate test is. Elongation index and flakiness index of coarse aggregate bs 812. Flakiness indexflakiness index the flakiness index of aggregate is the percentage bythe flakiness index of aggregate is the percentage by weight of particles in it whose least dimensionweight of particles in it whose least dimension thicknessthickness is less than three.
Effect of aggregate flakiness on the compressive strength. The dimensions of slots of the apparatus used in your experiment and figured in your article is as follows. What various tests are done for the water, fine aggregates. Elongation index the elongation index on an aggregate is the percentage by weight of particles whose greatest dimension length is greater than 1. Astm d4791 19 standard test method for flat particles. Determination of the flakiness and the elongation index for the given aggregate. Flakiness and elongation index of coarse aggregate particle shape and surface texture influence the properties of freshly mixed concrete more than the properties of hardened concrete. Dec 12, 2017 flakiness and elongation index of coarse aggregate particle shape and surface texture influence the properties of freshly mixed concrete more than the properties of hardened concrete. Flakiness and elongation index of aggregate gilson co.
Pdf determination of the flakiness and the elongation index for. Flakiness index and elongation index of coarse aggregates. Determinations for the flakiness index and flakiness and elongation of aggregate use a british standard classification system consisting of a thickness gauge for determining flakiness index and a metal length gauge for determining elongation index. Definition the flakiness index of a coarse aggregate is the mass of particles. Index of a coarse aggregate scope the flakiness index of a coarse aggregate is determined by gauging screenedout fractions with the appropriate slots given in table i below. Angular aggregates increases flakiness or elongation thus reduces workability. Combined effect of flaky and elongated aggregates on. Round smooth aggregates require less water and less lubrication and greater workability in a.
Therefore, aggregate properties are very important in hma because it will affect the performances of the hma. The scope of this test is to provide test methods for determining the elongation index of coarse aggregate. Flakiness and elongation of aggregates and concrete properties published on december 6, 2016 december 6, 2016 27 likes 9 comments. The particle shape of the aggregate is determined by. It is expressed as the percentage by weight of particles in a sample of more than 200 whose smallest dimension is less than 0. Is the combined flakiness and elongation index of aggregate.
An aggregate is classified as being elongated if it has a. The test is performed on a sample of coarse aggregate reduced from a representative field sample. Elongation index and flakiness index of coarse aggregate bs. Regarding shape analysis of the coarse aggregate, only the flakiness and elongation are measured.
Flakiness index test is not applicable for aggregates sizes smaller than 6. It is measured on particles passing through mesh size of 63mm and retained on mesh size of 6. Elongation index and flakiness index of coarse aggregate bs 812 part. Geometrical requirements fines content the aggregate producer or supplier shall declare the class i. Aggregate is separated into seven sieve fractions from 636.
When an aggregate particle has a thickness less than 0. Elongation index is the percentage by weight of particles in it, whose largest dimension i. Elongation and flakiness index of coarse aggregate with 0%, 5%, 10%, 15%, 20 % and 25% and impurity of fine aggregate with 0%, 2%, 4%, 6%, 8 % and 10% were adjusted while the amount of stone, sand, cement and water weer kept unchange. The test is not applicable to sizes smaller than 6. The dried aggregates sample is allowed to passing and retained on a set of sieve. Report the elongation index in percentage rounded off to the nearest whole number. The procedures for their measurement are specified in bs812, section 105. The influence of combined flakiness and elongation indices on marshall properties of coarse aggregate with nmas 12.
Flakiness and elongation test of aggregate as per is 2386. Laserbased approach for determining flakiness index of aggregates used in pavements j anochieboateng, j komba and j oconnell csir built environment, bldg 2c, p o box 395, pretoria, 0001, south africa. Quarter the aggregate sample to obtain a minimum of 200 particles passing the 78in. Chapter 2 bituminous tex224f, determining flakiness index manual of testing procedures 1 899 1004 tex224f, determining flakiness index overview effective date. This method is based on the classification of aggregate particles as flaky when they have a thickness smallest dimension of less than 0. The particle is considered as elongated if its length is more than 1. The aggregate to be classified is separated into seven sieve fractions from 6. In this video, i had given full detail practical procedure of determining flakiness and elongation index of coarse aggregate. Roughtextured, angular, and elongated particles require more water to produce workable concrete than smooth, rounded compact aggregate. Definition of flakiness index and elongation index civil. Effects of aggregate properties on concrete like shape and surface texture affects usually the properties of freshly mixed concrete. Elongation index of an aggregate is the percentage by weight of particles whose greatest dimension length is greater than one and fourfifth times 1. The flakiness index is taken as the total weight of the.
Aggregate particles are classified as elongated when they have a length greatest dimension of more than 1. Objective for determination of flakiness index of coarse aggregate, where the size of the coarse aggregate are larger than 6. Flakiness index is the percentage by weight of particles in it, whose least dimension i. Methods of test for aggregates for concrete, part i. Aggregate quality for road construction will also influence the road performance. This procedure discusses how to determine the number of flat or elongated particles in a coarse aggregate material. The influence of the shape of the coarse aggregate on some. Dec 06, 2016 flakiness and elongation of aggregates and concrete properties published on december 6, 2016 december 6, 2016 27 likes 9 comments. This work aims at establishing the same quantitatively. In order to determine the effect of flakiness index on the bituminous mix, a number of aggregate test samples have to be prepared and upon each group of samples a certain percentage of flaky aggregate is applied which start from 0 to 5, 10, 15, 20, 25 %. Retained on flakiness percentage of bakiness index. Doc flakiness index and elongation index of coarse.
Flakiness and elongation flakiness index sieve set uta0410. Aug 11, 2014 the flakiness index test fi is not applicable passing 6. Elongation value is 0% because the aggregate is rounded so no any retain value. The particle shape of aggregates is determined by the percentages of flaky and elongated particles contained in it. Effects of aggregate properties on concrete size, grading. Combined effect of flaky and elongated aggregates on strength and workability of concrete has often been qualitatively expressed. Shape tests on coarse aggregates such as flakiness index and elongation index, its importance in. The flakiness index of course aggregate is defined in percentage by weight of aggregate particles and least dimension thickness of those particles should not be less than 0. Aggregate are the important constituent in concrete. For pavements either bituminous or nonbituminous, elongation index of coarse aggregate should not be more than 15%. Aggregate retained on the 75 mm and passing the 4,75 mm sieve is not included in the test. Flat and elongated particles of coarse aggregates have a tendency to fracture more easily than other aggregate particles.
Bulk density and voias of coarse aggregate duration. Objective for determination of elongation index of coarse aggregate, where the size of the coarse aggregate are larger than 6. Individual aggregates of specific sieve sizes are tested for ratios of width to thickness, length to width, or length to thickness. The elongation index is not applicable to sizes smaller than 6. Two procedures, method a and method b, are presented in this standard. The elongation index is the total weight of the material. Following tests are conducted on coarse aggregates under shape tests. The percentage by weight of the elongated particles present in a given test sample. The apparatus for the shape tests consists of the following. What is the significance of flakiness index and elongation index.
Method a is a reflection of the original procedure as developed prior to superpave and is intended for all nonsuperpave applications. The flakiness index test fi is not applicable passing 6. Flat particles, elongated particles, or flat and elongated particles in coarse aggregate astm d 4791 glossary flat and elongated particles of aggregate those particles having a ratio of length to thickness greater than a specified value. Flakiness index sieve set uta0410 when an aggregate particle has a thickness less than 0.
This video will help you to learn how to check flakiness and elongation percentage in coarse aggregate, for. Mar 03, 2012 elongation value is 0% because the aggregate is rounded so no any retain value. How to improve flakiness index on a aggregate crushing plant. Exp 1 flakiness and elongation index civil engineers pk. The test is carried on aggregate sizes between 63 mm and 6. Elongation index is the % by weight of particles whose greater dimension is greater than 45 of the mean dimension. Shape tests on coarse aggregates such as flakiness index and elongation index, its importance in concrete construction, methods of determination is discussed. The weight of retained aggregate on each sieve is measured and determined the percentage of retained. Flat or elongated aggregate particles can, if present in sufficient number, 1 impede compaction or 2 affect hma behavior by fracturing during compaction.
For determination of flakiness index of coarse aggregate. Angular shape of the particles is desirable in granular base coarse flexible. Subsequently slump index and compressive strength of concrete were determined. Flakiness and elongation index of aggregate youtube. Sep 09, 2017 flakiness and elongation test of aggregate as per is 2386 part 1, content aggregator. What is the significance of flakiness index and elongation. Use this test method to determine the percentage of particles in a coarse aggregate. Aggregate are granular material, derived from the most part from the natural rocks, crushed stones, or natural gravels and sands. It is intended that bs812 test methods should be called up by other british standards as the basis of compliance. For determination of flakiness index of coarse aggregate, where the size of the coarse aggregate are larger than 6.