Flakiness and elongation index of aggregate youtube. The flakiness index test fi is not applicable passing 6. The elongation index of an aggregate is the percentage by weight of particles whose greatest dimension. This process is carried out when the aggregate proportions such as coarse, fine and dust is identified. Determination of flakiness index of the coarse aggregate. Aggregate elongation index tests open geotechnical. When the coarse aggregate does fracture, the gradation will likely change which may be detrimental to the mix.
Aggregate crushing value crushingtest of coarse aggregate duration. Dry density of soil compaction test by core cutter method and calculations road construction civil. Proportional calipers are efficient devices that quickly determine percentages of elongated and flat particles in coarse aggregate fractions. The effect of different percentages from 0 to 50% of combined flaky and elongation aggregates cfea for quality concrete on the compressive and flexural strength of cement concrete is studied. Aggregate is separated into seven sieve fractions from 63. Theory of flakiness index and elongation index tests the particle shape of aggregates is determined by the percentages of flaky and elongated particles contained in it. The mra provides the distribution of shape in an c h a p t e r 4 conclusions and suggested research aggregate sample, but it cannot be used for measuring angu larity or texture. Lab equipments flakiness manufacturer from ahmedabad.
Flakiness and elongation indices of coarse aggregate youtube. Is the combined flakiness and elongation index of aggregate is the numerical sum of separate elongation index and flakiness index. Flakiness sieves, aggregates testing equipment, controls. Methods of test for aggregates for concrete, part i. Elongation index test on coarse aggreagtes the constructor. Easily share your publications and get them in front of issuus. An aggregate is classified as being elongated if it has a.
Elongation index and flakiness index of coarse aggregate bs 812. Important shape test, flakiness and elongation index test is discussed here. The length gauge elongation index bs, is used to measure the elongation index of aggregates. As the percentage of laterite increases, there was a reduction in all these characteristics even with the particle size of coarse aggregate reduction due to loss from the aggregate paste interface zone. This british standard, a section of the bs 812 series, describes methods for determining the flakiness index of coarse aggregate. Determination of the flakiness and the elongation index. Now, you need to find the amount of elongated particles to the aggregates which passed flakiness test. For measuring the coarse aggregate shape only, the multiple ratio shape analysis method mra is most desirable, and is much cheaper than all the other test methods. In case of gravel it is determined by its angularity number. Flakiness index test is not applicable for aggregates sizes smaller than 6. The consumption of cement with an increase of the size of the aggregate from 40 to 80 mm, other conditions being equal, decreases by 20. Elongation index of an aggregate is the percentage by weight of particles whose greatest dimension length is.
Dec 18, 2017 theory elongation index aggregate particles are classified as elongation when they have a length greatest dimension of more than 1. Determination of the flakiness and the elongation index for the given aggregate sample. Flakiness index and elongation index of coarse aggregates. Conclusion based on the objective for this experiment is to identify the flakiness and elongation index of the given aggregrate samples, we indentified the flakiness and elongation is not influenced each other. Determination of elongation index linkedin slideshare. Elongation index of an aggregate is the percentage by weight of particles whose greatest dimension length is greater than one and fourfifth times 1. Aggregate to be classified is separated into seven sieve fractions from 63 to 6. Hence we offer thickness gauge and length gauge to check flakiness and elongation index of the aggregate respectively. Objective particle shape and surface texture influence the properties of freshly mixed concrete more than the properties of hardened concrete.
Elongation index is the percentage by weight of particles in it, whose largest dimension i. Aggregate retained on the 75 mm and passing the 4,75 mm sieve is not included in the test. Elongation test and flakiness tests are known as shape tests and are performed on aggregate. After weighing, the flakiness index is calculated as the ratio of the mass of flaky particles to the total mass of the aggregate sample expressed as a percentage. Definition of flakiness index and elongation index civil. What is the use of the elongation and flakiness index. To study the strength characteristics of concrete by. Such particles make poor concrete, since they are hard to compact, and e. Shape indices such as an elongation index and a flakiness index were.
Objective for determination of flakiness index of coarse aggregate, where the size of the coarse aggregate are larger than 6. It is mentioned in the test procedure bismorth that while doing combined flakiness and elongation test, the flaky aggregates should be separated initially. Coarse aggregate having flakier particles will adversely affect the strength of concrete. In this video, i had given full detail practical procedure of determining flakiness and elongation index of coarse aggregate. Conclusions and suggested research the national academies press. Roughtextured, angular, and elongated particles require more water to produce workable concrete than smooth, rounded compact aggregate. The particle is considered as elongated if its length is more than 1. For impact crushed a1 coarse aggregates slump values were evaluated for all five groups and it was evident from experiment that, there was a steady decrease in slump value with the decrease of wc ratio. Elongation index is the % by weight of particles whose greater dimension is greater than 45 of the mean dimension elongation index wt of aggregate retained on specified gauge total wt of aggregate taken. This british standard, a part of the bs 812 series, describes the method for determining the elongation index of coarse aggregate. Elongation index and flakiness index of coarse aggregate bs 812 part. What is the significance of flakiness index and elongation.
Flakiness and elongation flakiness index sieve set uta0410. Conclusions for the wide range of coarse aggregate stiffness used, combined with a single, high strength, low watercement ratio mortar, the following conclusions may be drawn. While elongation index test is used to determine the quantity of aggregate particles that are elongated instead of cubicle in shape. The other properties of aggregate such as bulk density, impact value, water absorption have been studied for different shapes of aggregates. To evaluete the thickness and the elongation index of the aggregates particles, thickness gauge code 47d0540 and length gauge code 47d0541 can be used. The percentage by weight of flaky particles present in a given test sample. Flakiness index is the percentage by weight of particles in it, whose least dimension i.
A decrease of the water requirement and content of cement and an increase of the density of concrete due to a decrease of the sand content and corresponding increase of the stony component are a positive aspect of increasing the size of the aggregate. The elongation index of an aggregate is the percentage by weight of particles whose greatest dimension length is greater than ninefifths 1. How to determine flakiness index and elongation index test. Elongation index for classification of aggregate particles. Flakey particles are those which are generally thin compared to their major dimensions. The flakiness index of an aggregate sample is found.
What is the significance of flakiness index and elongation index. Objective for determination of elongation index of coarse aggregate, where the size of the coarse aggregate are larger than 6. Shape tests on coarse aggregates such as flakiness index and elongation index, its importance in concrete. Oct 09, 2015 detailed video on laboratory experiments with subtitles. Subsequently slump index and compressive strength of concrete were determined. Pdf aggregate shape is considered to be a key parameter for concrete and bituminous mixtures design. The aggregate strength is usually not a factor except in lightweight and high strength concrete.
Aggregate quality for road construction will also influence the road performance. Click here to go to elongation test flakiness index test is used to determine the particle shape of the aggregate and each particle shape being preferred under specific conditions. 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. Bulk density and voias of coarse aggregate duration. The elongation and flakiness test involves sieving the aggregates through a sieve with long parallel openings as shown in the diagram below which measures the amount of aggregates which are elongated which determines the flakiness index. Flakiness index and elongation index of coarse aggregates free download as word doc. T 39 the above result of elongation index is less than 30%, hence satisfactory. Aggregates which are flaky and elongated are detrimental to the higher. Retained on flakiness percentage of bakiness index. Issuu is a digital publishing platform that makes it simple to publish magazines, catalogs, newspapers, books, and more online. Particle is elongated when its length longest dimension is more than 1. Effect of the maximum size of coarse aggregate on the main. Aggregate particles are classified as elongated when they have a length greatest dimension of more than 1. Elongation value is 0% because the aggregate is rounded so no any retain value.
The test is carried on aggregate sizes between 63 mm and 6. Finally, you can have numerical sum of flakiness index and elongation index to get combined f. In bituminous mixtures, flaky aggregates make for a harsh mix and may also crack and break up during compacting by rolling. Standard test method for index of aggregate particle shape. Interlocking of the aggregate is inversely proportional to the flakiness index or the elongation index. The aggregate to be classified is separated into six sieve fractions from 6. 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. Mean size of aggregates is defined as the mean of two seive sizes, between which the particle is retained. The use of coal mill reject in the concrete industry may be a replacement of stone aggregate with advantages like. Unfortunately, this book cant be printed from the openbook. Flakiness and elongation index of aggregate gilson co. The particle shape of aggregate is determined by the percentages of flaky and elongated particles contained in it. Jul 31, 2015 flakiness and elongation index of aggregate bput digital learning resources.
Influence of crushed coarse aggregates on properties of concrete. Elongation index and flakiness index of coarse aggregate bs. Flakiness and elongation of aggregates and concrete properties. Aggregate determination of the resistance to wear microdeval asdi. Additionally, flat and elongated particles of aggregate, for some construction uses, may interfere with.
The aggregate to be classified is separated into seven sieve fractions from 6. Dec 06, 2016 flakiness and elongation of aggregates and concrete properties published on december 6, 2016 december 6, 2016 27 likes 9 comments chemist mina ataalla follow. Surface texture of coarse aggregates surface texture of the aggregates is the property of its surface that classifies it into polished or dull, smooth or rough. This standard specifies a method for determining the flakiness index of coarse aggregate that passes a sieve of aperture size 75 mm and that is retained on a sieve of aperture size 4 750 om. Basic points, apparatus, procedure, results and inference are discussed in detail in the simplest form possible. In order to determine the effect of flakiness index on the bituminous mix, a number of aggregate. While tested for gradation, the coarse aggregates ranged from uniform to gap graded. Determination of flakiness and elongation index of coarse. Elongation and flakiness test construction aggregate. The scope of this test is to provide test methods for determining the elongation index of coarse aggregate. It is measured on particles passing through mesh size of 63mm and retained on mesh size of 6. The elongation index is found by separating the elongation particles and expressing their mess as a percentage of the mass of sample tested.
Roughtextured, angular, and elongated particles require more water. Flakiness and elongation index, properties and testing of. Plot the grading of the aggregate on a aggregate gradation chart, mat 67. This method is based on the classification of aggregate particles as flaky when they have a thickness smallest dimension of less than 0. In this experiment, flakiness index was used as independent variables and other properties such as gradation are kept constant as far as their properties met the specification required for the asphalt mixture. Aggregate particles are classified as flaky when they have a thickness of less than 0. The maximum size of a wellgraded coarse aggregate of a given. Flat and elongated particles of coarse aggregates have a tendency to fracture more easily than other aggregate particles. 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. Is the combined flakiness and elongation index of aggregate. Part 2flakiness index article pdf available in materials and structures 391. Is the combined flakiness and elongation index of aggregate is the. Not so much different between both of the two values.
B elongation index test 1 sample of aggregates were prepared. Similarly, the particle is considered as flaky if its thickness is less than 0. If the amount of either the coarse or the fine aggregate thus obtained is substantially. Flakiness index and elongation index test on 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.
Conclusions and recommendations the national academies press. Aggregate is termed as flaky when its least dimension i. Each lightweight aggregate lwa used in this study had. For base course and construction of bituminous and cement concrete types, the presence of flaky and elongated particles are considered undesirable as these cause inherent. Determination of flakiness and elongation index of coarse aggregates posted on november 16, 2019 april 8, 2020 author admin comment0 575362 views hello friends, this is. Aggregate angularity flakiness elongation index gilson co.
Flakiness and elongation tests are not applicable to sizes smaller than 6. Flakiness and elongation of aggregates and concrete properties published on december 6, 2016 december 6, 2016 27 likes 9 comments. 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. The flakiness index of the aggregate is the percentage by weight of particles in it, whose least dimension thickness is less than three fifth of their mean dimension. The latter attained about 95% of its 28day value by 7 days and gained little at later ages. 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. Flakiness and elongation test free download as word doc. Particle shape analysis of coarse aggregate using digital.
In the flakiness test, the flaky particles are separated from each size fraction by manual gauging and their quantities measured by weighing. However, aggregate characteristics other than strength, such as the size, shape, surface texture, grading and mineralogy are known to affect concrete strength in varying degrees. The figure 1 depicts slum value of a1 coarse aggregates for all five groups. Aggregate is separated into seven sieve fractions from 636. A study on influence of shape of aggregate on strength and. What is the use of flakiness index in concrete road work. Adjustment of flaky aggregates flakiness index test is applicable on those aggregate sizes bigger than 6. Calculate the total flakiness index in percent as follows. Effect of coarse aggregate on elastic modulus and compressive.
The amount of flakiness is denoted by flakiness index. Draw a horizontal line at 50% passing from the vertical scale to intersect with the grading curve. Exp 1 flakiness and elongation index civil engineers pk. The dried aggregates sample is allowed to passing and retained on a set of sieve. Elongation index and flakiness index of coarse aggregate. The flakiness of aggregate is determined by measuring the thickness of individual particles. Quarter the aggregate sample to obtain a minimum of 200 particles passing the 78in. Paper open access related content effect of different coarse. To determine the flakiness index of the coarse aggregate. Cement concrete produced with natural and coarse aggregates.
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