Elongation index the elongation index on an aggregate is the percentage by weight of particles whose greatest dimension length is greater than 1. Pdf shape and grading of aggregates can influence concrete workability. Coarse aggregate may be available in several different size groups, such as 19 to 4. It is known that the aggregates from domestic natural resources have negligible absorption, up to 1% as maximum, while the value of the classically recycled coarse aggregate typically ranges within the interval from 3. As expected, a lightweight aggregate will have a lower modulus than.
The physical properties of aggregates stem from the inherent properties of the source rock. Aggregates coarse aggregates 5 mm fine aggregates properties of aggregates must be known before mixing concrete to obtain a desirable mixture. The elongation index is not applicable to sizes smaller than 6. Pdf study of coarse aggregate characteristics on strength. Aggregates consisting of materials that can react with alkalies in cement and cause excessive expansion, cracking and. These fracture properties are heavily dependent on the components in the mixture, with fracture energy depending largely on the quality of the itz and the properties of the coarse aggregate. The experimental results show that the mixture slump, splitting tensile strength, flexural strength, initial flexural toughness ratio, flexural toughness ratio, fracture energy and. There are several reasons for specifying grading limits and nominal maximum aggregate size.
Structural lightweight aggregatestructural aggregate meeting the requirements of astm c 330 with bulk density less than 70 lbft. Effects of aggregate size, shape, and surface texture on the. Coarse aggregate is mined from rock quarries or dredged from river beds, therefore the size, shape, hardness, texture and many other properties can vary greatly based on location. Aggregate aggregate is a broad category of coarse particulate material used in construction, including sand, gravel, crushed stone, slag, recycled concrete and geosynthetic aggregates. Physical properties the physical properties of aggregates are those that refer to the physical structure of the particles that make up the aggregate. It should be sharp, course and angular to have good interlocking property. Examples of classes of concrete aggregate are shown below.
Hence, this study presents the initial physiochemical characterization and comparison of the virgin aggregate properties, with those of locally available rca as a sustainable alternative. As all the other variables were kept constant, this research enabled us to determine the influence of the coarse recycled aggregate amount 0%, 50% and 100% on. For recycled coarse aggregate, the parent concrete is crushed through a mini jaw crusher maintaining the size of aggregate between 20 and 4. Two different arrangements have been used to determine the shear. The detailed data on properties of these materials are reported elsewhere 14. The strength of aggregates do not contribute to the strength of concrete for low strength concrete. Aggregates are inert fillers floating in the cement paste matrix for concretes of low strength.
Materials utilized for this project consisted of cfa, cement, fine aggregate, coarse aggregate, and coal fly ash. Fine aggregates generally consist of natural sand or crushed stone with most. Typically, coarse aggregate sizes are larger than 4. The current manuscript presents a detailed study on physical properties of aggregates procured from all seventeen districts in gujarat. Enhancement of properties of recycled coarse aggregate. Some variation in the type, quality, cleanliness, grading, moisture content, and other properties is expected. Test and analyses has been carried out to establish relationships among the compressive strength, split tensile strength and shear strength of concrete using recycled coarse aggregate. Although inclusion of seashell aggregate reduces the physicomechanical properties of concrete, utilising some seashells as partial coarse aggregate at up to 50% substitution level can produce. Each material was characterized for physical and chemical properties in accordance with the appropriate astm standards. Aggregate sampling aashto t 2 sample preparation aashto t 248 aggregate gradation of both fine and coarse aggregates aashto t 27 wash loss determination of minus no. Natural sand, crushed stone dust or manufactured sand by crushing rock. Close to half of the coarse aggregates used in portland cement concrete in north america are gravels.
Material passing 75 m sieve should not be 4% by weight. An investigation of mechanical properties of recycled coarse. Coarse aggregate types properties bricks chips stone chips maximum size mm 12. Kaplan 1959 studied the effects of the properties of coarse aggregates on. Aggregates are divided into two categories from the consideration of size i coarse aggregate and ii fine aggregate. Sand, surki, stone screenings, burnt clays, cinders, fly ash, etc are used as fine aggregate in. Sep 03, 2017 the final properties of the concrete will depend on the cement characteristics, the type and amount of aggregate, the watercement ratio, and the completeness of the reaction subject to time, humidity, and temperature. Coarse aggregate typically occupies over onethird of the volume of concrete, and research indicates that changes in coarse aggregate can change the strength and fracture properties of concrete.
Making a sieve analysis test of coarse aggregate in a laboratory. Range of particle sizes found in aggregate for use in concrete. A higher aggregate modulus will result in a concrete having a higher modulus. Physical properties of aggregates 7 coarse aggregate angularity traffic depth from surface esals 100 mm. The present study focuses on the effects of microsilica at various percentages as a partial cement replacement in concrete with overburnt bricks as coarse aggregates. Aggregates for concrete e sieve and predominantly retained on the 75 m no. Difference between fine and coarse aggregate civil engineering.
The crushed stone or crushed gravel aggregate make the asphalt or concrete mix somewhat difficult to place. Properties of concrete with coconut shells as aggregate replacement 22 2. Concrete is by far the most versatile and most widely used construction material worldwide. It should not contain any organic and other admixtures. The following tests are required for basic understanding of aggregate properties. The purpose of the fine aggregate is to fill the voids in the coarse aggregate and to act as a workability agent. Strength properties of concrete containing coconut shell as. Concrete 1 concrete a composite material that consists essentially of a binding medium, such as a mixture of portland cement and water, within which are embedded particlesorfragmentsofaggregate,usuallyacombination of. Properties of aggregates and its values for use in construction. Recycled concrete as aggregate for structural concrete production. The quality and fine aggregate density strongly influence the hardened properties of the concrete.
It is well recognized that coarse aggregate plays an important role in concrete. Mix proportions in order to investigate properties of cs concretes, six mixes were employed. The aggregates are usually washed and graded at the pit or plant. Properties of selfcompacting concrete with recycled coarse. Mixtures in which the coarse aggregate predominates and in which fines are insufficient to fill the coarse. Aggregate particles have certain physical and chemical properties which make the aggregate acceptable or unacceptable for specific uses and conditions. Some physical properties of cement, gp, mk, fine aggregate and coarse aggregate. Pdf mechanical properties of concrete with recycled. Properties of aggregates construction aggregate porosity.
Properties strength compressive strength tests aggregate crushing value aggregate impact value 10% fines value 12. Pdf assessment of physical properties of coarse aggregates in. Fine aggregates are the particles that pass through 4. However, the properties of the aforementioned virgin and recycled coarse aggregates were hardly ever systematically published. The properties of the coarse aggregate used in a concrete mixture affects the modulus for a few reasons. Properties of concrete using crushed brick as coarse aggregate. Coarse aggregates are larger size filler materials in construction. Coarse aggregate was then replaced with cs in 10 m2, 15 m3, 20 m4 percentages to study effect of cs replacement. This study investigated the effects of steel fiber length and coarse aggregate maximum size on mechanical properties of steel fiber reinforced concrete sfrc. In this paper, c25 waste road concrete is used as an experimental material, the uniaxial compression strength and tensile splitting strength of c25 rac whose coarse aggregate replacement rate is 0%, 25%, 50%, 75%, and 100% are tested under the condition that the watertocement ratio is 0.
The concrete or mortar mixture can be made more durable, stronger and cheaper if you made the selection of fine aggregate on basis of grading zone, particle shape and surface texture, abrasion and skid resistance and absorption and surface moisture. It should be free from silt, clay and coal residues. Vdot would need to implement a strengthbased cta design to be able to use the required mechanical properties of cta. Properties of aggregates also has effect on resulting concrete.
Feb 01, 2014 aggregate generally occupy about 70% to 80% of the volume of concrete and can therefore be expected to have an important influence on it properties. To improve the workability, many mixes contain both angular and round particles. One property is the modulus of elasticity of the coarse aggregate. A maximum size up to 40 mm is used for coarse aggregate in most structural applications, while for mass concreting purposes such as dams, sizes up to 150 mm may be used. Crushed aggregate have irregular, angular particles that tend to interlock when compacted or consolidated. The coarse aggregate particles are usually crushed stone or crushed gravel, and the fine aggregate particles are usually natural sand. Physiochemical characterization of coarse aggregates in qatar. Coarse aggregates are the particles that retain on 4. Effects of steel fiber length and coarse aggregate maximum. The volumes of water for well graded and poorly graded vary along. Textural properties give rise to internal characteristics, of which the pore size is perhaps most important.
Bulk density kgm3 mechanical properties toughness resistance of aggregate to failure by impact aiv. Aggregates types of aggregates coarse aggregate, fine. Aggregates aggregates generally occupy 65 80% of a concretes volume. It should be free from thin, flat elongated flaky or splinter. Properties of concrete with coconut shells as aggregate. Balanced mixtures of coarse and fine aggregateare referred to as denseraded mixtures or bituminous concretes, finegraded for maximumsize aggregate of 2 in. Research article properties of selfcompacting concrete with.
The characteristics of aggregates impact performance of fresh and hardened. This includes aggregates prepared by expanding, pelletizing, or sintering products such as blastfurnace slag, clay, fly ash. The aggregate crushing value of coconut shell is 3. Structural characteristics define the degree to which the minerals within the aggregate are segregated or oriented in one. Pdf assessment of properties of recycled coarse aggregate. The elongation index is the total weight of the material. Twentytwo types of selfcompacting highperformance concrete made by coarse natural aggregate and coarse recycled concrete aggregate have been crushed and their properties have been studied. Determination of mechanical properties for cement treated.