The main objective was to explore the feasibility of incorporating recycled coarse aggregate in new concretes of similar or higher strength grades and mitigate the effect of the reduction in strength of recycled aggregate concrete by designing a proper mix. The bulk density reflects the volume taken up by the cement plus any air trapped between the p. Manual of aggregate and concrete testing1 introduction this manual is intended to supplement, not in any way to supersede, the variousastm test methods for sampling and testing aggregate and freshly mixed and hardened portlandcement concrete. Fill the cylindrical measure to overflowing by means of a shovel or scoop, the aggregate being discharged from a height not exceeding 5 cm above the top of the measure. If smaller sizes are also to be tested, they may be separated into the petrographic. Classification of aggregates based on shape and size such as coarse and fine aggregates are discussed here, aggregates are the important constituents of the concrete which give body to the concrete and also reduce shrinkage. Astm c127 15 standard test method for relative density. The higher the fm is, the coarser the aggregate is.
Higher the surface area, greater is the water demand to coat the particles and generate workability. Scmt4 las vegas, usa, august711, 201 6 effect of using recycled concrete as coarse aggregate on tensile and flexural strength of concrete. This gives accurate results as it takes into account the dry loose bulk densities of materials like sand and aggregate which varies based on the local source of the material. Coarse aggregates are particulates that are greater than 9.
Astm c12715, standard test method for relative density specific gravity and absorption of coarse aggregate, astm international, west conshohocken, pa, 2015. This standard is issued under the fixed designation c 127. Tr 111 introduction these methods of test are designed to determine the particle size distribution of fine and coarse aggregates. Mix proportions in order to investigate properties of cs concretes, six mixes were employed. Effect of using recycled concrete as coarse aggregate on. Difference between fine and coarse aggregate civil. Coarse aggregate made from coconut shells were used in proportions of 5%, 10%, 15%, 20%, 25%, 30% and 35% to replace coarse aggregate in conventional concrete. Aggregates may be broadly classi fied as natural or artificial, both with respect to source and to method of preparation. The cf and 818 charts for the wg and nwg combined aggregates are plotted in fig. The mix of coarse and fine particles within the material being tested, in conjunction with the proposed use of the material, determines which test. Coarse aggregate is also described by its bulk density, which is a property that can easily be tested in the laboratory. How to calculate quantities of cement, sand and aggregate. However, the required information on strength of coarse aggregates can be obtained from indirect tests. According en 12620 is fm calculated on the following sieves.
Properties of concrete with coconut shells as aggregate. Coarse aggregates all coarse aggregates a special requirement placed on all coarse aggregates deals with the restriction on the number of flat and elongated pieces. For testing, british standard bs 812 has specified the degree of compaction. The proportions of cement, sand, coarse aggregate and water plays an important role in determining the fresh and hardended properties of concrete. The proportion of sand to coarse aggregate can be readjusted among each other,to accommodate the dlbd properties of locally available material,thus ensuring a cohesive concrete mix.
Types of aggregates include coarse aggregate and fine aggregate. Digital images of coarse aggregate particles are captured with the camera and analyzed within the matlab software program environment with a macro developed and written for this project to. Typically the most common size of aggregate used in construction is 20mm. Experimental investigation of concrete using coconut shell. While we talk about the strength of coarse aggregates it refers to the crushing strength of the aggregate itself. 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. Dlbd method to determine material requirement for nominal concrete mix,to highlight importance of same. Coarse aggregate acts as inert filler material for concrete. Classification of aggregates as per size and shape coarse.
The mix design shows fine aggregate absorption to be 2% and coarse aggregate absorption to be 1%. Pdf standard test method for resistance to degradation. Aggregates types of aggregates coarse aggregate, fine. As the maximum size of coarse aggregate reduces, surface area of coarse aggregate increases. As we mentioned above, the main classification of aggregate is fine and coarse aggregate. A flat and elongated piece is defined as one having a ratio of length to thickness greater than five. The fine aggregate serve the purpose of filling all the open space in between the coarse particles.
Coarse aggregate typically occupies over onethird of the volume of concrete, and research indicates that changes in coarse aggregate can. The dlbd dry loose bulk densities method is an accurate method to. The nwg aggregates were developed by combining different proportions of size number 57 coarse aggregate and fine aggregates. When corresponding fine aggregate specific gravity and absorption are determined on minus no. Add water freewater shown on the mix design aggregate freewater for example, consider a concrete mix design that calls for 282pounds of water i. Some natural aggregate deposits, called pitrun gravel, consist.
How coarse aggregate affects mix design of concrete. Larger aggregate diameters reduce the quantity of cement and water needed because of its. Strength of coarse aggregates is difficult to measure. 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. Coarse aggregate was then replaced with cs in 10 m2, 15 m3, 20 m4 percentages to study effect of cs replacement.
Partial replacement of coarse aggregate with demolished. Scope the cleanness test provides an indication of the relative proportions of claysized material clinging to coarse aggregates or screenings. Note 1this sample preparation method is not applicable when performing a sieve. The voids between the coarse aggregate are filled up by fine aggregate. Sieve analysis of fine and coarse aggregate dotd designation.
The function of the coarse aggregate is to act as the main loadbearing component of the concrete. Natural sands and gravels are the product of weathering and the action of wind or water, while manufactured crushed fine aggregate and crushed stone coarse and fine aggregate are produced by crushing natural stone. 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. A study on the utilization of coconut shell as coarse. The surface area of coarse aggregate is less than fine aggregates. No%% if the spparcnt spcci6c gravity oniy ia rcquimd the opaztiom described in 2. Illinois test procedure 327 resistance of coarse aggregate to degradation by abrasion in the microdeval apparatus 77 hard copies uncontrolled. Smaller maximum size of coarse aggregate would require greater fine aggregate content to coat particles and maintain cohesiveness of concrete mix. Properties of concrete with coconut shells as aggregate replacement 22 2. Although coarse aggregate usually take about 30% of the overall self weight of concrete. Aggregate is a granular material, such as sand, gravel, crushed stone, crushed hydrauliccement concrete, or iron blastfurnace slag, used with a hydraulic cementing medium to produce either concrete or mortar. How to calculate cement, sand and aggregate required for 1. Comparative study of natural and recycled aggregate concrete. Measure the volume of the cylindrical metal measure by pouring water into the metal measure and record the volume v in litre.
Physical properties of aggregates rowan university. The dlbd dry loose bulk densities method is an accurate method to calculate cement, sand and aggregate for a given nominal mix concrete. So care should be taken while calculating the amount of cement, sand and aggregate required for 1 cubic meter of concrete. Manual of aggregate quality test procedures april 16, 2019 january 1, 2018 manual of aggregate quality test procedures iv of iv. The standard testing procedure for this is the american society of testing. The manual was prepared by committee c09 on concrete and concreteaggregates and has been accepted.
References california test 202 sieve analysis of fine and coarse aggregates california test 217. The test will be carried out by using metal cylinder having prescribed depth and diameter and the bulk density is to be. Classification of aggregate used in construction purpose. A coarse aggregates with higher bulk density, then it means few of the voids can be filled by using fine aggregates and cement. How much sand aggregate and cement is required to concrete. A larger size, 40mm, is more common in mass concrete. If there is an insignificant discrepancy between the original total. Fine aggregate the fine aggregate used for making mortar is silt and clay. Journal of the south african institution of civil engineering volume 56.
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