COMPRESSIVE STRENGTH OF M25 GRADE CONCRETE BY USING RECYCLING AGGREGATES by IRJET Journal

COMPRESSIVE STRENGTH OF M25 GRADE CONCRETE BY USING RECYCLING AGGREGATES

Dr. G. Hathiram1, B.Sriharish2, Md.Younus Ali Khan3, B.Sahithi4, Sk.Khadeer5

1 Asso. Prof. & HOD, Dept of Civil Engg, KLR College of Engg & Technology, Paloncha, Telangana, India.

2 Assi. Prof., Dept of Civil Engg, KLR College of Engg & Technology, Paloncha, Telangana, India.

3,4,5 B.Tech Final Year, Dept of Civil Engg, KLR College of Engg & Technology, Paloncha, Telangana, India ***

ABSTRACT:

Concrete that contains recycled aggregate can help to safeguard the environment by controlling the depletion of natural aggregates (1) The building materials of the future are recycled aggregates (2). Many countries around the Globe, have started the usage of Recycled coarse aggregates (RCA) in place of naturally available aggregate. The basic characteristics of recycled fine aggregate and recycled coarse aggregate are reported in this work. All aggregate qualities undergo fundamental alterations, and their implications for concrete work are thoroughly have to be examined. The characteristics of concrete with recycled aggregate are also established. Compressive strength for various combinations of recycled aggregate with natural aggregate is studied Workability for the various mixes used is also presented

INTRODUCTION:

Concrete is the most frequently utilized man-made construction material in the world. It is made by combining water, fine aggregates, coarse aggregates, cement, and occasionally admixtures in the proper ratios. Fresh concrete, also known as plastic concrete, is a substance that has just been mixed and is capable of taking on any shape before hardening into what is known as concrete. A long-lasting chemical reaction between water and cement causes the hardening, which makes the cement stronger over time. The endurance and aesthetic appeal of concrete constructions made with regular Portland cement during the first half of the 20th century (OPC) Contempt has been fostered by the accessibilityofthecomponentsofconcrete,regardlessof their characteristics, as well as the awareness that almost any combination of the components results in a mass of concrete. Without giving structures' longevity any regard, emphasis was placed on strength. The durability of concrete and concrete structures is declining as a result of the liberties taken; this decline appears to be gaining speed as it heads towards selfdestruction.Thisisespeciallytrueofconcretestructures built after 1970 or so, around the time that the next

advancements began to occur. The use of high strength rebars with surface deformations (HSD) started becoming common. Significant changes in the constituents and properties of cement were initiated. Engineersarestartedusingsupplementarycementitious materials (SCM) and admixtures in concrete, often without adequate consideration. The Ordinary Portland Cement(OPC)isoneofthemainingredientsusedforthe productionofconcreteandhasnoalternativeinthecivil construction industry. Unfortunately, in the production of cement involves emission of large amounts of carbondioxide gas into the atmosphere, a major contribution for greenhouse effect and the global warming. To safeguard our environment, it is therefore necessary to either look for alternative materials or partially replace existing ones. The quest for any such cementitious material that can be utilized in place of or inadditiontocementshouldresultinthelowestpossible environmental effect and worldwide sustainable development.

1. EXPERIMENTAL INVESTIGATION:

From the past research studies it is discovered that several pozzolanic materials, such as fly ash, ground granulatedblastfurnaceslag(GGBS),ricehuskash,high reactive Metakaolin, and silica fume, can be used in concrete as a partial replacement for cement. Many studiesinvestigatingtheeffectsofusingthesepozzolanic materials are ongoing both in India and overseas These materials can be used in concrete as a partial replacement for cement because of their properties similar to cement. Studies on the effects of using these pozzolanic materials as cement substitutes are now being conducted both in India and overseas, and the findings are promising. The characteristics of the components,mixpercentage,compactiontechnique,and other factors that are controlled during placement and curing determine the strength, durability, workability, and other characteristics of concrete. Several factors contribute to these demands, but as engineers, we must consider how durable the constructions made of these materials will be been able to meet the needs whileputtinglong-termdurabilityconcernstooneside.

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RCA is often used as a base material for roads, parking lots, and other construction projects. It can be used in place of gravel or other natural materials. RCA can be used in structural applications, such as concrete beams, columns,and walls.Itcanalsobeusedtocreate precast concrete elements, such as pavers and blocks. RCA can beusedasadecorativematerialinlandscapingprojects. Itcanbeusedtocreateretainingwalls,gardenbeds,and other features. RCA can be used as a drainage material, helping to prevent water buildup in areas prone to flooding.

The need for concrete with a high strength is now unavoidable due to the building industry's shift to precastpartsandthedemandforpost-tensioning.Engineers had to find a way to get around these challenges, which we have largely succeeded in doing. But today's construction sector aims to save money through both concrete and financial factors. Used in the building of kerbs, sat gutters, and precast concrete. Saving money: Concrete is unaffected, and it is anticipated that the cheaper price of recycled concrete aggregate will more thanmakeupforthehighercostofcement(RCA).Alkali silica reaction is discovered to be controlled by 20% fly ash replacement of cement (ASR).It is environmentally friendly and there is less travelling and no resource extraction.Hence,lesslandisneeded.Aboutsavingtime there is no need to wait for the availability of the material. Less crushing results in lower carbon emissions. For all concrete with a typical strength of 65MPa or less, up to 20% of natural aggregate can be replaced with RCA or recycled mixed aggregates (RMA) without the requirement for extra testing., as per Dutch standardVBT1995,ispermitted.

1.2 Materials:

1.2.1 Cement: Cement is a material that has cohesive andadhesiveinthepropertiesinthepresenceofwater.

Table:1 Properties of ordinary Portland cement

Table:2 Chemical properties of cement:

S.NO Characteristics Result(0% by mass)

1.2.2 Fine aggregate:

Fine aggregates are materials passing through an IS sievethatislessthan4.75mmgauge.

Table:3 Properties of fine aggregates:

Table:4 Sieve analysis of fine aggregate (weight of sample 1000g)

1.2.3 Coarse aggregate: Coarse aggregates are materialswhichretainsonanISsieve4.75mmgauge.

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Properties Results obtained Specificgravity 2.74 Waterabsorption 0.8% Finenessmodulus

2.47

S. L N O IS Sieve size Weight retaine d (g) Cumulati ve weight retained Cumulative %weight retained (g) Cumula tive% passing 1 10mm 0.00 0.00 0.00 100.00 2 4.75m m 10.00 10.00 1.00 99.00 3 2.36m m 46.50 56.50 5.65 94.35 4 1.18m m 188.00 24.50 24.45 75.55 5 600m m 288.00 532.50 53.25 46.75 6 300m m 358.00 890.50 89.005 10.95 7 150m m 109.00 1000.00 100.00 0.00 Finenessmodulusofsand=(273.35/100) =2.73

Fineness 340m2 /Kg Specificgravity 3.10 Initialsettingtime(min) 42 Finalsettingtime(min) 190

1 Lossofignition

2 Silica(sio2) 2.27 3 Alumina(al2O3) 4.42 4 Iron(fe2O3) 11.38 5 Calcium(cao) 58.51

3.15

Recycled coarse aggregate (RCA) is a type of construction material that is made by crushing and recycling concrete waste. It is an environmentally friendly alternative to traditional coarse aggregates that are typically made from natural resources such as rocks and gravel. Recycled coarse aggregate refers to the processedandreusedconstructionwastethatconsistsof crushed concrete, bricks, tiles, and other demolition debris. The process of recycling coarse aggregate involves breaking down and crushing the waste materials into smaller pieces that meet specific size and quality requirements for use in new construction projects. Recycledcoarseaggregatehasseveral benefits, includingreducingtheamountofwastesenttolandfills, conserving natural resources, and reducing the carbon footprintofconstructionprojects.Additionally,itisoften moreaffordablethanusingvirginmaterials,makingitan economicalchoiceforconstructionprojects.

2. CASTING AND COMPACTION OF TEST SPECIMENS:

The cube moulds shall be 150mm x 150mm x 150mm size confirming to IS 10086-1982 are cleaned and all care was taken to avoid any irregular dimensions. The joints between the sections of moulds were coated with mould oil and a similar coating to prevent water from escapingduringfilling,mouldoilwasplacedbetweenthe contact surfaces of the base plate and the bottom of the moulds. Mold oil was lightly applied to the inside surfaces of the moulds to avoid concrete adherence and tofacilitatesimplemouldremovalfollowingcasting.The mouldsarethensetupontheplaincastingplatform.

The specimens of Standard cube moulds (150mm x 150mm x 150mm) placed in trays and the mixed concrete poured in to specimen moulds in three layers andcompactedwithatamperedrodthoroughlytoreach required shape and compaction. By this way we have casted 360 no. of cubes. These prepared cubes and prismswereplacedatplainleveledsurfacefor24hours.

Table: 7 Impact test tabular form:

Table: 8 Crushing test tabular form:

Properties

Specificgravity 2.74 Waterabsorption 0.4% Finenessmodulus 4.01

Table:5

of coarse aggregate:

S.L . NO IS Sieve size Weight retaine d(g) Cumulati ve weight retained Cumulati ve % weight retained (g) Cumulati ve % passing 1 80mm 0.00 0.00 0.00 100.00 2 40mm 0.00 0.00 0.00 100.00 3 20mm 3376.50 3376.50 67.52 32.487 4 10mm 1358.00 4761.00 95.22 4.78 5 4.8mm 169.00 4930.00 98.60 1.40 6 2.4mm 70.00 5000.00 100.00 0.00 7 1.18m m 0.00 5000.00 0.00 0.00 8 600m m 0.00 5000.00 0.00 0.00 9 300m m 0.00 5000.00 0.00 0.00 10 150m m 0.00 5000.00 0.00 0.00 Fineness modulus of coarse aggregate = ∑g/100 =36.1/100 =3.61

Table:6 Sieve analysis of coarse aggregate( weight of sample 5000g )

SL.N O Type of aggrega te Weight of aggrega te with mould Weight of aggrega te Passing througho ut 2.36mm Retain ed in pan 1 10mm 2193gm s 650gms 73gms 577gm s 2 10mm 2157gm s 614gms 80gms 534gm s 3 10mm 2182gm s 639gms 104gms 535gm s

SL.N O Type of aggreg ate Weight of aggreg ate with mould Weight of aggreg ate Passing through out 2.36mm Retain ed 1 10mm 13.5kgs 4.5kgs 1.2kgs 3.4kgs 2 10mm 13kgs 4kgs 0.8kgs 3.2kgs 3 10mm 13kgs 3.7kgs 1.2kgs 2.5kgs

3. WORKABILITY OF VARIOUS CONCRETE

4.

On the date of testing i.e., after 7,14,21 days casting of thecubespecimenswereremovedfromthewatersump and placed on flat surface for 15 to 20 minutes to wipe off the surface water and grit, and also remove the projecting fineness on the surface of the cured cubes. Beforeplacingthecubesincompressiontestingmachine thebearingsurfaces(topandbottomofthecompression testing machine was wiped clean with a piece of cotton or fine brush, and the cube specimens also cleaned. The cube specimen was placed in the compression testing machine (CTM) of 2000KN capacity. The load was applied approximately 150kg to 200k/sq.cm/min until the resistance of the cube. The applied load is gradually increased until the cube is failed. The maximum load is recorded when the cube was collapsed. By dividing the greatest load applied to the specimen during the test by thecrosssectionalareaofthespecimen,thecompressive strength of the cube was computed average of three values of three cubes and the individual variation is more than 15% of the average was observed. The test resultsarepresentedinTable.

Compressivestrength(C)=P/A.

Compressivestrength(C)=Load/Area

Where,P=maximumappliedloadinNewton's

A= area of cross section of cube in mm2 (150mm×150mm)

Table: 9 Slump cone test tabular form:

MIX ID SLUMP (mm) C100 90 C80 85 C70 90 C60 80 C50 80

MIXES: TEST FOR COMPRESSIVE STRENGTH OF CONCRETE:

MIXID Natural aggregates Recycled aggregates 7Days 14Days 21Days C100 0 100 32.68 46.8 54.87 C70 30 70 34.2 46.98 56.8 C60 40 60 36.5 50.2 60.3 C50 50 50 31.8 44.3 54.2 C40 60 40 25.44 39.8 48.2 C30 70 30 22 35.4 42.13 Degreeof workabil ity Slump Compacting factor Use for which concrete is suitable Mm In Verylow 0-25 0-1 078 Very dry mixes; used in road making. Low 2550 1-2 085 Low workability mixes; used for foundations with light reinforcement. Medium 50100 2-4 092 Medium workability mixes; normal reinforced concrete manually compacted and heavily reinforced sections with vibrations. High 100175 4-7 095 High workability concrete; for sections with congested reinforcement

Table: 10 Compressive strength of concrete for different percentages by recycled aggregate M25 grade

4. CONCLUSIONS:

Based on experimental investigations the following conclusionsaredrawn.

1. The use of recycled aggregate has been found to be betterthanthatofnaturalaggregate.

2. When being broken down into smaller pieces, a significant amount of carbon dioxide is absorbed, loweringtheatmosphericconcentrationofCO.

3. The physical properties of recycled aggregates make them ideally suited for road base and sub-base. This is due to their physical characteristics, which require less cement, making them suitable for use as sub-bases. In addition, developers often benefit financially from the process.

4. From the figure1, the variation of compressive strength with different coarse aggregates to RCA proportions is studied for 7days, 14days and 21days, andispresentedbelow.

7Days;y=22.768x0.269 , , R2 =0.7373

14Days;y=38.0.14x0.1501 ,R2 =0.6629

21Days;y=43.184x0.1763 ,R2 =0.8118

5. REFERENCES:

1 https://doi.org/10.1016/j.cemconcomp.2018.03.008

2. https://doi.org/10.1016/B978-0-08-1026168.00003-4

3. M. Collepardi, "Admixtures used to enhance placing characteristics of concrete" Cement & Concrete Composite,Vol.20,1998,103-112

4. S. Bhanja, B. Sengupta, "Modified water cement ratio law for silica fume concretes", Cement and Concrete Research.Vol33.2003.447-450.

5. IS 456: 2000, "Indian Standard Code of Practice for Plain and Reinforced Concrete", Bureau of Indian Standard,NewDelhi.

6. IS 10262: 2009 "Recommended Guidelines for Concrete Mix Design", Bureau of Indian Standard, New Delhi.

7. IS 383: 1970, Specification for Coarse Aggregate and Fine Aggregate From Natural Sources for Concrete", BureauofIndianStandardNewDelhi.

8. IS 9103: 1999, Indian Standard Concrete Admixture Specification" Bureauof IndianStandard,NewDelhi.

IS Codes:

1) IS 456-2000 code of practice for plain & reinforced cementconcrete.

2) IS 10262-2009 recommended guide line for concrete mixdesign.

3)IS12269-1987SpecificationforOPC53grades.

4) IS 3 83-1970 Specification for coarse aggregate and fineaggregatefromnaturalsources.

5) IS 650-1966 Specification for standard sand for testingofcement.

FIGURE 1:Compressivestrengthofconcretefordifferentpercentagesbyrecycledaggregates

y7D = 22.768x0.269 R² = 0.7373 y14D = 38.014x0.1501 R² = 0.6629 y 21D= 43.184x0.1763 R² = 0.8118 0 10 20 30 40 50 60 70 C30 C40 C50

compresssive strength, MPa Mix proportions 7Days 14Days 21Days Power (7Days) Power (14Days) Power (21Days)

C60 C70 C100