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International Journal of Research and Innovation (IJRI)

International Journal of Research and Innovation (IJRI)CELLULAR LIGHT WEIGHT CONCRETE BLOCKS WITH DIFFERENT MIX PRO-

PORTIONS

G.Deepa1, K. Mythili2, Venkata Ratnam3.

1 Research Scholar, Department of Civil Engineering, Aurora Scientific Technological and Research Academy, Hyderabad, India.2 Assistant professor , Department of Civil Engineering, Aurora Scientific Technological and Research Academy, Hyderabad, India.3 Associate professor , Department of Civil Engineering, Aurora Scientific Technological and Research Academy, Hyderabad, India.

*Corresponding Author:

G.Deepa, Research Scholar, Department of Civil Engineering, Aurora Scientific Technological and Research Academy,Hyderabad, India.

Published: July 25, 2015,Review Type: peer reviewedVolume: II, Issue : II

Citation: G.Deepa, Research Scholar (2014) "Cellular Light Weight Concrete Blocks With Different Mix Proportions"

INTRODUCTION

Global warming and Environmental pollution is now a global concern. Cellular Light Weight Technology blocks can be used as an alternative to the red bricks, to reduce Environmental pollution and Global warming.

It is produced by initially making slurry of Cement + Fly Ash + Water, which is further mixed with the addition of pre-formed stable foam in an ordinary concrete mixer under ambient conditions. The addition of foam to the concrete mixture creates millions of tiny voids or cells in the material, hence the name Cellular Concrete.

Bricks remain one of the most important building materi-als in the country. Brick making is a traditional industry in India, generally confined to rural areas. In recent years, with expanding urbanization and increasing demand for construction materials, brick kilns have to grow to meet the demand. It has directly or indirectly caused a series

of environmental and health problems. At a local level (in the vicinity of a brick kiln), environmental pollution from brick-making operations is injurious to human health, animals and plant life. At a global level, environmental pollution from brick-making operations contributes to the phenomena of global warming and climate change. Also, extreme weather may cause degradation of the brick sur-face due to frost damage.

CLC blocks are environment friendly. The energy con-sumed in the production of CLC blocks is only a fraction compared to the production of red bricks and emits no pollutants and creates no toxic products or by products. It is produced by initially making a slurry of Cement + Fly Ash + Water, which is further mixed with the addi-tion of pre-formed stable foam in an ordinary concrete mixer under ambient conditions. Based on the trial mix-es, it is found that compressive strength of CLC blocks is more than the compressive strength of conventional clay bricks. The addition of foam to the concrete mixture cre-ates millions of tiny voids or cells in the material, hence the name Cellular Concrete.

MATERIALS AND ITS PROPERTIES

CEMENT AND ITS PROPERTIES:

Portland cement is the most common type of cement in general use around the world, used as a basic ingredi-ent of concrete, mortar, stucco, and most non-specialty grout. It was developed from other types of hydraulic lime in England in the mid-19th century and usually origi-nates from limestone. It is a fine powder produced by heating materials in a kiln to form what is called clinker, grinding the clinker, and adding small amounts of other

Abstract

Burnt Clay Brick is the predominant construction material in the country. The CO2 emissions in the brick manufacture process have been acknowledged as a significant factor to global warming. Now-a-days there are so many technologies involved in the recent development of concrete. Cellular Lightweight Concrete (CLC) is one of the recent emerging tech-nology in making concrete. The usage of Cellular Light-weight Concrete (CLC) gives a prospective solution to building construction industry along with environmental preservation. By using this type of concrete, we have found so many advantages when compared to the burnt clay bricks.

Cellular Light Weight Technology blocks can be used as an alternative to the red bricks, to reduce Environmental pol-lution and Global warming. It is produced by initially making slurry of Cement, Fly Ash and Water with different mix designs, which is further mixed with the addition of pre-formed stable foam in an ordinary concrete mixer under ambi-ent conditions. The addition of foam to the concrete mixture creates millions of tiny voids or cells in the material, hence the name Cellular Concrete.

The density is considerably reduced by using fly ash based cellular lightweight concrete than normal concrete and at the same time, the strength is not affected by appropriate design mix. When we use this type of concrete we achieve large volume by less amount of concrete. The manufacturing process of this type of concrete does not involve any high cost techniques. Manufacturing process of CLC is similar to normal concrete and in this additionally foam generating machine is used.

1401-1402

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International Journal of Research and Innovation (IJRI) materials. Several types of Portland cement are available with the most common being called ordinary Portland ce-ment (OPC) which is grey in color, but a white Portland cement is also available.

It is a fine mineral powder manufactured with very pre-cise processes. Mixed with water, this powder transforms into a paste that binds and hardens when submerged in water. Because the composition and fineness of the pow-der may vary, cement has different properties depending upon its makeup.

Cement is made by grinding together a mixture of lime-stone and clay, which is then heated at a temperature of 1,450°C. What results is a granular substance called "clinker," a combination of calcium, silicate, alumina and iron oxide.

Cement complying with any of the fol1owing Indian Standards may be used at the discretion of the manu-facturer:

• 43 Grade ordinary Portland cement,• 53 Grade ordinary Portland cement• Rapid hardening Portland cement• Sulphate resisting Portland cement• Portland pozzolana cement and• Portland slag cement.

Cement

PROPERTIES:

1. It possesses a high compressive strength.2. It is a corrosion resistance material and atmospheric agent has no appreciable effect on it.3. It hardens with age the process of hardening continues for a long time after the concrete has attained sufficient strength. It is this property of cement concrete which gives it a distinct place among building materials.4. It is more economical than steel.5. It binds rapidly with steel and as it is weak in ten-sion, the steel reinforcement is placed in cement concrete at suitable places to take up the tensile stresses. This is termed as the reinforced cement concrete or simply as R.C.C.6. Under the following two conditions, it has a tendency to shrink: a. There is initial shrinkage of cement concrete which is mainly due to the loss of water through forms, absorption by surfaces of forms etc. b. The shrinkage of cement concrete occurs as it hard-ens. This tendency of cement concrete can be minimized by proper curing of concrete.7. It has a tendency to be porous. This is due to the pres-ence of voids which are formed during and after its plac-ing. The two precautions necessary to avoid this tendency

are as follows: a. There should be proper grading and consolidating of the aggregates. b. The minimum water-cement ratio should be adopted.8. It forms a hard surface, capable of resisting abrasion.9. It should be remembered that apart from other materi-als, the concrete comes to the site in the form of raw ma-terials only. Its final strength and quality depend entirely on local conditions and persons handling it.

FLY ASH AND ITS PROPERTIES:

Fly ash, also known as "pulverized fuel ash" in the United Kingdom, is one of the residues generated by coal com-bustion, and is composed of the fine particles that are driven out of the boiler with the flue gases. Ash that falls in the bottom of the boiler is called bottom ash. Fly ash is generally captured by electrostatic precipitators or other particle filtration equipment before the flue gases reach the chimneys of coal-fired power plants, and together with bottom ash removed from the bottom of the boiler is known as coal ash. Depending upon the source and makeup of the coal being burned, the components of fly ash vary considerably, but all fly ash includes substantial amounts of silicon dioxide (SiO2) (both amorphous and crystalline), aluminum oxide (Al2O3) and calcium oxide (CaO), the main mineral compounds in coal-bearing rock strata.

Constituents depend upon the specific coal bed makeup, but may include one or more of the following elements or substances found in trace concentrations (up to hun-dreds ppm):arsenic, beryllium, boron, cadmium, chro-mium, hexavalent chromium, cobalt, lead,manganese, mercury, molybdenum, selenium, strontium, thallium, and vanadium, along with very small concentrations of dioxins and PAH compounds.

In the past, fly ash was generally released into the atmos-phere, but air pollution control standards now require that it be captured prior to release by fitting pollution control equipment. In the US, fly ash is generally stored at coal power plants or placed in landfills. About 43% is recycled often used as a pozzolan to produce hydraulic cement or hydraulic plaster or a partial replacement for Portland cement in concrete production. Pozzolan ensure the setting of concrete and plaster and provide concrete with more protection from wet conditions and chemical attack.

Fly Ash

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International Journal of Research and Innovation (IJRI)

Magnified View of Clc Block

PROPERTIES:

The physical and chemical properties of Fly Ash arePhysical Properties Specific Gravity 2.54 to 2.65 gm/cc Bulk Density 1.12 gm/cc Fineness 350 to 450 M2/Kg

Chemical Properties

Silica 35-59 % Alumina 23-33% Calcium Oxide 10-16% Loss on ignition 1-2% Sulphur 0.5- 1.5% Iron 0.5- 2.0 %

Picture of foam

Bad effect of rcc slab

EXPERIMENTAL INVESTIGATION

Process of casting clc blocks mix

The concrete mix design indicating the proportions of various ingredients should be worked out carefully keep-ing in view the desired physical properties of the finished blocks.Requirements of concrete mix designThe requirements which form the basis of selection and proportioning of mix ingredients are:• The minimum compressive strength required from structural consideration.• The adequate workability necessary for full compaction with the compacting equipment available.• Maximum water-cement ratio and/or maximum cement content to give adequate durability for the particular site conditions.• Maximum cement content to avoid shrinkage cracking due to temperature cycle in mass concrete.

Following are the four mix proportions considered:

MIX PROPORTION 1

MATERIAL QUANTITY PERCENTAGE OF MATERIAL (%)

CEMENT 316 KG 30.1

FLY ASH 422 KG 41.6

WATER 243 L 24

FOAM 1.1 L3.26

FOAM WATER 32 L

MIX PROPORTION 2

MATERIAL QUANTITY PERCENTAGE OF MATERIAL (%)

CEMENT 269 KG 31.13

FLY ASH 358 KG 41.43

WATER 206 L 23.84

FOAM 1.0 L3.58

FOAM WATER 30 L

MIX PROPORTION 3

MATERIAL QUANTITY PERCENTAGE OF MATERIAL (%)

CEMENT 225 KG 23.7

FLY ASH 458 KG 48.24

WATER 223 L 23.48

FOAM 1.4 L4.57

FOAM WATER 42 L

MIX PROPORTION 4

MATERIAL QUANTITY PERCENTAGE OF MATERIAL (%)

CEMENT 269 KG 31.42

FLY ASH 358 KG 41.82

WATER 195 L 22.78

FOAM 1.2 L4

FOAM WATER 33 L

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International Journal of Research and Innovation (IJRI) For every mix proportion 3 specimens of size 0.15X0.15X0.15 m cube moulds are casted and done steam curing and conducted the following tests:• Density Test • Compressive strength test.

DRY DENSITY TEST:

Objective:- To determine the density of hardened lightweight con-crete sample.

Apparatus:- Weighing scale- Three cube samples of size 0.15x0.15x0.15 m

General Note:- For more economic sample are to be taken from com-pression test sample before doing the test- Three sample are going to be used and average result will be taken

Procedures:1. Weight sample using weighing machines.2. Get the average weight of those 3 samples.3. Calculate the density using the formula given below

weighing machine

INDIVIDUAL WEIGHTS OF THE SAMPLES

MIX PRO-PORTION

SPECI-MEN 1 WEIGHT (KG)

SPECI-MEN 1 WEIGHT (KG)

SPECI-MEN 1 WEIGHT (KG)

AVERAGE WEIGHT (KG)

1 3.2 3.3 3.3 3.26

2 3 2.95 3.1 3.01

3 2.65 2.73 2.7 2.69

4 2.8 2.9 2.86 2.85

The Dry Densities of the blocks for the respective mix proportions:Mix proportion 1

Mix proportion 2

Mix proportion 3

Mix proportion 4

Mix Proprtion 4

SPECIMEN 1Size of the cube =150mm x 150mm x 150mmArea of the specimen (calculated from the mean size of the specimen) =22500mm2

Expected maximum load =fck x area44800= fck X 22500fck= 48375/22500fck= 2.15 N/mm2

Specimen 2

Size of the cube =150mm x 150mm x 150mmArea of the specimen (calculated from the mean size of the specimen) =22500mm2

Expected maximum load =fck x area45200= fck X 22500fck= 42750/22500fck= 1.9 N/mm2

Specimen 3

Size of the cube =150mm x 150mm x 150mmArea of the specimen (calculated from the mean size of the specimen) =22500mm2

Expected maximum load =fck x area45200= fck X 22500fck= 47250/22500fck= 2.1 N/mm2

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International Journal of Research and Innovation (IJRI) Average Compressive strengths of Blocks are:Compressive strength values

MIX PROPO-RTION

SPECIMEN 1 fck (N/mm2)

SPECIMEN 2fck (N/mm2)

SPECIMEN 3 fck (N/mm2)

COM-PRESSIVE STRENGTH VALUE (N/mm2)

GRADE

1 3.16 3.0 3.2 3.12 3.5

2 2.75 2.81 2.79 2.78 3.5

3 1.99 2 2 2 2.5

4 2.15 1.9 2.1 2.05 2.5

RESULTS:

The considered four mix proportions are casted, done curing and tested against the mix proportions. The Dry Densities and Compressive strengths of the blocks are listed in the below table:

Density results.

MIX PROPRTION DRY DENSITY (KG/m3)

PROPORTION 1 1000

PROPORTION 2 900

PROPORTION 3 800

PROPORTION 4 850

The below graphs shows the DENSITIES of mix propor-tions:

Compressive strength results

MIX PROPRTION COMPRESSIVE STRENGTH (N/mm2)

PROPORTION 1 3.12

PROPORTION 2 2.78

PROPORTION 3 2

PROPORTION 4 2.05

CONCLUSION:

The initial findings have shown that the lightweight con-crete has a desirable strength to be an alternative con-struction material for the industrialized building system.

The strength of aerated lightweight concrete blocks are low for lower density mixture. This resulted in the incre-ment of voids throughout the sample caused by the foam. Thus the decrease in the compressive strength of the con-crete.

The foamed lightweight concrete is not suitable to be used as non-load bearing wall as the compressive strength is 27% less than recommended. Nevertheless the Compres-sive strength is accepted to be produced as non-load bearing structure.

As Cellular light weight Concrete Blocks are less in weights and Densities they can be called as light weight blocks. Using these blocks can reduce the wall load on the slabs, which in turn reduces the reinforcement in the slabs and beams of the structure.

Generally we use can also customize the brick size in CLC technology which can reduce the work time and wall will be finished in short time. Construction of walls can also be done by using wall panels same as the way of doing shuttering work for the slab.

SCOPE OF FUTURE WORK:

In the future the usage of cellular light weight blocks will be vast as it has many advantages compared to regular bricks using in the present market and these bricks are eco-friendly.

By using the cellular light weight concrete wall can be constructed by using panels instead of casting blocks with different mix proportions which is suitable for the work. Mix proportions for the blocks and panels work may vary mainly in water cement ratio.

Using the different mix proportions by changing the ce-ment and fly ash percentages we can make the blocks which can be used for the works like compound walls, parapet walls etc. Flooring base course can be prepared by the Cellular light weight concrete.

Tests like Nail test, water absorption test, thermal con-ductivity tests can also be done for the blocks if neces-sary.

In the future usage of Cellular light weight concrete will increase and many other products can be arrived and there is scope for constructing a simple non load bearing structure like an independent house can be done only by Cellular light weight concrete.

BIBLIOGRAPHY IS CODES:

• IS 2185 (PART 4): 2008 CONCRETE MASONRY UNITS – SPECIFICATION PART 4 PREFORMED FOAM CELLULAR CONCRETE BLOCKS.

• IS 1077 – 1992; Common burnt clay building bricks – specification (fifth revision).

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International Journal of Research and Innovation (IJRI) • IS 1805 – 1987; Structural use of unreinforced masonry (third revision)

• IS 2185 (Part 1&3): 2005; concrete masonry units – specification, part 1 for hollow and solid concrete blocks and Autoclaved cellular (aerated) concrete blocks.

• “National Building Code of India 1983”Bureau of Indian Standards, New Delhi.

Author

G.Deepa,Research Scholar,Department of Civil Engineering,Aurora's Scientific Technological and Research Academy, Bandlaguda,Hyderbad, India.

Mythili Rao, Assistant Professor, Department of Civil Engineering, Aurora's Scientific Technological and Research Academy, Hyderabad India.

Venkata Ratnam, Associate professor,Department of Civil Engineering, Aurora's Scientific Technological and Research Academy, Hyderabad India.