Production of Brick and Blocks

8/14/2019 Production of Brick and Blocks

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SECTOR: CONSTRUCTIONOCCUPATION: masonry WORK

UNIT OF COMPETENCY: produce brick & blockMODULE TITLE: producing brick & block

INSTITUTION: ALAMATA TVET CENTER

(ALAMATA, TIGRAY, ETHIOPIA)


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Information sheet one Plan and prepare for workSafety

Objective After completing this learning element, the trainee should be able to list and explain

All safety precautions to prevent accidents give proper care for hand tools, equipments and should

also perceive those safety rules during the construction of formwork.

1.1 Personal safety, working clothes and shoes Personal safetyIt is dangerous to work with sharp edge tools and talk at the same time. Be agreeable

with your neighbor workman. Respect his right and privileges. Rememberingaccidents prevented today will help make a living tomorrow. Some safety procedures

should be followed at all times. Pay close attention to what is being done.

The primary important to protect the workman from accidents is to identify possible

hazards and take the necessary safety measures to eliminate the hazardous. Before

you go to work on any job, make sure your entire body is properly protected and

provided other personal protective equipment.

Safety helmets or hard hats should be wearing by workers in all construction sites

where they might be exposed to head injury from falling objects.


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SAFETY EQUIPMENT1. Helmet

Protects the carrier from down falling items. It should be a must for everybody whoworks or moves on a building site.

Helmet

2. Ear protection

Protects the carrier from damages of the ears.

3. Safety boots

Safety boots are equipped with three safety measures. It must have:

1. Toes protection hood

A steel hood to protect the toes from down falling heavy thing

2. A steel layer inside the soles protects the carrier from stepping to a turned up nail.

3. Benzene and oil resistant soles

Safety boots

Rubber boot: - Protects the workers feet from colds, chemical, and mud in the

working area.


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4. Safety goggles

Necessary during chiseling and grinding work, protects against chips parking

around from the work piece

Safety goggles

Goggle: - Protects eyes of the workers during welding of Metal works and

when placing reinforcement in the form of work. Goggles with safety glass or plas.

Goggle

5. Mask: - Protects eyes of the worker from other endangering object and dust during

construction.

Mask

6. Glove:-Protects the workers from oils, chemicals, and dust

And other dangerous material that affect the skin.


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formation sheet twoMix aggregates and cement

oncrete block masonry materials

Lightweight aggregates (crush). These consist of natural and artificial materials of

very low density so that the resulting concrete is also quit light in weight, generally

within a range of 350-750 kg/m3. These concrete types find special application, in

sound proofing and heat proofing construction. They are also used extensively inthough manufactures of light weight pre-cast concrete blocks.

rdinary Portland cementhis is far the most common cement used in general concrete construction

Cement (often called Portland cement) is a combination of lime stone [calcium

carbonate] and silica, which is found in some type of clay. Alumina, iron oxide and

Magnesia are presenting small quantities. The cement may also contain calcium sulphate

to extend the setting time.
http://en.wikipedia.org/wiki/File:10mm-aggregate.jpghttp://en.wikipedia.org/wiki/File:10mm-aggregate.jpg


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Water

Water fit for drinking is generally suitable for making concrete. Substances in water

that, if present in water that, if presenting large amounts, may be harmful are: salt, oil,

industrial wastes, alkalis, sulphates, Organic, Matter, silt sewage etc.

Water-used in concrete mixes has two functions .The first is to react chemically with

the cement which will finding set and harden, and the second function is to lubricate allother materials and make the concrete workable.

(I) MIXING block making materials Concrete can be mixed either manually by hand or mechanically by machine.

For hand mixing- a clean surface should be selected- Or a wooden water-tight plat form should be provided

- It is advisable to use 10% extra cement in addition to the specified

-Quantity to compensate for lower strength resulted by hand mixing.

By machine mixing- It is generally preferred & recommended- It gives a better & uniform mix than hand mixing

The mixing process:-

1. First, cement and crush should be mixed =mix1 3 times2. then mix1+ water =mix23 times = suitable consistency mix concrete The measured quantities of crush and cement should be turned over from one spot to

another, with shovels, a sufficient number of times to produce a mass of uniform

color. Preferably the cement and sand should be mixed first and then then; the twomaterials should then be mixed thoroughly until the crush are uniformly Once the

dry mix is completed, the measured amount of water is added slowly and turnedover with shovel until the mix is uniform and the desired workability and

smoothness is obtained.


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Batching and mixing concrete materialsAfter the type of concrete to be produced is decided and the mix quantities are

determined by calculation, all materials should be measured accurately.Batching by weight = using balance

Batching by volume =using measuring box of size 400x350x250mm = 0.035m3= 35lit

Fig1.4. Measuring boxExample a proportion of 1:3 by volume Mix

1 bag of cement = b/se 1 bag = 35 lit (no need of measuring) 3 box crush


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Tools & equipments used for brick & block producing

Tools used for brick & block producingSpade;-is used to mix small amount of mortar & concrete

Mortar barrel/ drum

This is used by mason, plasterer, tiller, etc, and serves to prepare small amount ofmortar right at the working place. It is also used as temporary mortar storage, supplied

from mixing station, and to control water ratio of the mix when it gets dry. Always,keep it workable and clean.

Bucket

A Bucket is used to serve small amount of water or material and to take the tools after work.

Brush

Is used for wetting the building stones, cleaning fresh mortar joints of masonry wall, to clean hand toolsbefore and after use and to clean dust on surfaces.

Timber platforms

Flat steel platforms

Trowel

Float

Block caster metal (steel

Equipments used for brick & block producingMIXER;- are used to mix more amount of mortar and to save the time

Wheelbarrowis used to services material and to take the tools after work.

Block and brick producing machine

Cast concrete into molds


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1 Information sheet three Cast of concrete into moulds2 block producing machine

It is used for large amount of concretes. It is the fastest and more accurately producer than the others. Most of the time these kinds of machines are fixed in one place. It casts more than two per one casting. It saves time and energy. They do not need more human labor. It is expensive on market.

3 block caster metal (steel): it is used for where block producing machine are not available and if the

amount of concrete is very small,

Another advantage of this block casting is very easy to transport from oneplace to another.

It is easy to buy on market. It needs more human labor. It kills time and energy.

What is finishing (filling block maker machine?)

. Finishing takes place in two stages:

1 initial and finishing

2 final finishing.

Initial finishing

Concrete is first spreading to the level of the formwork or block casting

machine, then bull floated and left to set. in some cases spreading leaves a

good enough finish,

Finishing concrete

Floating there may be two stages in floating: the bull float, which is part of

the initial float. The power or hand floats which is part of the final float.

Floating helps compact and level the surface and close minor cracks.


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Compacting concrete BLOCK The purpose of compacting is to fill the voids and air bubbles in the concrete

mass. There are two methods of compacting when we make production of

blocks.

1, hand compacting- hollow concrete blocks is needed compacting until the airbubbles fills & to give strength to the hollow blocks using float, trowel and other flat

ended tools.

2, mechanical compactingthis is done with machine when we use block producing

machine.

Transporting and placing after producing blocks

- timber platforms- flat steel platforms- manual transport bucket & wheel barrow

Hallow block masonry The blocks available in Ethiopia are made of coarse mortar and known as crash,cement blocks materials and these are popular in wall construction. These

blocks are larger in size than the conventional bricks. The common face

dimension in the Ethiopian context is 200mm height x 400mm long, while the

thickness 100mm /150mm / 200mm.

The blocks are available as solid blocks and blocks with cavities. The blockswithout any cavities are called as concrete solid blocks CSB and the blocks with

cavities are of two types one concrete cellular blockCCB and other concrete

hallow blocks CHB.

Fig 6.1 hollow concrete block (HCB)

The laying operations such as positioning of guide bricks, formation of corner lay,

and plumbing, leveling and gauging operations are similar to brick work.


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Tips for concrete block practice It is important that blocks are to be protected from moisture exposure (rain

water / water wetting).

Blocks to be stacked on planks, off the ground to allow air circulation and toavoid absorption of moisture from the ground by capillary action.

Storage piles are to be covered with water-tight covers. At the end of work, the top course of blocks to be covered with a watertight

polythene sheet, to avoid entry of rain water or water applied for curing in to

the hollows or cells.

While making masonry with concrete blocks, only the edges of blocks are tobe wetted to increase their adhesion to mortar when the blocks are being laid.

Complete body should never be damped, while lying. As the surfaces of the blocks are rough, there may be a possibility of danger to

the hands and fingers of the masons; and hence hands are to be protectedwith gloves.


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Manufacture of bricks

Dehydration1,which is generally completed be for a temperature 700oc is reached during the

dehydration period the water less in the bricks after draying some of the

chemical such as hydrated aluminum ,silicate are dehydratedOxidation

Which leads to the formation an inter connected made of the new

crustal (oxidation is completed at about 900oc

Sintering

Isthe end of the process of brick product the temperature is 1200oc is burn

Stagesof manufacturing bricksThere are four basic stages.

1. Clay preparationMining crushing/grinding tempering **tempering is mixing of clay with water to a given consistency.

Chemicals may be added. e.g. baco3+soluble clay insoluble clay

2. Moldingit can be done by brick making machine or by hand- The tempered clay is then fed into moulds and pressed for shaping.

- Bricks at this stage are called green-brick.

3. Drying- the mass after has been molded, should be stacked in open shed for a period of

7 days up to 6 weeks for final drying.- drying enables the bricks to be stacked higher in the kiln without the bricksbecoming distorted by the weight above.

- drying helps to increase the firing temperature rapidly without bloating. (It is

a condition when gas/vapor is trapped within the brick.)

4. Firing- Its objective is to cause localized melting (sintering) of clay.

- sintering increases strength & decreases the content of soluble salt in the

bricks.

Main stages of firing are 100 co.evaporation of free water 400oc..burning of carbonaceous matter

700 co..dehydration

900 co..oxidation

1200co.sintering of clay


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Raw materials- bricks are manufactured from clays- Clays are fine grained soils which have resulted from the decay rocks.- When clays are mixed with water to the required consistency, claysbecome plastic i.e. easy to mold and capable of retaining their shapes on drying.Clays generally consist of AL2 O3, SIO2, FE2O3, COO, GO, CO2, SO3, K2O, NOand H2O

It is preferable for a brick to have a composition of:-

- Clay_________________ ____20-40 %- sand --------------------____------ 30 50 %

- others (lime, silt) -------_------ 20 35 %Alumina

are fine-grained mineral w/h makes the major part of the clay becomes plastic.

Alumina stronger & harder materialWhen mixed with water - it becomes plastic

-it is capable of being molded into shapes

SilicaA coarse-grained mineral either in the form of pure sand/compound of silicates.

- Useful in reducing shrinkage.-its presence produces hardness

However, excess UN combined silica results in brittleness.

- silica fuses at high temperature resistant to heat

lime- It acts as a flux to reduce the fusion point of silica.- it act as binder to clay & silica particles strength- Excess lime may cause the bricks to melt & lose their shapes.(caco3 900oc coo + co2)

Iron oxideIt lowers the fusion point of clay & silica this

imports the color of one brick at burn depend up

on the amount of iron oxide

The color of the brick is very attractive

temperature of 1200oc


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Information sheet fourCure and stack bricks/blocks Curingis keeping the fresh block wet to ensure setting and hardening of cement. advantage of curing1) Improves quality of the block

2) Improves the strength of the block3) Improves the durability of the block

Duration of curing Block is period of 28 days should be specified.

Assess quality of blocksTest of HCB

Blocks can be tested into two methods

Field test- appearance test- hammers test

- Free fall test- Soundness test

Laboratory testCompressive strength this method is checked from 1000 blocks 6pcs only. This means

from 400 hob is tested only 1. The minimum compressive strength of hob is shown

below.

class average 6 block individual block

a 42n/mm2 38n/mm2, 38n/mm2, 37n/mm2,

48n/mm2, 52n/mm2, 39n/mm2,b 35n/mm2 32n/mm2, 36n/mm2, 37n/mm2,

48n/mm2, 52n/mm2, 39n/mm2,

c 20n/mm2 18n/mm2,27n/mm2, 20n/mm2,

16n/mm2, 22n/mm2, 26n/mm2,


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Storing of brick and blocks materials

- bricks and stones should be piled near where they are needed- they should be handle carefully to minimize breakage- they should be piled on edges and a layer crossing over the previous-

The piles should be stable.

Information sheet five Clean up

Work area is cleared and materials disposed of, reused or recycled inaccordance with relevant legislation, regulations and job

specifications.

Materials using again and again is known as reusing, recycling.whenwe finish the work you must need maintaining plant, tools and

equipment to performing good housekeeping

Plant, tools and equipment are cleaned, checked, maintained and stored inaccordance with manufacturers' recommendations and standard work

practices

Production of Brick and Blocks

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