Introduction

Concrete is the most important element for construction industry. The

reason concrete made is to give any shape to build man made environment.

The chemical properties of concrete are water, cement, gravel, sand and air.

The basic procedure to make customary concrete is mixing sand, cement,

gravel (gravel is made by putting larger rock into rock crusher that crushes the

rock to specific sizes) and accede to dry with air, this progression called

cement hydration procedure. If we turn back to history, concrete has been

using since 12,000,000 BC. Concrete is basically man made stone, that can

shaped in any form to construct environment. Concrete is indeed the most

used man-made material in the world, nearly three tons used once a year for

each man, woman and child. Twice as much concrete is used around the

world than the total of all other building materials, as well as wood, steel,

plastic and aluminum. None of these further resources can substitute concrete

in terms of effectiveness, price and performance for most purposes. Though

all properties of concrete coming from nature, but still it has some impact on

environment when it is exposed to environment. That environmental exposure

condition might be mild, moderate, severe, very-severe or extreme level.

Types of concrete

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There are a lot of different kinds of concrete, below mentioned are some of

the few major concrete types that are widely used in construction industry.

1. Dry Ready Mix

This type usually comes in a bag containing all necessary components in it

except for water. It is usually used in Home Improvement stores and repairs.

If you follow the manufacturer’s instructions, this type of concrete is nearly

foolproof meaning it is most suitable for indoor repairs and improvements.

This mix has proven to be the most expensive compared to others even

though for small projects, ready mix can be more cost effective.

2. Ready Mix

This type of concrete is harder to find compared to dry ready mix. As the

name suggest it is ready to use meaning it already has water added to it.

Mostly kept in a trailer with a rotating drum that mixes the concrete as you go.

This type of concrete is much more expensive compared to the one above as

it may cost you other small expenses such as transportatio0n costs etc.

Even though it may sound convenient, it can have its disadvantages such as

you must buy a car, which can mix this, concrete and transport it.

Above are sample pictures of Dry Ready mix concrete from different

manufacturing companies.

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3. Bulk Dry Materials

This type of concrete is the best option for large projects. It involves you

buying your own bulk material and mixing it yourself. You can manage the

strength of the concrete. Bare in mind there is a cost of delivery of the bulk

material.

4. Transit Mix

Highly used by contractors. It comes premixed and ready to use. It is time

saving as you can do one large pour at once.

Properties Of Concrete

When water and cement are mixed together, a chemic process of hydration

takes place and the concrete takes about 2hours to change from plastic to

solid.

As curing continues, concrete continues to strengthen, as most of its strength

has been proven practically to come from the curing environment.

In the first 10 days, the concrete shouldn’t be allowed to dry-out. As the

chemical reaction takes place, heat is given off, sometimes known as ‘’Heat of

Hydration”

Uses of concrete

We can separate concrete by its usage. There are few categories we can

define based on concrete use, such as: Cast-in-place concretes, decorative

purpose, making fiber cement, making green roof, building design, white

topping.

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For heavy construction, concrete also very popular. For instance bridge,

culvert, high-rising building etc.

Different uses we can find:

Getting the strong structure.

Concrete has sound blocking ability

Resists insects

Resists disaster

Various kind of concrete made shape used for decorative purpose.

Concrete used for heavy construction, like we can see in the picture.

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This is house in USA showing that during the Tornado

How it sustain.

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Environmental Impacts of concrete

Concrete is made with four basic components, those are water, cement,

gravel, sand. All the components we can find from nature without effecting

environment less, but the making of cement do bring some harm to the

environment; let’s look at what are those impacts:

Need huge amount of natural energy

Kilning process of cement actually need lots of natural energy, that is basically

bad for our environment. A single cement kiln can burn more than a million

tires (vehicle tire) a year. Yet we need coals to produce faster and better

quality of cement.

Remedy: The waste fuel, used motors oil, cleansing solution, scrap tires can

be used to save the energy.

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CO2 Discharge:

During the making of cement, there are two different kinds of carbon dioxide

(CO2) emissions. One is burning fossil fuel to operate the kiln. Approximately

3/4 ton of CO2 discharges per ton of cement. The chemical process of

limestone into lime in the cement kiln also produces CO2 with the chemical

formula, (CaCO3 + heat = CaO + CO2). Combining these two sources, for

every ton of cement produced, 1.25 tons of CO2 is released into the

atmosphere where CO2 will bring harm to the Ozone layer.

Remedy: To reduce the CO2, we can use agriculture waste, natural gas,

beside that we can use waste limestone to react less to produce CO2.

Other Air Emission:

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Beside CO2, throughout the making process of concrete it generates

considerable quantities of air-pollutant. It produces lots of dust majority of

which results from the cement production handling raw materials, grinding

cement clinker, and packaging list goes on. This dust is hazardous for human

health.

Remedy: This part actually very hard to get rid of, but some measure can be

taken, like those labors are working at site, the can wear mask, so that those

dust can’t get in to their lungs.

Water Pollution:

For washing gravel to reuse or first time have to use pond water, otherwise

river. This washing method also include equipment cleaning is often

discharged into setting ponds or rivers where the solids can settle out. Those

solid most of the time will remain inside the water and capable to damage the

eco-system underwater.

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Remedy: Source pond can be man-made, so that without interrupting the

eco-system, the cleaning procedure can be accomplished.

Solid Waste:

We can’t just overlook the solid waste of concrete after any construction.

There will always have solid waste remain, when construction is done and if

the solid is not remove from the site of the construction, then it might cause

damage to the eco-system by the surrounded area. Most of the time concrete

is responsible for the solid waste.

Remedy: Recycle process is the best solution to dispose of solid materials.

As soon as construction finishes, we can recycle them and clean the site.

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