GREEN CEMENT - TYPES, APPLICATION AND ADVANTAGES

Green Cement

Green cement is a form of cement produced with the help of a carbon-negative manufacturing process.This cement is environmentally friendly product that minimizes carbon footprint of cement production.The concept of green cement emerged with the discovery of geopolymer cement in 1950s.Geopolymer cement is manufactured by using aluminosilicates instead of calcium oxide which damaging the environmental badely. The silicates can be obtained from industrial waste materials such as fly ash and blast furnace slag.

Green cement manufacturing reduces the cement intake.This cement reduces the carbon footprint upto 40%. Apart from reducing carbon dioxide emissions, the green cement manufacturing process also helps to maintain cement strength.It is composed of calcined clay and powdered limestone,it has desired characteristics such as reduced porosity and enhanced mechanical strength.

Benefits of Green Cement

1. Make Use of Industrial Waste

Fly ash a by-product of thermal power plant is produced in a large quantity which requires large area to disposed it.Green cement not only makes use of the fly ash waste but also protects the land from harmful environmental effects.

2. Requires Less Energy

The materials used in the traditional cement manufacturing process requires large amount of natural gas/coal for heating purposes.In green cement manufacturing industrial by-products are used as raw material which requires less energy. Green cement is more resistant to changes in temperature, therefore reducing the costs associated with both heating and cooling.

3. Lower Carbon Dioxide Emission

Clay, sand and pulverized limestone are some of the ingredients used in traditional cement.These ingredients requires heat releasing approx 5% to 8% of the total carbon dioxide.Green cement on the other hand does not requires as much heat during its production releasing upto 80% less carbon dioxide.

4. Long Lasting

Green concrete has a lower shrinkage rate and also becomes stronger far more quickly than concrete made with traditional cement.And since green concrete can withstand temperature as high as 2400℉, it makes building significantly more fire resistant.

Types of Green Cement

1. Ekkomaxx Cement

It is a type of green cement produced by Ceratech company in the USA.It is composed of 95% fly ash and 5% of renewable liquid additives.

The main characteristics of Ekkomaxx cement are high early strength, resilience, crack resistance, low chloride permeability, sulphate attack resistance, durability, corrosion resistance which is more than three times of conventional cement and the resistance to freezing and thawing is greater than that of normal cement.

2. Geopolymer Cement

Geopolymer, cement is a binding system that hardens at room temperature.It is also known as alkali-activated cement,is produced from aluminosilicates instead of the more environmentally damaging calcium oxide.The aluminosilicates are obtained from industrial by-product like fly ash.

3. Magnesium Oxychloride Cement

Magnesium oxychloride cement is also known as Solar cement.It is an environment friendly and carbon neutral cement.It is produced from magnesium oxide powder and concentrated solution of magnesium chloride.

The magnesium oxychloride cement has high compressive strength and set quickly and magnesium oxide absorb carbon dioxide from the atmosphere, but water can reduce its strength.However this weakness of MOC can be tackled to certain extent by introducing 15% of fly ash and the same amount of silica fume.The additives fill the pore structure in MOC which makes the concrete denser.Both strength and durability of concrete is improved considerably.

4. Ferrocrete

The ferrocrete cement is manufactured by mixing silica and iron which are waste byproduct from steel and glass industry.This material mixture is then cured with CO2, and consequently, it potentially becomes carbon negative materials.

5. Calcium Sulfoaluminate Cement

The calcium sulfoaluminate cement is a specially used in many applications where high early strength and fast setting development are necessary such as bridge decks, airport runways, patching roadways, tunneling etc.The calcium sulfoaluminate cement is produced of a kiln that requires a temperature of 2250℉ rather than 2500℉ of conventional cement.The calcium sulfoaluminate cement sets rapidely gain 28day strength of conventional concrete in 24 hours.

6. Cement Produced Using Superheated Steam

The superheated steam cycle will be used to modify the cement particles and render them more sensitive.The CO2 generated may be detected through this phase after it has been extracted.

7. Cement Produced With Reactive Hydrothermal Liquid Phase Densification

This form of cement is manufactured using the same raw materials as Ordinary Portland cement but at lower temperatures and through specific chemical reactions which generate less CO2 compared to convention Portland cement production processes.

Advantages of Green Cement

• Reduces the emission of CO2 as it does not requires as much heat during production, releasing upto 80% less carbon dioxide.
• Make use of industrial waste such as fly ash, silica fume and last furnace that may require several acres of land to dispose it.
• Requires less energy.