**1. Introduction**

World over there is a huge demand on the natural resources to cater to the housing, commercial spaces and the infrastructure for the ever growing population. Once, it has been decided to build a new building or an infrastructure, a very significant commitment to consume natural resources is made. Designers and contractors may be able to help limit that consumption, but they cannot change the overall commitment [1, 2].

Geopolymer, which is a synthesized inorganic material, is now used as an alternate binder in a wide range of construction applications and products. Davidovits [3] proposed that an alkaline liquid could be used to react with the silicon (Si) and the aluminum (Al) in a source material of geological origin or in a by-product material such as fly ash to produce binders. As the chemical reaction that takes place in

this case is a polymerization process, he coined the term 'Geopolymer' to represent these binders.

There are two main constituents of geopolymers, namely the source materials and the alkaline liquids. The source materials for geopolymers should be rich in silicon (Si) and aluminum (Al). These could be natural minerals such as kaolinite and natural clays. By-product materials such as fly ash, ground granulated blast furnace slag (GGBS), silica fume, slag, rice-husk ash, and red mud can also be used as source materials. The alkaline liquids are from soluble alkali metals that are usually sodium or potassium based. The alkaline liquid used in geopolymerization is a combination of sodium hydroxide (NaOH) or potassium hydroxide (KOH) and sodium silicate or potassium silicate.

Geopolymers are used to manufacture construction products like, geopolymer bricks [4], tiles and concrete. In geopolymer bricks and in geopolymer concretes, geopolymers do not form C-S-H gel (calcium-silicate-hydrates) unlike the Ordinary Portland Cements (OPC), for matrix formation and strength in a geopolymer concrete, but it utilizes the polycondensation of silica and alumina and high alkali content.

Earth is the oldest building material used by man for millennia. All over the world there are thousands of earth buildings which are over 500 years old. All these structures are still in sound condition and are well occupied. Even if earth is an ancient building material [1], the earth building tradition has been kept blooming in many countries and the technology is constantly being adapted to the requirements of modern civilization. In terms of sustainability, un-stabilized earth outdoes any other building material, including timber, owing to its low carbon footprint, its durability and its unlimited recyclability. The advantages of earth buildings are as follows [1]:


The earth as a construction material has the following disadvantages:


**41**

*Geopolymer Bricks Using Iron Ore Tailings, Slag Sand, Ground Granular Blast Furnace Slag…*

Iron ore tailings (IOT) [6], are waste material obtained from the process of smelting of iron. The rapid growth in the surface mines led the production of Iron Ore tailings which remains as overburden. The safe disposal or utilization of such vast mineral wealth in the form of ultra- fine slime remains a major unsolved and challenging task. Use of iron ore tailing will help in finding a new construction material and also help in finding a proper solution for disposal of tailings. In order to reduce the adverse impact of indiscriminate mining of natural sand, iron ore tailings which is the waste products of mining industries is used as an alternative to

Geopolymer is a type of inorganic polymer that can be formed at room temperature by using industrial waste or by-products as source materials to form a solid binder that looks like and performs a similar function to Ordinary Portland Cement (OPC). Geopolymer binder can be used in applications to fully or partially replace OPC with environmental and technical benefits, including an 80–90% reduction in

Mud bricks are made by mixing earth with water [7], placing the mixture into molds and drying the bricks in the open air. Straw or other fibers that are strong in tension are often added to the bricks to help reduce cracking. Mud bricks are joined

To summarize, geopolymer, an inorganic polymer, made using sodium hydroxide and sodium silicate with the prescribed molarity, can be used as binder with industrial waste/reject materials rich in silicon (Si) and aluminum (Al), such as fly ash, ground granulated blast furnace slag (GGBS), silica fume, slag and rice-husk ash, to make geopolymers bricks and tiles which conform to the standards of commercially available burnt bricks, and are environmental friendly and can also be called as green bricks since they do not use fuel for firing and also

A good brick earth, which is available as a natural resource, usually consist of 50–60% of silica, 20–30% of alumina, 5% of lime and 5–6% of oxide of iron [7]. However, for non-fired green bricks which can be made by using industrial wastes, materials to be used includes iron ore tailings (IOT), slag sand, fly ash and ground granulated blast furnace slag (GGBS), which can replace good brick earth of similar constituents [4]. Geopolymer is synthesized by using fly ash, GGBS, sodium hydroxide (NaOH), sodium silicate (Na2SiO3) and water. These bricks can

Iron ore tailings (IOT) [6, 8] are the waste materials obtained during the process of separating the valuable fraction of iron from the iron ore. The different steps involved in this process are crushing, screening, grinding, washing, jigging,

be manufactured without firing, but using geopolymer as binder.

Sand is one such material which is highly used in the construction industry. Sand has by now become the most widely consumed natural resource on the planet after fresh water. Depletion of sand in the stream bed and along coastal areas leads to the deepening of rivers and estuaries, and enlargement of river mouths and coastal inlets. Therefore, the goal of sustainable construction is to use locally available

*DOI: http://dx.doi.org/10.5772/intechopen.81748*

resources without affecting the environment and its people.

the river sand in the manufacturing of concrete and bricks.

CO2 emissions and improved resistance to fire and aggressive chemicals.

with a mud mortar and can be used to build walls, vaults and domes.

do not contribute to the greenhouse gases.

**2. Materials and methods**

**2.1 Materials**

*2.1.1 Iron ore tailings*

c.Low resistance to abrasion requiring frequent repairs and maintenance.

#### *Geopolymer Bricks Using Iron Ore Tailings, Slag Sand, Ground Granular Blast Furnace Slag… DOI: http://dx.doi.org/10.5772/intechopen.81748*

Sand is one such material which is highly used in the construction industry. Sand has by now become the most widely consumed natural resource on the planet after fresh water. Depletion of sand in the stream bed and along coastal areas leads to the deepening of rivers and estuaries, and enlargement of river mouths and coastal inlets. Therefore, the goal of sustainable construction is to use locally available resources without affecting the environment and its people.

Iron ore tailings (IOT) [6], are waste material obtained from the process of smelting of iron. The rapid growth in the surface mines led the production of Iron Ore tailings which remains as overburden. The safe disposal or utilization of such vast mineral wealth in the form of ultra- fine slime remains a major unsolved and challenging task. Use of iron ore tailing will help in finding a new construction material and also help in finding a proper solution for disposal of tailings. In order to reduce the adverse impact of indiscriminate mining of natural sand, iron ore tailings which is the waste products of mining industries is used as an alternative to the river sand in the manufacturing of concrete and bricks.

Geopolymer is a type of inorganic polymer that can be formed at room temperature by using industrial waste or by-products as source materials to form a solid binder that looks like and performs a similar function to Ordinary Portland Cement (OPC). Geopolymer binder can be used in applications to fully or partially replace OPC with environmental and technical benefits, including an 80–90% reduction in CO2 emissions and improved resistance to fire and aggressive chemicals.

Mud bricks are made by mixing earth with water [7], placing the mixture into molds and drying the bricks in the open air. Straw or other fibers that are strong in tension are often added to the bricks to help reduce cracking. Mud bricks are joined with a mud mortar and can be used to build walls, vaults and domes.

To summarize, geopolymer, an inorganic polymer, made using sodium hydroxide and sodium silicate with the prescribed molarity, can be used as binder with industrial waste/reject materials rich in silicon (Si) and aluminum (Al), such as fly ash, ground granulated blast furnace slag (GGBS), silica fume, slag and rice-husk ash, to make geopolymers bricks and tiles which conform to the standards of commercially available burnt bricks, and are environmental friendly and can also be called as green bricks since they do not use fuel for firing and also do not contribute to the greenhouse gases.
