Geopolymer cement: Foundation for eco-friendly building industry.
Cement manufacturers are amongst the highest polluters in the world. They are responsible for producing more emission per capita than aviation. With an increasing demand of buildings and other concrete works, how can they ensure the cement they use isn’t wrecking our planet?
Bricks are one of the most used materials for construction. With the rising demand of building materials and increased construction, the development of new building materials has risen. But, the traditional ways of brick production causes severe damage to the environment and human health. However, with the rise in population and their awareness on health issues, a clear need of searching and replacing the existing techniques came up which were to be more efficient and durable alternatives. This search, production and use of alternative materials led to the invention of geopolymers.
The weakest link between two tiles is where they meet: the tile joint, which is sensitive to acids and fungal growth. BASF researchers have therefore developed a joint grout, PCI Geofug®, which is robust and virtually cleans itself. The new mortar contains geopolymers, which are based mainly on aluminosilicates (see picture). These are inorganic materials that are chemically related to natural minerals. As a result, they are practically as hard and as durable as stone. Once the grout is applied, the geopolymers form a three-dimensional network that has a ceramic-like surface once hardened. Even acidic household cleaners barely harm the joints. The surface is strongly hydrophilic, which means that cleaning water spreads out over the joint and removes any existing dirt, which can then be easily rinsed away.
Geopolymer cement concrete is eco-friendly because it is made from the utilization of waste material such as fly ash and ground granulated blast furnace slag (GGBS). Fly ash is the waste product generated from thermal power plants and ground granulate blast furnace slag is generated as waste material in steel plants. Both these elements are then processed by appropriate technology and used for concrete works in the form of geopolymer concrete.
The main source of silicon and aluminium for geopolymers is by the thermally activated natural materials or industrial by-products and an alkaline activating solution which helps polymerize these materials into a binder. Hence, Geopolymer cement is also known as activated cement or inorganic polymer cement.
So to summarize, the following materials are required to produce this concrete:
- Fly ash
- Fine and coarse aggregates as required for normal concrete, and
- Alkaline activator solution for GPCC as mentioned above
Geopolymer cement is known to have a compressive strength of upto 70 MPa (N/mm2) as one of its properties. This concrete gains its strength more rapidly and faster than ordinary Portland cement concrete. Apart from this, geopolymers has more qualities than one: the drying shrinkage is much less as compared to cement concrete which makes it better suited for thick and heavy structures, it has low heat of hydration in comparison, its fire resistance is considerably better, the concrete’s jas chloride permeability rating of ‘low’ to ‘very low’ and it lastly, it possesses the quality of being highly resistant to acids.
All the information above might make you wonder about its applications since there are such differences between the two concretes i.e. Portland concrete and Geopolymer. Well surprisingly, the application is the same. However, this material has not been popularly used for various applications. It has been more used for construction of pavements, retaining walls, water tanks, precast bridge decks.
So, does this concrete fulfill its purpose of giving rise to an eco-friendly building industry? It does. Recently world’s first Structural Building, The University of Queensland’s Global Change Institute (GCI) has been constructed with the use of geopolymer concrete. It is a four storey high building for public use. It stands firm and steady which shows that the innovation works. Geopolymer cement has proved itself to be more effective and efficient. It has the power to change the future of the construction industry and the environment, for the better.
Image Credit: Hassel Architect
According to the latest research report, the Global Geopolymer Market has been estimated at USD 1,502.6 million in 2015 and is projected to reach USD 7,184.32 million by 2020, at a CAGR of 36.74% during the forecast period from 2016 to 2020. The market is expected to be driven by construction chemicals as well as pre-set products oriented industries such as bricks and slabs, sealants & grouts, and others. The customer base is across markets from buildings, pavements, embankments, tunnel linings, railway sleepers to repair and rehabilitation of pipes, flooring and wall cracks as well as fireproofing panels.
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