What is green concrete?
What is green concrete?
Since nature-lovers are concerned about environmental issues, the tendency to enter concepts such as “Green buildings” is increasing day by day. This technology aims to provide greater stability. Modern construction practices are orienting toward using green concrete and other novel building materials to create environmentally friendly urban structures.
Simply put, green concrete is produced from concrete waste and is environmentally friendly. Does it mean that conventional concrete is not compatible with the environment? For making conventional concrete, we need cement and new aggregates. It influences the environment in addition to increasing demands for concrete. Green concrete is made by using environmentally friendly materials instead of cement and aggregate. For more information about this concrete, please follow us.
Green concrete definition
A green or eco concrete structure is stable and has a long life cycle that requires little maintenance. Developed in Denmark in 1998, this concrete revolutionized the concrete industry.
Green concrete has nothing to do with the green color. The term “green” means this concrete is environmentally friendly. Eco concrete is very similar to conventional concrete. Yet, creating it is energy-efficient and environmentally friendly. The main goal of green concrete is to reduce the environmental impacts of concrete.
This concrete is produced from waste such as slag, power station wastes, recycled concrete, mineral wastes, glass wastes, incinerator residual, burnt soil, sawdust, combustion ash, etc. With green concrete, all phases of a concrete building are considered, including design, features, construction, and maintenance.
The below table shows the primary combination of conventional concrete and its replacement with green concrete:
|Raw materials||Replacement for concrete materials|
|1||cement||Fly solid ash, sludge ash, recycled glass, silica fume|
|2||Coarse aggregates (gravel)||Wastes recycle, prepared wastes of the mixed concrete, glass wastes|
|3||Fine aggregates (sand)||Fine recycled aggregates, demolished brick wastes, mine dust, marble powder wastes|
The importance of green concrete and sustainable development
There is a widespread use of cement-based materials throughout the world. Green buildings are essential in today’s world due to the exciting process of urbanization. As its name indicates, green concrete uses wastes in different industries in various forms, such as rice husk ash, micro silica, and others.
Due to its high energy demand, the building industry generally has a significant impact on the environment. As countries become more aware of greenhouse effects and environmental damage, green concrete is becoming more popular.
Eco concrete reduces greenhouse gas emissions and saves energy. Waste materials are used to replace cement in this concrete, making it very cheap. As a result, each unit of cement is produced using less energy. In addition, green concrete has higher compressive strength and durability than conventional concrete.
Using industrial wastes to produce eco concrete, which has the ability of sustainable development, reduces natural resource and energy consumption as well as emissions of environmental pollution. The marble sludge powder can be used as filler and fill the empty contents of the concrete. Natural sand and gravel were not categorized correctly in many regions and had a large amount of sludge. On the other hand, the dust of the stone mine does not have any sludge or organic impurity and can reach a desirable delicacy based on needs. As a result, it increased the concrete strength.
The dust from the stone mine and marble sludge powder was used as 100% replacements for natural sand in concrete to study the durability of green concrete compared to conventional one. As the impact of greenhouse gas emissions on the environment has become increasingly apparent in recent years, many researchers are focusing on CO2 emissions as an index of the environment.
What are the environmental advantages of green concrete?
Regarding the current situation of the world, we need a healthy environment to live in. Nevertheless, living in naturalistic surroundings does not mean we have to live like troglodytes. If we make decisions per the environment, we can move forward with both the environment and technology. Through the use of green concrete, we can normalize the relationship between humans and nature, maximizing the potential for both.
The advantages of this type of concrete are as below:
1- Reducing Carbon emissions
In the process of creating Portland cement, main materials such as limestone, sand, clay, and sand are heated up to 1450 C. The process is responsible for producing 5 to 8% of global CO2 emissions. By contrast, using green concrete can reduce CO2 emissions by about 80%. Using eco concrete will be a positive step if the government is focused on protecting the environment.
2- Reducing energy consumption
Portland cement is produced with a lot of coal or natural gases, but by mixing concrete with less cement and more fly ash, energy consumption can be reduced.
3-Using industrial wastes
Green concrete uses 25 to 100% fly ash instead of Portland cement mixture. Fly ash is a side product of coal combustion. The substance is collected from industrial plants (such as power plants) that burn coal as fuel. Thousands of hectares of ground are used for fly ash ejection. As green concrete usage increases, new methods for using fly ash are introduced.
4-Protecting water resources and natural habitat
As a result of the excavation of mineral substances for the production of cement and aggregates, the slope of the ground and vegetation are altered. This causes a change in ground drainage. Consequently, groundwater resources are adversely affected. Many cities and countries rely on groundwater as a natural water resource. Natural habitats and vegetation also undergo some changes.
What are the economic advantages of green concrete?
The construction industry is growing rapidly. The enormous development of construction increases demands for building materials. Aggregates are the main component of concrete. Due to the continuous extraction and availability of aggregates, many problems around providing materials and economics have emerged. To solve this problem, we need to find an alternative, and the solution for these problems is green concrete.
The economic benefits of eco concrete are as below:
In comparison to Portland cement, green concrete gains strength more quickly and needs less shrinkage. Therefore, its structural durability is greater than conventional concrete. Furthermore, eco concrete resists corrosion more effectively than conventional concrete.
Green concrete made from an industrial byproduct or by a simple method resists fire better at 1000 C than conventional concrete. It is crucial that the structure does not collapse during a fire emergency.
Minimum repair cost
A green concrete structure is durable and requires little maintenance and repair. As a result, construction costs are significantly reduced on a large scale due to the reduction in concrete rehabilitation costs.
Green concrete limitations
· Green concrete has the disadvantage of having a shorter life span than conventional concrete. As a result, dams and bridges cannot be built with these materials.
· The tensile strength of eco concrete is lower than conventional concrete. Therefore it needs more reinforcements (bars), which increase the construction cost.
· Water absorption is greater in green concrete compared to conventional concrete. So, structures made of green concrete need protection against water.
Green concrete use
Eco concrete uses are as below:
- Residual buildings
- Official buildings
- Commercial buildings
- Road Construction
- Urban massive construction (sculptures)
The use of concrete in construction is increasing, and we need new construction materials to maximize urban development. Thus, green or eco concrete is a viable alternative. The difference between green concrete and conventional concrete is that green concrete uses waste materials or materials that are environmentally friendly. By using waste materials instead of aggregates and cement, this concrete is inexpensive to produce. The use of eco concrete contributes to decreasing construction material demands and CO2 emissions while also reusing concrete waste.