4.
Waste materials used in green concrete:
The waste materials utilized in green concrete can be grouped into three categories namely
agricultural, industrial, and municipal wastes as depicted in Fig. 1. To utilize their pozzolanic
properties in green concrete, the waste materials are often activated through physical or chemical
means or their combination.
4.1 Vegetable waste in concrete:
The usage of bio-fibers as concrete reinforcement has once again come under the limelight thanks
to the increased interest in environmentally friendly building materials. The mechanical qualities
of bio-fiber reinforced concrete components can be comparable to those of conventional products,
with the added benefits of being made from renewable resources, being less expensive, and
providing new opportunities for recycling concrete. Additionally, life cycle analyses were
performed to illustrate various scenarios, considering the number of materials needed and the
energy requirements for processing, transportation, and disposal.
It was determined that the use of bio-fibers as concrete reinforcement can only result in a sizable
environmental save under specific circumstances. While aspects like transportation, disposal, or
the potential for recycling the investigated items did not have a major impact, these were notably
influenced by material amounts. In the developing world, where many bio-fibers naturally grow,
the replacement of traditional reinforcements can not only result in significant environmental
savings for the production of concrete but also carries with it a remarkable cost reduction potential,
opening up new opportunities for sustainable and affordable construction materials, employment
creation, and business.
Fig 4: Checking Strength of Vegetable Concrete
Materials:
1. Bamboo:
Based on the findings from experiments conducted in 1995, computer models were mostly used in
the current investigation. Two simply supported beams, one with steel rebar and the other with
bamboo slat reinforcement, served as the study's functional components (Steel Reinforced Beam -
SRB). The beams had equal sections that were 300 cm by 12 cm by 30 cm. For bamboo and steel,
the proportion of reinforcement to volume was 3.3% and 0.78%, respectively.
Fig 5: Compare Between Bamboo and Steel Reinforcement, IMPACT
The findings are provided in this part, starting with the environmental performance of the bamboo
reinforcements, and moving on to the performance of the entire set of concrete reinforced beams.
Although the two investigated beams were of the same size, they had different mechanical
characteristics. The two functional units could not be deemed equal in terms of the service they
could offer because the SRB displayed an almost linear behavior under load while the BRB
observed a nonlinear response under the same set of loads. It was thought of altering the steel
beam's physical characteristics to match the mechanical reaction of the BRB and SRB to compare
the two reinforced beams fairly.
Unfortunately, this strategy is impractical and outside the purview of the current study. It was
chosen to run computer simulations under a specified load to understand the implications of the
SRB's changing physical qualities on the overall environmental saving to give baseline data.
2. Waste vegetables:
Concrete is the most often utilized material in the world after water.
Approximately 8% of the world's carbon dioxide (CO2) emissions are
attributable to the production of cement, a crucial component of
concrete. In kilns heated to roughly 1,400°C, where fossil fuels are
commonly utilized as an energy source, it includes burning a lot of
minerals, shells, shale, and other components, resulting in CO2
emissions. So, root vegetables can be used in this type of construction.
Beet sugar extraction or waste from carrots used to produce baby food
could be mixed with cement to make it stronger. The effects of the
ultra-thin sheets generated from these veggies and added to the cement paste on the hydration of
cement as well as the subsequent mechanical properties using computer models.
Adding vegetable waste-derived sheets to cement could enhance cement hydration. The sheets
served as reservoirs, increasing the amount of cement that could be wetted by water and enhancing
the cement's ability to bind. In addition, some of these carrot nanosheets stay in the cement after
hydration is complete and strengthen its structure.
For instance, pressing down on a carrot generates electricity that could run a tiny LED light or
other electronics.
When a bridge is constructed, for instance, electricity may be produced as a result of vibrations or
movement caused by passing vehicles or by pedestrians. This electricity from the concrete power
LEDs or lamps. It might also supply power to air pollution monitors.
Concrete's ability to generate electricity could potentially reveal information about a building's
condition. For instance, if there are cracks, the voltage generated would alter. Therefore,
incorporating a monitoring system that records electrical output could help identify when
something is wrong and a structure needs to be evaluated, preventing catastrophic failure.
Using their vegetable cement, we hope to lower the quantity of cement required to construct a
structure by 10 kilograms for every cubic meter of concrete. Further optimization efforts will
help to further minimize the amount of cement required.
Perspective in Bangladesh
In recent years, the use of bamboo fiber in concrete has gained attention in
the construction industry due to its various benefits such as higher
strength, increased durability, and reduced environmental impact
compared to traditional concrete. In Bangladesh, where bamboo is readily
available and widely used in construction, this could be an innovative and
sustainable solution.
Here are some perspectives on using bamboo fiber in concrete in Bangladesh:
1. Environmental sustainability: Bamboo is a fast-growing and renewable resource
that can be harvested without causing long-term damage to the environment.
Using bamboo fiber in concrete can reduce the environmental impact of
construction and provide a more sustainable alternative to traditional concrete.
2. Increased strength and durability: Studies have shown that bamboo fiber can
increase the strength and durability of concrete. In Bangladesh, where
earthquakes and other natural disasters are common, using bamboo fiber in
concrete can help buildings withstand these events.
3. Local availability: Bamboo is widely available in Bangladesh and using it in
construction can help support local economies and reduce transportation costs.
4. Cost-effectiveness: Bamboo is generally cheaper than traditional construction
materials like steel and using it in concrete can provide a cost-effective solution
for construction projects.
However, there are also some challenges to consider when using bamboo fiber in
concrete. For example, the processing of bamboo fiber can be time-consuming and
require specialized equipment, and there may be issues with uniformity and consistency
in the resulting material.
Overall, the use of bamboo fiber in concrete has the potential to be an innovative and
sustainable solution for construction in Bangladesh, but more research and
development are needed to fully realize its benefits.
