Carbon reduction technology

1. Chapter 2; Literature review
Environmental impact of Cement Production
According to the Global Cement and Concrete Association (GCCA), around 8% of the world's
carbon dioxide emissions are attributed to cement production. As a key component of most
buildings, concrete is the second most used substance after water. The cement industry
produces 3.6bn tons of Ordinary Portland Cement annually, with a prediction of an increase to 5
billion metric tons by 2030. (add citation) Half of concrete carbon dioxide emissions are created
during the process of manufacturing clinker. Clinker is the key component of cement, it is used
as the binder in any cement production, it is produced by heating raw materials; limestone and
clay up to 1400°C-1500°C and then rapidly cooled forming the strong bond between the other
components in concrete. Furthermore, the extraction of these raw materials for concrete
production can have adverse effects on local ecosystems and biodiversity. quarrying limestone
involves using machinery to drill, blast, excavate, and crush raw materials. The process of cement
production and its use in concrete can have significant adverse effects on the environment
through carbon dioxide emissions during production to the environmental impact of quarrying raw
materials. The increasing in the production of the raw material for preparing cement generates
decrease in quantity of the non-renewable resources like limestone as such process of producing
such resources through natural environment have significant and long-term effects on the
greenery, which is the habitat of flora and funa that gets disturbed due to having exposure of
ecological imbalance (Mohamad et al., 2022). It shows that production of cement has long-term
impacts on the environment, which disturbs the ecological imbalance for centuries and has long-
term impacts on the living conditions for the living organisms. The continuous process of
decreasing of such natural resources, exposes the risk factors for the depletion for the coming
generation. Therefore, the phase of manufacturing of the raw material causes noise, dust and the
greenhouse gasses, which mainly contains the carbon dioxide that affects the environment and
increases the drastic and long-term effects of climate change (Mohamad et al., 2022). It
highlighted that there is immense need of using cement manufacturing those procedures that do
not impacts on the ecosystem and ultimately the climate change as already the effects of man-
made mistakes are tiring for the environment and have long-effects on the environment, which
are the cause of suffering due to adverse climatic changes, extinction of the animal species and
marine life along with several health impacts on masses. The industrial factories smokestacks
through cement and construction plants are the known contributors to produce poor quality of air
mainly in the urban developments (Devi et al., 2017). It represents the factories of cement
significantly contributing to creating the imbalance in the environment through disturbing its quality
of air as compared to villages. It has been highlighted also that other than carbon dioxide, there
are several other environmental emissions, which are nitrogen oxides (NOx), sulfur dioxide (SO2)
and gray dust (Devi et al., 2017). It represented that such emissions due to cement production
are drastic for the environmental conditions and have long-term impacts on the climate, change,
ecosystem and several other impacts on the life span of the living organisms. The effects of the
climatic change can impact on the temperatures of the environment, water resources decrease,

2. precipitation levels and its parameters, aquatic and terrestrial habitat, the species that have
become endangered and threatened, production of agriculture and several other natural and man-
made resources. Such environmental impacts are long-term and the result of man-made causes
and factors that are in practice for centuries and ignored due to societal and cultural gains and
survival of the fittest.
Materials Usage and Sustainable Practices in decreasing the negative impacts.
It highlighted that the World Business Council for Sustainable Development (WBCSD) and its
Cement Sustainability Initiative, which based on cement producers at the global level has
developed project on ‘Getting the Numbers Right’ for the first time as it provides an impressive
record for several global cement industries regarding the CO2 and energy performance (WBCSD,
2008). The manufacturing of cement is liable for 5 percent of global anthropogenic CO2 emissions
and 7 percent of industrial usage of power sources.
Such figures represented China's leading impact on the world’s cement industries. In 2018, the
United Kingdom released 7.3 million tons of carbon dioxide through cement and concrete.
Approximately 4.4 million tons out of total resulted through the ‘process emissions’ in the
manufacturing of clinker, 2.2 million tons through fuel combustion and remaining for electricity
usage and its transportation (MPA UK CONCRETE,2020) are represented in Figure 3.
Figure 4; Production of clink Studies shown in Figure 2, In 2020, China produced the most
cement worldwide, approximately 2.15 billion metric tons. India came in second, producing about
8.6% of China's output, while the United States rated as third, contributing 29% of China's
production. Such figures represented China's leading impact on the world’s cement industries. In
2018, the United Kingdom released 7.3 million tons of carbon dioxide through cement and
concrete. Approximately 4.4 million tons out of total resulted through the ‘process emissions’ in
the manufacturing of clinker, 2.2 million tons through fuel combustion and remaining for electricity
usage and its transportation (MPA UK CONCRETE,2020) are represented in Figure 3. The
infrastructure sector in the UK currently accounts for 16% of carbon emissions mainly and influences
an additional 37%, totaling 53%. By 2050, with other industries decarbonizing, this figure is projected
to increase by 90 percent. (UK Green Building Council, 2017).
Progress in mitigating carbon emissions from cement production worldwide

3. Reducing carbon emissions from cement production in developing countries is critical due to rapid
industrial growth. This requires adopting cleaner technologies, improving energy efficiency, using
alternative fuels and materials, and implementing supportive policies. Many techniques have been
studied to reduce cement production. Techniques such as Carbon Capture and Storage (CCS),
using alternative materials, fuel and energy efficient technologies have all been identified as
approaches to minimizing the emissions of Carbon. Nanotechnology presents another hope for
improvement, with researchers investigating ways to enhance the properties of cementitious
materials through nanoscale particles; where particles are 10 thousand times smaller than cement
particles are being used to improve the structure of hydrated paste in return improving
compressive, flexural strength, performance, and durability noticeable. However, these
techniques are not considered to be economical as it depends on proper dispersion, which
requires specific techniques that are cost intensive for construction industries to adopt at a
commercial scale. Other approaches such as using alternative binders, like Belite-ye eliminate-
ferrite cements are being studied as it requires less temperature than regular Portland cement
however the availability and cost of raw materials and technical limitations as well as the
requirement of more studies and validation limit their widespread implementation.
United Kingdom Roadmap to net zero.
Furthermore, the UK has implemented various approaches to enhance sustainability in
other areas of the construction sector:
- The production of the local concrete generates an average delivery distance to have
ready-mixed concrete of only 12 kilometers.
- It highlighted that 95 percent of concrete is generated locally in the United Kingdom.
- Concrete assists the economy of the country as approximately 90 percent of hard
construction and demolition is recycled as it highlighted that 100 percent is recyclable.
- The industry is considered as a net consumer of waste as it consumes more than 200
times of its waste and by-products through other industries than the waste that
accumulates at the landfills. (Leese, 2021)
These initiatives underscore the UK's commitment to sustainability and its leadership
role in driving environmental improvements within the construction sector. Thus, the
last century has experienced various promising initiatives originated through factories
to improve its sustainability to achieve a net-zero emission through 2050 (Adesina,
2020). It represents that sustainable development through achieving net-zero
emission is the need of the hour keeping in view the drastic impacts of CO2 on the
environment in the process of cement manufacturing. It needs to be highlighted that
2050 is considered to be risk-oriented phase of the environment keeping in view the
drastic impacts of cement manufacturing process, which pushed industries to look for
the several innovative procedures to ensure the assurance of achieving a net-zero

4. emission avoid experiencing a global warming temperature of 1.5 C and even above
as it’s the need of hour (Adesina, 2020). It represents that such initiatives are too late
but still should be focused to have a better future for the coming generations and to
decrease the impacts of man-made challenges that the present generations are
experiencing in a drastic manner.
China’s approach to minimize C02
Zhongwei first put forth the idea of "green high-performance concrete" in China in the 1990s,
emphasizing that this type of concrete is the way of the future for concrete development. China
encourages the use of alternative cementitious materials such as fly ash, slag, and silica fume as
partial replacements for OPC in concrete production. These materials have lower CO2 emissions
compared to OPC and can improve concrete performance. China has also invested research and
development to explore and develop low-carbon cement technologies. This includes the
development of blended cements with reduced clinker content. On contrary, according to the
latest facts word by Narayanan Neithalath, the Fulton Professor of Structural Materials in the
Schools of Sustainable Engineering and the Built Environment as stated, “If cement
manufacturing were ranked with individual countries based on their carbon impacts, the cement
industry would be the third largest CO2 emitted overall in the world after China and the United
States (Kullman, 2023). Such alarming facts of the year 2023 about China and the United States
of America are considered alarming that beside the high claims, presenting the globe with greener
concrete invitations is not a true reality as proclaimed. It heightened the need of working on the
real-based goals, initiatives and projections that assists in decreasing the carbon-dioxide
emission and greener concrete procedures in the manufacturing of the cement as it’s the
significant need of the hour and the impacts are alarming that could not be neglected.
Utilizing Waste By-Products as Alternative Binders in Construction Materials
In response to the environmental impact of Ordinary Portland Cement (OPC), various strategies
have emerged to reduce its usage and mitigate its associated carbon footprint. One significant
approach involves replacing traditional cement components with waste by-products, thereby
fostering sustainable practices while addressing waste management challenges. According to
recent statistics, incorporating waste materials like fly ash, slag, or rice husk ash into cement
production can significantly reduce carbon emissions and conserve natural resources.
(International Energy Agency, 2009). For instance, a study by the International Energy Agency
found that utilizing supplementary cementitious materials (SCMs) like fly ash or slag in cement
can reduce CO2 emissions by up to 15 percent. Moreover, the use of these waste by-products

5. can divert significant quantities of waste from landfills, contributing to circular economy principles.
It is highlighted that the construction materials like gravel, sand and rock; normally known as
aggregates are coarse-grained materials, which are extracted comparatively near to the factors.
Such materials are not often as a threat for the environmental policy or eco-innovation as such
compositions are significant for the economic process, due to having the leading components for
the whole chain of construction, housing sector, which includes structural and civil engineering,
manufacturing of cement, construction of road and railways, process of reconstruction and also
renovation (Bursi, 2009). Such massive mining volumes of the materials and environmental
intensity that comprises on land use conflicts, landscape reconstruction in the extraction phase,
sealing of soil and promotion in an unbroken net addition to have its pillage in the phase of
construction, consumption and emissions of energy in the process of extraction, process of
transportation and decreased extent resource depletion should not be neglected as phase of
process marks its significant importance in having cement for the construction purposes.
Fly ash: There are several waste examples, which could be incorporated for the replacement of
the clinker are noted as, slag, foundry sand, ash, spent catalysts and also the filter clay etc.
(Adesina, 2020). It's considered as the significant reason for such waste materials, which could
not be consumed to completely replace the limestone that is used to develop the clinker as a
result of its low content of calcium in comparison to limestone. Fly ash (FA) emerges as a
significant industrial byproduct resulting from the combustion of solid fuels. Comprising primarily
of unburned carbon (UC), metal oxides like silicon (Si), iron (Fe), calcium (Ca), and aluminum
(Al), along with various other inorganic substances, FA presents a powdery solid composition. Fly
ash specifically, serves as a cost-effective source of activated carbon, enhancing FA's adsorption
capacity. Studies have focused on applications in the construction sector, notably in cement and
concrete production. Incorporating FA into cement formulations, particularly in reduced nanoscale
dimensions, demonstrates improved durability and reduced pore size in concrete structures, as
well as being resilient to harsher environmental conditions. This utilization not only addresses
waste management challenges but also contributes to the development of more sustainable
construction practices. Professor Davis from the University of California conducted extensive
studies on fly ash blending, successfully implementing it in the Obama Project in the United
States. Additionally, the Canadian Department of Energy and Mineral Resources has produced a
substantial amount of fly ash for usage in cement, achieving substitution rates of over 50% while
maintaining durability and mechanical properties that meet application standards. India ranks as
the third-largest coal producer globally, with coal-based thermal power plants contributing around
70% of the country's total power generation capacity. However, the disposal of coal fly ash, often
stored in waste heaps, poses a significant environmental threat due to its potential to contaminate
soil, water, and air with metal pollutants. Efficient waste management strategies are crucial to
mitigate these environmental risks. With an annual generation of around 112 million tons,
fly ash has proven suitability for various applications like admixtures in cement, concrete,
mortar, and lime pozzolana mixture for bricks and blocks. Currently, the cement and
concrete industry accounts for 50% of fly ash utilization, while other sectors utilize it for
low-lying area fill (17%), roads, embankments (15%), dyke raising (4%), brick

6. manufacturing (2%), and emerging areas like the paint industry and agriculture for safe
disposal.
Top of Form
Silica fume
Silica fume, also known as micro silica, is a byproduct of the production of silicon and ferrosilicon
alloys in the manufacturing industry. It is composed mainly of very fine spherical particles of
nanocrystalline silica, typically with a diameter less than 1 micron. Silica fume is highly reactive
and pozzolanic, meaning it reacts with calcium hydroxide in the presence of moisture to form
compounds that contribute to the strength and durability of concrete. FA is mainly produced to
reduce the heat of hydration. China leads as the world's primary producer of silicon and high-
silicon alloy, with its annual production escalating from 400,000 tons in 2001 to 5,500,000 tons in
2015, constituting 68 percent of the total global output. Brazil, Norway, the US, and France are
also noteworthy producers of silicon. (Association, 2011) Figure 7; Production of silicon globally.
However, The disposal of silica fume presents several challenges the Occupational Safety and
Health Administration (Anonymous, 1986), which not reported any kind of health risks, therefore
the American Conference of Governmental Industrial Hygienists (ACGIH, 1992) has categorized
SF as hazardous and inhalation , the SF could develop minor health risks. As a result, many
researchers have studied ways to dispose of Silica Fume. Disposal options include landfilling,
incorporation into concrete, stabilization, recycling, encapsulation, and chemical treatment. These
methods aim to minimize environmental impact and maximize reuse where possible.
Plausible Solutions
The globe has to focus on the realities and need to cater such methods, techniques and
strategies that are practical as it’s the significant need of the hour. Through analyzing the
solutions there are several challenges and scarce options to make available the high
temperatures, which are needed to develop the required chemical reactions for the
manufacturing process (Kullman, 2023). It represented that still today the cement
manufacturing is recognized as a hard-to-decarbonize process, which is practiced by
industries that need to be stressed and highlighted to work on such methods that reduces
the carbon dioxide emission and are from the renewable sources as its the significant need
of the hour. Stated by Narayana Neithalath, “Several research projects around the world
at multiple solutions to this vexing problem as there is no lever to reducing concrete’s

7. carbon emissions, but there is a general consensus that process changes in cement
manufacturing could have the highest impact, though that could be the hardest thing to
do.” (Kullman, 2023). It highlighted that such solutions are the need of hour to be practical
and research oriented to have a better tomorrow that ensures safe environment through
controlling the present impacts on climate change, pollution, global warming and several
drastic impacts on health of masses, extinction of the species of animals, birds and marine
life and above all long-term impacts that are faced by masses in their every aspect of life
as it includes several health concerns, pandemics, decrease in life-span and unending
catastrophic impacts in future.
Experimental studies done using fly ash and silica fume
- Explain the case study
- Explain how relevant it is whats the advantage and disadvantage
- Explain how and why I have chosen to do my lab in this why because of previous
studies suggestions.
Existing regulations on the usage of fly ash and silica fume in SCC British standard
NEW MATERIAL
It highlighted that in the year 1986, Okomora developed the thought of Self-compacting concrete
(SSC) to develop a long-lasting concrete structure and improve quality in the industry of
construction. As the high-performance concrete (HPC) is a sustainable and abrasion-resistant
concrete produced with low water-to-binder ratio (w/b) and also cured in equal terms (Mustapha
et al., 2021). It represented that such materials should be brought into consumption to have
reliable and sustainable sources of the concrete production that are environment friendly. It
stressed that the maximum compressive strength of 87.06 Mpa has been achieved through
Portland-fly-ash through blending of the silica fume of 40 percent PC, 50 percent FA, and 10
percent SF at 28 days in the period of curing age that is recorded as 5 percent (Mustapha et al.,
2021). The adequate ratio of the required materials is important for having such concrete at the
end product that is long-lasting, renewable and environment friendly.

8. BIBLIOGRAPHY
Adesina, A. (2020). Recent advances in the concrete industry to reduce its carbon dioxide
emissions. Environmental Challenges, 1, 100004.
https://doi.org/https://doi.org/10.1016/j.envc.2020.100004
Bursi, Ms. C. (2009). (issue brief). Eco-innovation - putting the EU on the path to a resource
and energy efficient economy (pp. 1–126). Retrieved 2024, from
https://www.europarl.europa.eu/document/activities/cont/201109/20110906ATT25985/201
10906ATT25985EN.pdf.
Devi, K. S., Lakshmi, V. V., & Alakanandana, A. (2017). IMPACTS OF CEMENT INDUSTRY
ON ENVIRONMENT – AN OVERVIEW. ASIA PACIFIC JOURNAL OF RESEARCH,
1(LVII), 156–161. https://www.researchgate.net/profile/Kuruva-
Devi/publication/323029097_Impacts_of_Cement_Industry_on_Environment_-
_An_Overview/links/5a7d72cd458515dea40f98f5/Impacts-of-Cement-Industry-on-
Environment-An-Overview.pdf
Kullman, J. (2023, October 17). Curbing concrete’s carbon emissions with innovations in
cement manufacturing. Curbing concrete’s carbon emissions with innovations in cement

9. manufacturing | ASU News. https://news.asu.edu/20231017-curbing-concretes-carbon-
emissions-innovations-cement-manufacturing
Mohamad, N., Muthusamy, K., Embong, R., Kusbiantoro, A., & Hashim, M. H. (2022).
Environmental impact of cement production and solutions: A Review. Materials Today:
Proceedings, 48, 741–746. https://doi.org/https://doi.org/10.1016/j.matpr.2021.02.212
Mustapha, F.A., Sulaiman, A., Mohamed, R.N. and Umara, S.A. (2021). The effect of fly
ash and silica fume on self-compacting high-performance concrete. Materials Today:
Proceedings, 39, pp.965–969. doi:https://doi.org/10.1016/j.matpr.2020.04.493 (Mustapha et al.,
2021)