Exploring the Cost-Effectiveness of Cellular Concrete in Large-Scale Projects
Cellular concrete is essential for insulation, fire & mold resistance, and structure. Wall panels, lintels, blocks, and floor and roof panels are cellular concrete products. It comprises a range of dry densities, ranging from 400kg/m cube to 1600 kg/m cube, along with a range of compressive strengths from 1 N/mm2 to 15 N/mm2. This concrete is versatile because it is tailored for optimum performance and minimum cost by choosing a sustainable mix design. Different factors are responsible for driving market growth, such as the acceleration of urbanization, followed by the growth of infrastructural activities, and the increase in industrialization. Moreover, the growing spending capacity of people from developing economies and the increasing incomes supported by the growing demand by end-user sectors such as residential buildings, infrastructure, and commercial buildings are also major factors playing an imperative role. Cellular Concrete, in this regard, has multiple uses in different end-use industries.
The growing use of Cellular Concrete in the Construction/Infrastructure Industry
Cellular concrete is efficiently used in the construction sector mainly because of its properties, such as providing fire and mold resistance, structure, and insulation, which are essential factors. They are also used as roof and floor decks and in geotechnical applications such as for void fill abandonment and annular space filling in slip lining. A few of the most common applications for cellular concrete revolve around soil remediation, in which case, when there are poor subsoil conditions, cellular concrete is used to efficiently create a stronger base while reducing the burden on subsoils. They are also used for utility trench fill, flowable fill/geofoam alternative, bridge/overpass abutment fill, culvert trench fill, retaining wall/MSE wall backfill, floor decks, fence panels along highways, roof decks, precast specialist, interior walls, retaining wall base, sidewalks, patios and porch decks, carved concrete sculptures among many more.
- According to Invest India, India’s construction industry is expected to reach $1.4 trillion by 2025. Furthermore, by 2025, India is expected to generate at least 70% of its GDP through the construction field, which works around 250 sub-sectors with linkages across different sectors. In terms of residential construction, it is expected that by 2030, approximately 600 million people will be living in urban areas, creating a demand for 25 million additional affordable and mid-end units. Moreover, under NIP, India has a total investment budget of $1.4 trillion divided among different sectors. Out of this $1.5 trillion investment budget, 24% will be for renewable energy, 18% for roads and highways, 17% for urban infrastructure, and 12% will be for railways. Not only this, but under a Technology Sub-Mission of PMAY-U, a new era of the Indian construction technology sector will start with over 54 global innovative construction technologies. These factors combined will drive the demand for cellular concrete in India’s construction industry.
- According to TST Europe, in the United States, the construction industry is imperative, encompassing over 745,000 companies that will be essential in providing employment opportunities to 7.8 million people annually. Additionally, total construction spending in 2023 reached $1.98 trillion, which was also a 7.4% increase from the previous year.
- According to the International Trade Administration, China is regarded as the world’s largest construction market, impacted by government regulations and policies. The introduction of China’s 14th Five-Year Plan was a step forward toward the growing construction and infrastructure industry in energy, water systems, transportation, and new urbanization. In this regard, the overall investments done by China in its new infrastructure period during the 14th Five-Year-Plan period (2021-2025) will reach 27 trillion yuan ($4.2 trillion), which will drive the construction industry, further resulting in market growth.
- According to Germany Works, one of Europe’s biggest construction markets is Germany, which encompasses the continent’s largest building stock. In 2021, the industry’s revenue increased by 5.9 percent, reaching Euro 143 billion. The construction market in Germany is also expected to increase with the increasing annual investments, which have been growing since 2015.
4 Advantages of Cellular Concrete
Cellular concrete, also known as mini-concrete, is obtained from cement, water, and a foaming agent. This concrete is gap-voided and thus has a very low density. It remains the best choice for thermal and sound insulation in building construction where sustainable options are required. Designers and contractors of buildings today are looking forward to ways how to minimize and reduce the effects of construction on the environment, and the cellular concrete option has been embraced, especially in the construction of homes and business establishments that seek to have less energy consumption and, therefore, less emissions. These cellular concrete possess certain advantages when it comes to restoration projects or buildings, such as:
- Lighter Weight: Cellular concrete’s defining feature is its relatively high air content. Evenly distributed air cells are left behind in the hardened concrete, where the air may account for up to 80 percent of cellular concrete’s volume. This said, the contractor can carefully adjust the precise ratio of the foam that is introduced to control the amount of air and end up with the desired density. Cellular concrete is essential as it allows the builders to stay within the strict weight management limits for specific types of buildings. In contrast, the lightweight feature can even be used as a roofing material.
- Better Thermal Insulation: Cellular concrete has a high air content, which has a drastic effect on thermal insulation. Similarly, like density, there is a direct proportion of insulation power and the proportion of air in the concrete. As a result, the structures that are built using cellular concrete tend to exhibit much better energy efficiency. In this regard, one-inch standard concrete with a density of 150 pounds per cubic foot has an R-value of just 0.07. Meanwhile, cellular concrete at the end of the spectrum constitutes an R-value as high as 2.0 per inch.
- Improved Fire Resistance: There is a natural desire for fire resistance in all concretes. Yet, not all concrete can withstand the same temperatures or for equal lengths of time. Concrete’s insulating properties make it a great choice for energy efficiency while improving its ability to resist heat transfer, making it harder for fire to spread through buildings.
- More Cost-Effective: Fly ash is an imperative ingredient in cellular concrete, promoting a greater degree of internal strength. Fly ash is regarded as a replacement for some cement, thus bringing down the overall cost of the concrete. This is mainly because fly ash is an industrial waste product that can be acquired at a fraction of the cost of cement, thus making it cost-effective and efficient.
Fly ash is produced at a Coal based Thermal Power Plant. Sustainable FlyAshutilization is regarded as one of its activities’ thrust areas at all NTPCs Coal Based PowerPlants. To provide momentum for its FlyAsh Utilization, a separate Ash Utilization Group was set up in 1991. Such developments have resulted in all coal-based stations consisting of dedicated groups responsible for Ash Utilization activities in which the group strives to achieve 100% Ash Utilization sustainably.
Concrete Consumption in Different Regions
According to the US Geological Survey (USGS), the United States produced an estimated 95Mt (million tonnes) of Portland and masonry cement in 2022, which was up from 93Mt in the previous year. In 32 states, cement was produced at 96 plants, along with two plants in Puerto Rico. Among those 32 states, Texas, California, and Florida were the leading cement-producing states, accounting for approximately 43% of US production. Furthermore, US cement consumption (production + imports) was estimated at 120Mt in 2022 compared to 110Mt from the previous year.
Moreover, according to the USGS data, there was a fall in the world’s cement consumption from an estimated 4.4bnt in 2021 to 4.1bnt last year. Whereas the gains over the same period were seen in India, where the production of cement advanced from 350Mt to 370Mt, Russia (61Mt to 62Mt), Turkey (82Mt to 85Mt), and Vietnam (110Mt to 120Mt).
Furthermore, according to the Ministry of External Affairs, Government of India, a report was published by the Union Miniter of Commerce & Industry on “The Cement Industry- India,” which was prepared by the National Council for Cement and Building Materials (NCCBM), in association with the cement section of Department for Promotion of Industry and Internal Trade (DPIIT), stating that India’s cement industry is regarded to be the second largest in the world consisting of the annual installed capacity of around 509 million tonnes, accounting for a total cement production of 298 million tonnes which were reported from 143 cement plants, 5 clinkerisation, 102 grinding units and 62 cement planta across the country. Thus, India, known to be the fastest-growing major economy, offers strong growth metrics for cement production. In this regard, the increasing demand from the growing infrastructure and housing projects in India has ensured steady growth for the industry.
Fly Ash Cellular Lightweight Concrete Properties and Uses
One of the latest emerging technologies in concrete making is cellular lightweight concrete, which has multiple benefits over conventional concrete. Fly ash is a waste product of thermal power plants that cannot be disposed of easily. This solves the issue of disposable fly ash as it can be used in the construction industry mainly because of its properties and its most important cost-effective feature. The fly ash-based CLC is produced with low energy and is environment-friendly. Furthermore, the density of the fly ash-based cellular lightweight concrete is lower than normal concrete, but its strength is the same.
Fly ash cellular lightweight concrete is a version of lightweight concrete produced like normal concrete under ambient conditions. It is also manufactured by mixing cement, sand, fly ash (26%-24% content), and water. Additionally, fly ash is regarded as the waste product from thermal power plants for over 25% constituent material, and it can have more than 25% (26% to 33%) of the total solid material constituted of CLC mixed for different density outputs. On the other hand, the benefits of lightweight cellular concrete revolve around fireproofing, soundproofing, and termite-proofing, along with being thermally insulated and environment-friendly.
Adoption and Penetration of Cost-Effective Lightweight Cellular Concrete in the United States
Lightweight Cellular Concrete is a strong, durable, and inexpensive soil or fill replacement for various geotechnical applications. In this regard, LLCs in a geotechnical environment can be utilized for various purposes, such as road bases, void, cavity filling, and bridge approach embankments. In the United States, for the fiscal year of 2024, an investment of $61 billion was initiated by the Federal Highway Administration for 12 formula programs which would result in being imperative in critical infrastructure, including bridges, roads, tunnels, safety improvements as well as for the reduction of carbon emissions. Moreover, as per the Dodge Construction Network, the infrastructure bill will support the public-sector consumption projects outpacing the private sector in 2024.
Furthermore, highway and bridge construction in the United States is expected to increase by 23%, resulting in $147.2 billion in 2023, which would be regarded as the largest gain of any construction sector. This further follows a 14% increase to $119.5 billion in 2023. According to the American Road & Transportation Builders Association, highway construction in 2023 continued to increase, resulting in a total highway activity value of $9.2 billion in November, a 16% increase compared to November 2022. The year to date was also up by 17% compared to 2022, resulting in the value of work being $102.8 billion. Not only this, but the construction of bridges also increased by 14%.
Since lightweight cellular concrete plays a major role in the construction of bridges, the increase in the funding of various projects by the Infrastructure, Investments, and Jobs Act 2021 (IIJA) in the construction phase will also act as a growth driver. In this regard, the Infrastructure, Investments, and Jobs Act has started funding major projects and has further stepped up their investment in transportation infrastructure through business taxes, bond issues, user-fee increases, and general-fund transfers as per the American Road & Transportation Builders Association. These investments by IIJA will thus result in increased construction value and overall market activity. Additionally, the total value of the transportation construction work in the United States in 2024 is expected to grow by 14%, reaching $214 billion. combined will result in the growth of effective, lightweight cellular concrete that serves multiple advantages.
Application and Benefits of Cost-Effective Fly-Ash in Comparison to Conventional Concrete
Conventional concrete is regarded as a conglomerate of hydraulic (Portland) cement, stone, sand, and water, which was developed approximately 150 years ago to imitate natural stone while providing less labor-intensive methods of shaping the materials (i.e., casting rather than hewing and carving). Additionally, cellular concrete exhibits multiple advantages over conventional concrete in terms of its thermal stability, less energy-consuming manufacturing process, and, most importantly, the easiness and cost-effectiveness of using lightweight cellular concrete. Moreover, economically, cellular concrete weighs between 10% and 87%, which is less than conventional concrete.
According to the Federal Highway Administration under the U.S. Department of Transportation, lightweight fly ash, a by-product of cellular lightweight concrete, is preferred over conventional concrete, mainly Portland cement, due to its properties and the multiple benefits it serves. One such benefit is its cost-effectiveness, which allows fly ash to be used in different end-user industries. Fly ash is used in concrete to improve the workability of plastic concrete. Regarding improved workability, the spherical particles of fly ash act as miniature ball bearings within the concrete mix itself, providing a more lubricant effect. This same effect also improves the concrete pumpability by reducing frictional losses during pumping and flat work finishability.
Moreover, the replacement of cement with fly ash also results in the reduction of water demand for a given slump. For instance, when fly ash is used at about 20% of the total cementitious, it results in an approximately 10% reduction in water demand. This reduction in water demand further has little or no effect on drying cracking/shrinkage. These replacements also support the reduction of the heat of hydration of concrete, which is beneficial mainly because this reduction does not sacrifice the long-term strength gain or durability, making it an ideal choice of cost-effective concrete.
As a result, fly ash is widely used as a replacement for concrete, firstly because of its cost-effectiveness and secondly because it is a constituent of reinforced concrete. It also replaced the Portland cement partially or fully in a few cases. Especially in the case of Japan, fly ash is widely used because Japan is known to be an earthquake-prone area. In this regard, the use of fly, compared to cement, lowers the risk of aggressive chemical reactions on hardened concrete, making it more durable, reliable, and resilient.
According to the Center for Disaster Philanthropy, on the first day of 2024, Japan was hit by a magnitude of 7.5 earthquake recorded by the U.S. Geological Survey (USGS) near the northern coast of the Noto Peninsula on the west coast of Honshu, Japan. According to a research paper published by experts at Japanese Universities, from November 2020 to February 2023, at least 14,000 small earthquakes occurred off the Noto peninsula in seismic swarms of 1 or more.
Figure 1: Top Earthquakes in Japan, Regions and Their Magnitudes, 2021 to 2023
Source: World Data
