How can you make concrete more energy-efficient?

It is common in the Middle East to use a cement replacement of up to 70% in the substructure for durability and reduce carbon footprint In a recent initiative, up to 50 % is being used for the superstructure to reduce carbon footprint Common cement replacement materials are GGBS, Micro Silica and Fly Ash.

Behind drinking water, concrete is the most used man-made material on earth, with 14 billion m3 produced each year. Hence, the production of cement, the active binding agent in concrete, accounts for around 7% of global CO2 emissions, whilst cement production is responsible for almost 60% of the embodied carbon in reinforced concrete. Thus, with 2050 rapidly approaching, action must be taken to reduce emissions and realise net-zero commitments. The 3C’s of Innovation in Low-Carbon Concrete, examining decarbonising solutions across the clinker, cement and concrete production stages. Discussions with concrete suppliers & the engineer to optimise carbon of conventional concrete can lead to immediate savings of between 5 - 15%.

There are many things where global cement industry is focusing -1) Use of SCM like fly ash, GGBFS, lime stone powder,rice husk,metakaolin etc 2) Experiment with Hydrogen 3) Using solar energy 4) Using more than 100 typrs by products which are considered as waste 5) Adopting advances in modern technology 6) Using AI for maintainance of plant & machines 7)Using synthetic gypsum & substitutes of mineral gypsum 9) Focus on R & D 10) Improving PSD 11) Using grinding aids 12) Using PP fibres 13) Reducing water consumption in final product application

1. Use of Fly Ash, Slag Sand. 2. Optimizing Mix Design to Reduce OP Cement with Hydraulic Lime. 3. Improvement in Construction practices and techniques. These are some of the steps which can contribute to energy efficiency in Concrete Production.

Le sujet de la fabrication du béton est complexe, impliquant non seulement l'énergie utilisée mais aussi les matières premières et l'usage final. Bien que le béton à faible empreinte carbone réduise la consommation énergétique, il faut également considérer le transport et la transformation des matières premières. L'ajout de Graphène dans le béton peut accro?tre sa résistance, mais cela réduit-il réellement l'énergie totale nécessaire à sa fabrication? Comparer les avantages du béton avec ceux des matériaux naturels comme la pierre, le bois et la terre en termes de consommation énergétique et de biodiversité est crucial dans la planification urbaine.

You can opt High Performance Concrete for M 20 also .It is good way to reduce energy in manufacting concrete.But try to use locally available material which can reduce your CO2 during transportation.More focus should be on quality & grading of aggregates

HPC is commonly used in the construction of high-rise buildings, bridges, dams, and other structures that require exceptional strength and durability. It is also an eco-friendly option as it can reduce the amount of material needed in construction and decrease the carbon footprint of a building.

The use of HPC, VHPC, UHPC etc. is common in bridge building today. It allows for more efficient designs and better long term bridge performance.

HPC offers several advantages, including high compressive strength. HPC allows thinner columns in high-rise buildings, bridges, and post-tensioned structures. However, I think at least two key factors limit it: 1- Slenderness: Narrow columns can buckle under load. Therefore, dimension reduction is limited in his way. 2- Moment capacity: In massive concrete structures like dams and retaining walls, the bending moment governs the design. In these cases, the strength of the concrete has a minimal impact on the dimensions. An effective strategy is using HPC for the facing to protect durability issues, while a lower-strength core can provide sufficient filler. Using core concrete reduces cement usage and consequently lowers CO2 emissions.

High performance concrete is more efficient. To achieve proper strength you need to design a concrete mix according to your needs.

In the UAE, the concrete industry is exploring ways to enhance energy efficiency in concrete production by recycling waste concrete from demolitions. This recycled concrete is repurposed as aggregate for new concrete or as sub-base material for roads, thereby reducing the demand for new raw materials and diverting waste from landfills. However, it’s essential to ensure that recycled concrete meets the necessary specifications and standards. Despite potential variations in quality, with meticulous processing and stringent quality control, we can pave the way towards a sustainable, energy-efficient future in the concrete industry.

Concreting with aggregates from debris is gaining momentum. However it is to be carefully done because with an increased specific surface of aggregates, the cement consumption would go high. Making it in workable consistency would then need specific construction chemicals. Air entraining chemicals could be a good option for the purpose.

To achieve sustainable construction goals, optimizing concrete's energy efficiency is crucial. Here's how: 1. Material Innovation: Incorporate supplementary cementitious materials like fly ash to reduce cement usage and carbon emissions. 2. Mix Precision: Fine-tune mix designs with lower water-to-cement ratios for stronger, more durable concrete, reducing energy consumption during production and transport. 3. Tech Integration: Implement carbon capture during cement production to minimize greenhouse gas emissions. 4. Insulation Focus: Improve thermal performance with insulating materials in structures to lower heating and cooling needs. #Concrete #Sustainability

Recycled concrete can be used for a variety of applications, including road construction, landscaping, and building foundations.

High-performance concrete could be defined as concrete with strength and durability significantly beyond those obtained by normal industry practice. The required properties for concrete to be classified as high performance therefore depends on the properties and elements of normal concrete achievable at a particular location.

Concrete can be made more energy-efficient by adding additives like fly ash or slag, which lower the embodied energy of the material by reducing the amount of cement required. Using recycled aggregates also lessens the impact on the environment. The ability of a substance to absorb and retain heat, hence reducing temperature swings, is referred to as its thermal mass. Because concrete has a high thermal mass, it can be strategically used in building to control indoor temperature and minimise the need for additional energy for heating or cooling.

This property is often used in building design to help regulate indoor temperature and reduce heating and cooling costs. For example, a thick concrete wall can absorb heat during the day and release it at night, helping to keep the interior of a building cool during the day and warm at night.

Thermal mass is the ability of a material to absorb, store and release heat. Thermal lag is the rate at which a material releases stored heat. For most common building materials, the higher the thermal mass, the longer the thermal lag. Thermal mass should be placed where it will best be able to absorb heat in the colder months and be shaded in the warmer months. Herewith a list of thermal mass examples: Materials such as concrete, bricks and tiles absorb and store heat.

Concrete mass slows down the passage of heat moving through the wall. This means with the same insulation a concrete home stays warmer in the winter and cooler in summer than wood frame houses

In my opinion, smart concrete is an ongoing development in the construction industry. It involves integrating properties that allow concrete to respond to changes in its environment, by doing this, the functionality and sustainability of the concrete is enhanced. For example, certain types of smart concrete can improve energy efficiency in a building by storing heat or by optimizing light reflection. For example, temperature-regulating concrete can absorb and store heat from the sun and release it slowly over time, this would help to regulate the temperature inside buildings and reduce heating and cooling costs.

Smart concrete has the potential to revolutionize the construction industry by increasing safety, reducing maintenance costs, and extending the life of structures.

Very important point. This is discussed and addressed in adequate depth in my book "Sustainable Construction Practices'. Green concrete is free from contaminants and manufactured with the majority of natural resources.

Unless you are changing the composition of the chemistry the term low energy should be replaced with green or low impact energy - the calcination of the raw materials and the fuel burn for the grinding and the heating of the process of cement making are the 2 energy inputs which have highest contribution - the transport of concrete and its ingredients is a secondary energy source but also has opertunity for reduction.

Precast Concrete: By molding concrete in a controlled factory setting, precast concrete reduces waste and energy consumption during curing. Supplementary Cementitious Materials (SCMs): Using SCMs like fly ash, slag cement, and silica fume can replace part of the Portland cement, reducing energy-intensive production and CO2 emissions. Carbon Capture, Utilization, and Storage (CCUS) Energy-Efficient Production Methods Recycling and Reusing Concrete

One thing I have found helpful is the integration of 3D printing technology into the production of concrete structures. 3D printing of concrete would allow the precise placement of concrete, thereby reducing waste and optimizing the use of materials. Traditional construction methods often result in excess materials that are always being discarded. In the case of 3D printing, the volume of concrete to be used can precisely be controlled by placing it only where needed and thus minimizing waste. This precision not only saves materials but also reduces the energy consumption associated with producing and transporting excess concrete.

Even after considering all of the above points, in my view the most important thing to make concrete more energy efficient is basically to reduce the energy lost in producing and transporting concrete by equipment which have been invented almost 100 years back. We waste a huge amount of energy in producing wet concrete and keeping the wet concrete alive four hours together during transportation. This energy increases the carbon footprint of concrete which is ultimately delivered to the consumer. Presently this energy is obtained mostly by burning fossil fuels in the engines.

Further to Sergio Marletta's previous post noting concrete to be simply too CO2 intensive, of which I am fully in agreement, however note further mitigation measures to reduce embodied carbon in new constructions. In foundation works, do we really need to produce concrete with a 28-day strength, when the foundations will not be loaded immediately. Noting this, foundation concrete should be specified at a 75-day strength The use of supplementary cementitious materials in a concrete mix will become frequent by time, due also to greater production will reduce prices for energy saving cements. On the other hand in precast work where early setting of concrete is required, it is presently difficult to adapt to a mix whereby this is achieved.

Low carbon concrete consists of industrial cement combined with mineral compounds, such as calcined clays, fly ash or blast-furnace slag. This been the waste materials from furnace and boiler.

'Green costs more' any phasing out innovation is initially cost intensive as a precedent in industry till mass acceptance is seen and a paradigm shift of the entire manufacturer's and contractors mechanism shifts in favor. Till then creasing out the issues related to delivery, mixing, setting times and sourcing/processing of the raw materials are on a backseat which are directly related to scalability and growth. Globally the governments are gearing up to reduce carbon emission targets by providing subsidies and encouraging growth of green/ sustainable materials. India is an eager participant in the process and the current ruling govt is leading form front. This hopefully should bring in the change to prove that 'Green costs more' wrong.