Dr. M. R. Kalgal
Past VP, Asian Concrete Federation
Past President, Indian Concrete Institute
Technical Advisor
UltraTech Cement Ltd.
ACCE - SES
7th Nov 2020
Sustainable Development
with
CONCRETE

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A development which
✓recognizes the needs of everyone,
✓maintains stable levels of economic growth and
employment
✓uses natural resources prudently, whilst protecting, and if
possible enhancing, the environment.
Sustainable Development

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Concrete

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Concrete – Sustainable Construction Material
 When considered over its entire life cycle -
extraction, processing, construction,
operation, demolition and recycling - concrete
makes a significant contribution to the triple
bottom line - environmental, social and
economic - of sustainable development.

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Low CO2 intensity
The production of
concrete, which consists of
10% - 15% cement,
results in emissions of
about 0.13 tonne of CO2
per tonne of concrete,
equal to 1/9 the emissions
of cement.
Concrete manufacturing results in less CO2 per unit than almost all other
construction materials, making it the sustainable construction material of
choice.

Making Concrete more Sustainable
➢ Make Cement more Sustainable
➢ Use less energy intensive kilns
➢ Use supplementary cementitious materials to reduce
clinker component
➢ Use new types of clinker
➢ Use alternative fuels and renewable energy during
production process
➢ Produce clinker free cement
➢ Use alternative materials in concrete
➢ Alternative cementitious materials
➢ Use alternative aggregates
➢ Sequester CO2 in Concrete
➢ Produce Clinker free Concrete
Wastes in Concrete – Converting Liabilities into Assets !

Cement
 Popular Statement – Production of 1 MT of Cement
results in emission of 1MT of CO2 to atmosphere
 What is being done?
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Making Concrete more Sustainable

2050 Climate Ambition
 Unveiled on September 1, 2020 by Forty of the world’s
leading cement and concrete companies
 The ambition statement demonstrates the commitment of
the industry across the globe to drive down the CO2 footprint
of the world’s most used man-made product, with an
aspiration to deliver society with carbon neutral concrete by
2050.
 The statement identifies the essential levers that will be
required to achieving carbon neutral concrete, including:
◼ reducing and eliminating energy related emissions,
◼ reducing process emissions through new technologies and
◼ deployment of carbon capture, more efficient use of concrete, reuse
and recycling of concrete and buildings, and harnessing concrete’s
ability to absorb and store carbon from the atmosphere.
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Cement Industry is trying its best to reduce the CO2
footprint
❑ By using efficient manufacturing techniques and alternate
fuels, CO2 emission reduced to around 0.8MT per MT of
cement produced
❑ Switching to manufacture of Blended Cements where Mineral
Admixtures are used, will reduce the OPC content in cement
and hence environmental impact
❑ What “we” can do
➢ In India, majority of “normal” concrete of grades M20 and M25
are still manufactured by volume batching.
➢ Emphasis should be on optimizing the use of cement by going
in for mix proportioning.

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LC3 Cement – the green cement
Limestone Calcined Clay Clinker Cement
❑ When used together, the aluminates from the calcined clay
interact with the calcium carbonates from the limestone,
leading to a less porous, and therefore stronger, cement paste
❑ Now, an EPFL-led consortium has received backing from the
Swiss Agency for Development and Cooperation (SDC) to speed
up the development and testing of a new blend of low-carbon
cement. Elaborated with partners from the Indian Institutes of
Technology and from universities in Cuba and Brazil, this new
blend substitutes up to half of the usual Portland cement used
to make concrete with highly abundant clay and limestone,
promising to reduce cement-related CO2 emissions by up to
30%.
Courtesy Dr. Karen Scrivner

Courtesy Dr. Karen Scrivner

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✓ With current clinker production facilities, production capacity
for cement can be increased twofold without increasing total
CO2 emissions.
✓ Quarry life can then be considerably extended and costly
Carbon capture and storage technologies for emission
abatement can be avoided.
✓ Emissions of LC3 are estimated to be 20-30% lower than
Portland cement because:
➢ Reduced clinker content leads to less process emissions from the
decarbonation of limestone in clinker and less emissions from heating
limestone to form clinker
➢ Grinding limestone takes less energy than heating it
➢ Calcination of clay takes place at 800°C and uses roughly 55% of the
energy needed for clinkerisation at 1450°C.
LC3 allows growth without abstinence due to
resources and CO2 efficiency
Courtesy Dr. Karen Scrivner

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Lower cost of production
Reduced clinker content, decreased fuel consumption for calcination compared to
clinker plus the fact that limestone does not need to be heated should contribute
to lower production costs. Lower production costs are one of the main drivers for
technology uptake.
A well-known technology
Clinker–Limestone systems and Clinker–Calcined Clay systems are well established.
In effect, LC3 is optimises the synergy between two already known chemical
systems. This leads to a higher degree of confidence that the materials will be
durable since the chemical nature of the hydrates and pore structure are similar to
other blended cements which have proven durable.
Resource efficiency
Using low-grade clay and limestone does not require opening new quarries nor
deplete agricultural soils.
.
Existing equipment can be used
LC3 can be produced with existing manufacturing equipment, leading to only
marginally increased investments for calcining equipment.
Courtesy Dr. Karen Scrivner

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Sustainable Aggregates
➢ Recycled Aggregates:
➢ Construction and Demolition Waste
material (C&DW) and
➢ railway ballast.
➢ Secondary Aggregates:
➢ manufactured and natural
Alternatives to Sand
❑ Crushed Stone Sand
❑ Manufactured Sand
❑ C&DW Sand
❑ Marine Sand
❑ Industrial wastes viz. Pond Ash
Making Concrete more Sustainable

Procedure followed in effective utilisation of Alternate Sources
❑ Characterization of materials
➢ Physical
➢ Chemical
❑ Study of Concrete made with alternative materials
➢ Fresh State
➢ Hardened State
❑ Study of effects on long term properties and durability
❑ Development of mix design and QA/QC procedures

Durability of Concrete
Ability to resist weathering action, chemical attack,
abrasion or any other process of deterioration while
retaining its original form, quality, and serviceability when
exposed to its environment during its design life
Durability is the key to sustainability. If the useful life of a
structure can be extended by using concrete, that's a huge
gain for sustainability.

What Influences Durability of Concrete?
Durability
Concrete
System
Materials
Processing
Service
Environment
Physical
Effects
Chemical
Effects

What Influences Durability of Concrete?
 Concretes are said to be less durable when they
are physically or chemically compromised.
 Physical factors can result in chemical reactions
reducing durability
◼ e.g Cracking due to shrinkage can allow reactive gases
and liquids to enter the concrete
 Chemical factors can result in physical outcomes
reducing durability
◼ e.g. Alkali silica reaction opening up cracks allowing
other agents such as sulfate and chloride in seawater
or CO2 to enter.

Is durability an issue for Concrete with
Alternate Materials?
Yes and No

Is durability an issue for Concrete with
Alternate Materials?
Yes
 Problem
◼ Less understanding of the properties of alternate materials
◼ Less control on the properties (and quality) of alternate
materials
◼ Less understanding of the impact of alternate materials
 Consequence
◼ Undesirable interactions with other ingredients
◼ Altered fresh concrete behaviour
 Reduced workability, excessive bleeding, reduced slump retention
excessive shrinkage cracks etc.
◼ Altered/impaired hard concrete behaviour
 Reduced permeability, reduced strength, delayed ettringite

Is durability an issue for Concrete with
Alternate Materials?
No
 Issues can be overcome by
◼ Proper study of the properties of alternate materials
◼ Following a vigorous Quality Assurance system
◼ Ensuring
 Proper mix design procedure
 Strict monitoring of site practices
 Proper compaction
 Adequate curing
 Result
◼ Much denser and impermeable concrete
◼ Concrete with lesser environmental impact
◼ Concrete with lesser life-cycle cost

Courtesy Vladimir Ronin

✓ Worldwide, hundreds of companies and research groups are
working to keep CO2 out of the atmosphere and store it
someplace else—including in deep geologic formations,
soils, soda bubbles, and concrete blocks.
✓ By making waste CO2 into something marketable, entrepreneurs
can begin raising revenues needed to scale their technologies
Upcycling CO2

Nanomaterials derived from the use of CO2
 Carbon Upcycling technology transforms residues such as fly
ash and slag, making them more reactive and increasing their
cementitious properties.
 The use of CO2 previously captured, combined with a physical
transformation of the material during the process, generates
a new addition for the cement that allows the production of
concrete with a low environmental footprint.
 The improvement in the cementitious capacity of materials
achieved by the Carbon Upcycling technology will expand the
range of sources that can be used to reduce the amount of
clinker needed in cement production and the amount of
cement required in concrete.

Carbon Capture
 CO2 Concrete’s process locks flue gas CO2 into limestone
within CO2 Concrete™.
 The process requires minimal CAPEX, since it features simple
“stack-tap” integration with limited site utility tie-ins, does
not require a carbon capture system, and readily integrates
into existing construction supply chains and workflows.
 Additionally, CO2 Concrete™ mixtures can incorporate low-
value fly ashes, including those reclaimed from landfills and
ponds, while providing engineering performance equivalent
to typical concrete.
 The low cost of CO2 Concrete™ is a significant advantage in
the low margin concrete business.

❑ Patented process from USA based Solidia Technologies
❑ A low-lime calcium silicate (Ca2SiO4) cement (CSC) that cures by a
reaction with gaseous carbon dioxide (CO2).
❑ The production of CSC requires less limestone and lower kiln
temperatures than those used for ordinary Portland cement
(OPC). This makes it possible to reduce the carbon dioxide
emissions at the cement kiln from ∼810 kg/t for OPC to ∼565 kg/t
for CSC.
❑ The carbon dioxide used in the curing process and captured
within CSC-based concrete (CSC-C) is industrial-grade carbon
dioxide sourced from waste flue gas streams.
These translate to approximately 30% reduction in CO2 emissions.
Carbonated Calcium Silicate Concrete

ZERO Clinker Cement

Step 1 :Valorization (Conferring value upon something)
Recover and enhance co-products from industry and construction,
which are sent to production plant :
✓ Blast furnace slag comes from the metallurgical and steel industry
✓ Flash clay is a co-product of clay sludge
✓ Gypsum/Desulfogypsum are produced from construction site excavated
material.

The manufacturing process based on
the systematic use of abundant co-
products as a substitute for natural
resources. The co-products, are
mixed with activators and
superactivators specifically
formulated .
This is followed by the packaging of
cements (big bag, bulk or bags) and
then shipment to the construction
sites
Step 2 : Production

These cements are used to serve the three main cement markets:
➢ Precast concrete
➢ Ready-mix concrete
➢ Retail Sale
Step 3 : Use in Construction

ZERO Clinker Cement

H-P2A cement
Activators and superactivators formulated are added to flashed clay
mixed with silicate to obtain H-P2A cement.
• pull-out strength of more than 25 MPa.
• based on activated clay and silicate in the form of a two-component
“paste & liquid” system.
• a 100% mineral, non-flammable and VOC -free adhesive.
Solution based on the use of blast furnace slag. Efficient activation
system allows this co-product to be used without any addition of
clinker in its formulation.
Used in various fields of construction, including “ready-mix
concrete” and “precast concrete”.
H-UKR cement

Application of
H-UKR
cement
developed by
Hoffmann
Green

H-EVA cement
➢ An innovative binder, H-EVA is an alkaline ettringitic technology.
➢ Activators and superactivators formulated are added to flashed
clay, mixed with gypsum/desulfogypsum to obtain H-EVA cement.
(Gypsum from industrial processes, such as desulfogypsum or phosphogypsum,
are currently still little upgraded)
➢ H-EVA cement has a mechanical strength of up to 60 MPa at 28
days.
➢ H-EVA is ideal as a road binder, but can also be used for mortars,
plasters and construction concretes.

ZERO Cement Concrete
❑ Concrete corrosion and fatbergs plague sewage systems
around the world, leading to costly and disruptive
maintenance (Fatbergs are gross globs of congealed mass clogging
sewers with fat, grease, oil and non-biodegradable junk)
❑ A Zero cement composite of nano-silica, fly-ash, slag and
hydrated lime is developed at RMIT Australia.
❑ Zero-cement concrete achieves multiple benefits:
✓ it’s environmentally friendly,
✓ reduces concrete corrosion by 96 per cent and
✓ totally eliminates residual lime that is instrumental in the
formation of fatbergs
❑ “With further development, it is claimed that zero-cement
concrete could be made totally resistant to acid corrosion.”

Sequestering CO2
➢ CO2 captured from existing industrial emitters, purified, stored,
and distributed to concrete producers in pressurised tanks.
➢ Liquid CO2 injected into the wet concrete mix,
➢ CO₂ reacts with calcium ions from cement to form a nano-sized
mineral, Calcium Carbonate, which gets embedded in the
concrete.
➢ Result –
✓ Stronger concrete
✓ mix optimization – redn. in cement consumption
✓ Consumption of CO₂. (~500MT/yr)
• The technology can be retrofitted into existing concrete plants
• Introduction of the CO2 does not impact the concrete’s
workability, air content, freeze-thaw performance, pH, density,
durability, air content, colour, texture, or finish
CO₂ Mineralization

Protecting Concrete
 Carbon Upcycling Technologies (CUT) has introduced a
nanotech coating called AlphaCarbon, which protects
materials like concrete against acids and corrosion.
 It's just one of Sinha's efforts to convert carbon dioxide into a
range of solid nanoparticles, useful for all manner of
materials.
 The AlphaCarbon coating is installed in over 250 locations
across the US, including franchises of McDonald’s, Costco, and
Walmart.

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Concrete and
Materials for Concrete
in Indian Context
❑Concrete construction practices are significantly different in India
in comparison to developed countries.
❑Even now majority of concrete produced and used in India is by
the unorganized sector.
❑Virtually no awareness about the sustainability aspects.
❑Env. regulations – inadequate/not enforced effectively.
❑Engineered or semi-engineered constructions - limited to larger
housing or infrastructure projects.
❑The use of Ready Mix Concrete (where there is likelihood of
optimal use of materials) - just above 10 percent of the total
concrete produced
❑Need to minimize wastage of precious natural resources by making
their efficient and judicious use.

Concluding Remarks
 Construction industry has a large role to play in Sustainable
Development.
 The drive towards more Sustainable Construction is
achievable only when all the stakeholders in the industry,
including developers, designers, builders and suppliers
recognize and appreciate its importance.
 Concrete being the most ubiquitous construction material, it
is necessary to make it as sustainable as possible.
 Durability is one of the important pillars of Sustainability
 Design for durability followed by selection of proper materials
and their combination supported by systematic QA/QC
procedures can ensure a durable and hence Sustainable
Concrete