METHOD OF DEVELOPING GEOPOLYMER COMPOSITE, UTILIZING WASTE FOUNDRY SAND, AND CONSTRUCTION AND DEMOLITION WASTE

Abstract

6. Abstract of the invention Title: Method of Developing Geopolymer Composite, Utilizing Waste Foundry Sand, and Construction and Demolition Waste The present invention demonstrates a sustainable geopolymer composite that integrates fly ash, waste foundry sand, and ·C&D waste to develop a sustainable and high-performance construction material. This innovative · geopolymer composite plays viable alternative to conventional cement concrete, potentially lowering carbon impact and advancing waste recycling. The geopolymer composite comprises of 30wt% fly ash, 20-70wt% waste foundry sand, and 0-50wt% C&D waste, which is responsible for material mechanical properties. The resulting geopolymer demonstrates compressive strengths varying from 20 MPa to 35 MPa, impact resistance varying from 15% and 24%, abrasion resistance value ranging from 14% to 22%, and the water absorption rates varying from 6% to I 0%. In line with this, the geopolymer composite exhibits dry densities· varying from 1750 kg/m' to 1950 kg/m'. This invention leads to lowering an environmental impact by recycling industrial byproducts and construction waste and providing an eco- · friendly construction material that fulfils structural integrity, while addressing to resource preservation and landfill waste reduction.

Specification

4. Description:
Title: Method of Developing Geopolymer Composite, Utilizing Waste
Foundry Sand, and Construction and Demolition Waste
Field of the invention
The present invention pertains to sustainable construction materials industry,
10 especially concentrating on geopolymer composites that integrate industrial
waste materials and by-products, which includes fly ash, waste foundry sand,
and construction and demolition ·(C&D) waste. Geopolymers are inorganic
polymeric materials formulated through chemical reaction of aluminosilicate
materials with alkaline activators, providing an alternative environmentally
15 friendly material to conventional concrete, which is accountable for potential
carbon dioxide emissions. By integrating fly ash for its pozzolanic
properties, C&D waste as pozzolanic and fine fillers, and waste foundry sand
as additional filler, this invention addresses critical challenges in waste
management technology and improves resource efficiency. The geopolymer
20 composite improves structural performance, includes compression, impact
resistance, abrasion resistance, dry density water absorption, and
simultaneously facilitating a circular economy by recycling materials that
would otherwise discard 'to landfill as waste. This innovation promotes the
construction materials industry by offering a sustainable solution that lowers
25 the environmental impact of building applications while retaining high
performance and structural integrity .
Background of the invention
Construction industry is a significant contributor to global carbon dioxide
emissions, with traditional Portland cement manufacturing industry is
30 responsible for around 8% of total carbon dioxide emissions. The energyconsuming
method engaged in the extraction, processing, and transportation
of raw materials, integrated with the high temperature requirement for
cement manufacturing; have increased concerns pertaining to the
sustainability of conventional concrete. It leads to an emergence need for
substitute materials that resolves environmental challenges as well enhance
structural integrity.
Geopolymers have emerged as a viable alternative solution for these
challenges. These geopolymer materials are tormulated by activation of ·
aluminosilicate sources, such as fly ash, with alkaline activators. Fly ash, a
byproduct obtained from coal combustion industry, acquires pozzolanic
properties that lead to the formation of durable high strength cementitious
materials. While used in geopolymer formation, fly ash improves
compressive strength and resistance against environmental degradation,
making it a viable alternative to conventional binders.
In addition, waste toundry sand, an industrial by-product obtained during
metal casting processes? leads . potential filler material in geopolymer
composites. Its integration improves workability and mechanical properties
simultaneously reducing the natural aggregate conservation. Waste foundry .
sand usage contributes to resource efficiency and escalates the concerns of
20 waste management by recycling materials.
Further, the incorporation of C&D waste into geopolymer composites offers
a distinct advantage for sustainable construction. C&D waste contains a
mixture ·of materials such as concrete, bricks, and wood, which, when refined
and integrated into geopolymer formation, reduce environmental issues and
25 enhance recycling within the industry. While observing the recognized
advantages of using these· materials are proved, there are limitations m
optimizing their mix design and performance in geopolymer composites .
The present invention aims to confront this limitation by advancing ·a
geopolymer composite that effectively integrates fly ash, waste foundry sand,
30 and C&D waste. By optimizing the mix design and improving the
mechanical properties of the resulting material, this invention contributes to
the sustainable construction practices as well enhance a circular economy, by
offering a pathway towards lowering the environmental impact of the
construction industry.
Objectives of the invention
The main objective of the present invention is to promote an environmentally
sustainable geopolymer composite that efficiently utilizes fly ash, waste
10 foundry sand, and C&D waste, consequently lowering dependence on
conventional cement and· reducing the environmental effect of construction
materials. This invention ·aims to develop the optimal combination of these
components to improve mechanical properties like compression, impact
resistance, abrasion resistance, dry density and water ahsorption, assuring
15 that the composite fulfills or surpasses traditional concrete standards. In
addition, it focuses to enhance resource efficiency by recycling industrial
byproducts and waste materials, aiding to a circular economy and promoting
sustainable construction approaches. Furthermore, the invention seeks to
enhance the knowledge of geopolymer technology and its incorporation,
20 offering future research and development in sustainable construction
practices.
Brief description of prior art
CN 1148533998 (2022) discloses a method for developing recycled concrete
using construction waste. The process involves sorting and crushing raw
25 materials to create coarse aggregates. The fine aggregates, made from
machine-made sand, are treated with a modifier in a specific ratio to enhance
their performance. Coarse aggregates are modified using atlapulgile, a clay
mineral, improving their mechanical properties when incorporated into
concrete. The method uses a direct water addition technique to form the
30 recycled concrete. This approach addresses the challenge of construction
waste disposal by converting waste into high-performance concrete,
enhancing the overall durability and strength of the recycled material.
CN 111995354 A (2020) discloses a reinforced fly ash-based geopolymer and
its preparation method. The geopolymer is developed using a combination of
fly ash, slag, phosphorus slag, a solid alkali activator, quartz sand, Portland
cement, water, and various additives. This innovaiive material demonstrates
excellent construction performance characterized by significant strength
development, minimal shrinkage, no cracking, and effective water retention ..
By fully utilizing fly ash and phosphorus slag, the invention not only
10 enhances the value of these solid wastes but also reduces their environmental
footprint and conserves space. In· addition, the method contributes to
reducing the production costs of geopolymers, leading to favorable social
and economic outcomes.
US 20 I 90092688 A I (20 I 8) discloses fly ash-based geopolymer composites
15 and activating solutions designed for use in concrete applications. The
binders comprises of a mixture of fly ash, silica fume, sodium hydroxide, and
a certain amount of Portland cement. This innovative proportions allows the
resulting concrete to demonstrate superior compressive strength and energy
efficiency while also being more cost-effective compared to traditional
20 concrete options. Notably, incorporating Portland cement enables. a reduction -Q) in the quantities of sodium hydroxide and silica fume required without
C)
Ill compromising the desired compressive strength, making this approach both
D..
Cll efficient and sustainable in concrete production. discloses a method for effective recycling of foundry
25 sand that integrates a water-soluble inorganic binder. The recycling process
starts with the reclamation of the foundry sand, which is bonded with a
powdery magnetic material incorporated into the binder. The method
involves an abrasion process to wear down the recovered sand and remove
the binder from its surface. Followed by, a magnetic separation step is
30 adapted, utilizing a magnet to attract and separate the scraped solid binder
from the foundry sand, extending the magnetic material's performance. This
method not only offers the effective recycling of foundry sand but also
improves the sustainability of the foundry industry by minimizing waste and
promoting resource recovery .
KR20 170022743 A (20 15) discloses a method for producing geopolymers
using industrial wastes as raw materials. The process involves three key
steps: first, preparing an inorganic raw material from various industrial
wastes, including aluminum oxide and silicon oxide; second, creating an
alkaline activator from condensed water generated during seawater
10 desalination, utilizing materials like sodium hydroxide and potassium
hydroxide; and finally, synthesizing the geopolymer through a reaction
between the inorganic raw material and the alkaline activator. This
innovative approach allows for low-cost, efficient production of geopolymers
while effectively reducin-g industrial waste and associated costs, including
"15 those related to landfill sites for coal ash and condensed water treatment.
Additionally, it contributes to the protection of local surface bodies and
aquifers, highlighting its environmental benefits.
CN I 06431028 A (20 15) discloses a geopolymer material made from
construction waste red brick powder and coal ash, emphasizing sustainability
20 in construction practices. The geopolymer utilizes red brick powder and coal -Q) ash as primary raw materials, combined with marine or artificial sand as
C)
Ill aggregates, solid water glass powder as an alkali activator, and metakaolin as
Cll an additive. The specific composition allows for flexibility in proportions,
with the total weight of the raw materials summing to 100%. The preparation
25 process includes steps for blending, forming, curing, and drying the material.
This innovative geopolymer not only maximizes the utilization of
construction waste but also minimizes energy consumption and avoids
pollutant production, presenting a new eco-friendly technique for
construction applications that emphasizes energy savings and reduced
30 emissions.
35
KR I 013061868 I (20 13) discloses a method for manufacturing geopolymer
concrete that increases the use of recycled aggregates without depending on
natural aggregates or sand. The system starts with drying and pulverizing
waste concrete powder, which is later combined with other components such
as blast furnace slag, fly ash, and phosphate in different combination to
create a geopolymer powder. This powder is integrated with recycled coarse
and fine aggregates in determined weight ratios to formulate the geopolymer
concrete raw material. A liquid activator is incorporated to the mix to form
slurry, which is then molded into·concrete and cured. This process improves
compressive strength while promoting sustainability by incorporating
10 recycled materials, thereby lowering dependence on natural resources and ·
lowering construction waste.
CN I 03449744A (20 13) discloses a fly ash-based geopolymer composite
composed of a dry powder phase and water, with a mass ratio of 20:3. The
dry powder phase contains 60-85 parts of fly ash, up to 25 parts of silica
15 fume, I 0 parts of solid sodium silicate, 5 parts of industrial-grade sodium
hydroxide, and a small amount (0.05-0.12 parts) of sodium tripolyphosphate.
This geopolymer acts as a sustainable alternative to cement for developing
engineering materials such as concrete and mortar. Its applications leverage
high-strength thermal mortars, temperature-resistant reinforcement materials,
20 and corrosion-resistant concrete structures. The invention emphasizes the -Q) efficient utilization of industrial waste, particularly fly ash, thereby ·
C)
Ill contributing to resource conservation, energy savings, and environmental
D..
Cll protection. A method for preparing this fly ash-based geopolymer is also
provided, further enhancing its practical utility in construction.
25 CNI03601424 A (2013) discloses on a geopolymeric concrete that utilizes
recycled aggregates sourced from construction waste, coupled with an
inorganic geopolymer adhesive activated through an alkali process. This
innovative concrete exhibits rapid drying capabilities and high early-stage
compressive strength, addressing common issues found in traditional
30 concrete, such as prolonged coagulation times and low initial strength.
f F
Additionally, the geopolymeric concrete showcases minimal volume
shrinkage during curing, with a coefficient of volume expansion near zero, ·
and demonstrates excellent resistance to acid-base corrosion. This method
not only enhances the performance characteristics of concrete but also
effectively tackles the challenges of recycling construction waste aggregates,
contributing positively to environmental sustainability.
KR I 01256834 B I (20 12) discloses a method for producing geopolymer
concrete that utilizes waste concrete micropowder as a key raw material,
enabling the achievement of high compressive strength solely from recycled
10 aggregates. The manufacturing process involves mixing 150-500 parts by
weight of recycled coarse aggregate and im equal amount of recycled fine
aggregate based on I 00 parts of geopolymer powder. Additionally, 30-200
parts of a liquid activator are incorporated, followed by molding and curing
the mixture. The preparation of the coarse aggregate includes steps for
15 removing soil and impurities from construction waste, pulverizing the
aggregate to a size of 40 mm or less while eliminating cement paste, and
further processing the edges of the recycled aggregate using an impact
crusher. This method promotes sustainability by effectively repurposing
waste materials into high-strength construction products.
20 CN201972295U (2011) discloses a construction-waste recycled concrete
hollow block made from construction waste and abandoned rock from iron
mines. The block features a cuboid or square hollow structure with two to six.
uniformly distributed through holes, and its dimensions range from 235-400 .
mm in length, 170-200 mm in width, and I 00-200 mm in height. By utilizing
25 these materials, the invention addresses the scarcity of natural fine
aggregates while promoting environmental protection and resource
sustainability. The hollow blocks are characterized by their low density, high
compressive strength, effective heat insulation, and frost resistance, making
them suitable for both industrial and civil construction applications. The
30 manufacturing process is straightforward and cost-effective, significantly
reducing project expenses and providing a viable alternative to traditional
clay bricks, aligning with the goals of low-carbon, environmentally friendly
construction practices.
CN I 018306738 (20 I 0) discloses a masonry mortar formulated primarily
35 from construction waste. The mortar comprises 15 to 25 percent cement, 25
to 35 percent construction waste micro-powder, 40 to 50 percent sand, 5 to
I 0 percent mineral adniixture, and 3 to 7 percent exciting. agent, all
expressed as percentages by mass. The preparation method includes steps for
creating the construction waste micro-powder, the exciting agent, and the
mineral admixture before combining them to produce the masonry mortar.
10 This innovation significantly contributes to the efficient utilization of
construction waste, mitigating environmental pollution from solid waste
while lowering production costs. Additionally, the resulting masonry mortar
offers advantages of low cost and high strength, making it a practical choice
for construction applications.
15 Detailed description of the invention
20
The present invention ·promotes a novel geopulymer composite that
incorporates fly ash, waste foundry sand, and construction and demolition
(C&D) waste to develop a sustainable building material. This composite
mitigates the increasing need for eco-friendly alternatives to conventional
concrete, which leads to significant· global carbon emissions. By extending
industrial byproducts and C&D waste, the invention lowers the carbon
emission and enhances resource efficiency by recycling materials to avoid
landfill waste. The geopolymer composite formulated via chemical reaction
of alumino-silicate rich fly ash with an alkaline activator offers a sustainable
25 and high-strength material for construction applications.
In the geopolymer composite, the primary binding material is fly ash, a
byproduct of coal combustion, which is activated with alkaline solutions to
form a strong, cementiticius matrix. In this invention, a fixed proportion of
30wt% Class F fly ash, known for its pozzolanic properties, is used for all
30 mix designs, leading to the composite materials mechanical strength and
structural integrity. Waste foundry sand is another industrial byproduct from
metal casting industry, is utilized as an alternative for natural fine aggregate,
enhancing the workability and high compaction of the geopolymer
composite. In this composite, the combination of waste foundry sand varies
from 20wt% to 70wt% and contributing for flexibility in composite's
performance optimization.
In line with this, C&D waste contains refined concrete and brick waste, is
integrated as filler by substituting conventional fillers. This mitigates the
environmental impacts in association with C&D waste disposal and escalates
10 the geopolymer composite mechanical properties. The integration of C&D
waste ranges from Owt% to 50wt% across varies mix combination, focusing
on assessing the pn!cised balance between waste integration and material .
performance. An alkaline activator solution with a sodium silicate to sodium
hydroxide {I OM-NaOH) ratio of 2.5: I is used, and the geopolymer
15 composites are heat-cured at 70°C for 6 hours. The resulting geopolymer
composite illustrates excellent mechanical properties like compressive
strength, abrasion resistance, and impact resistance, making it an ideal
solution for traditional concrete while facilitating to a circular economy by
repurposing industrial byproducts and waste materials.

5. Claims
1/We claim,
I. The present invention pertains to the development of a geopolymer
composite material that integrates flyash, wast~ foundry sand aud C&D
waste as raw materials. The mix design consists of 30wt% fly ash, 20-
70wt% waste foundry sand and 0-50wt% C&D waste. The combination
of these materials lead to environmentally sustainable composite that .
demonstrates superior mechanical properties, such as· enhanced
compressive strength, impact resistance, abrasion resistance, and lesser
water absorption values.
2. As claimed in Claim I, wherein the fly ash adapted is Class F fly ash,
which chemically reacts with an alkaline solution to stimulate
geopolymerization. The alkaline activator chosen as sodium silicate and
sodium hydroxide (IOM-NaOH), with the ratio of 2.5:1, is responsible
for the development of a durable binder composites that adhere to the
structural integrity and stability of the composite.
3. As claimed in Claim I, wherein the C&D waste is pulverized into .
fines. The C&D waste contains materials like crushed concrete, bricks,
and masonry wastes, and its integration in the composite increases the
mechanical properties like compressive strength and durability of the
resulting material, making it viable alternative for structural applications.
4. As claimed in Claim I, wherein the waste foundry sand is utilized as a
filler material that enhances dry density of the composite. The integration
of waste foundry sand facilitates a sustainable method for recycling
industrial byproducts from metal·casting industry, while facilitating to
30 the overall structural integrity of the composite.
5. As claimed in Claim I, wherein 30wt% of fly ash, 50wt% of foundry .
sand, and 20wt% of C&D waste, demonstrates a superior compressive
strength of 35 MPa, an impact resistance of 15%, a water absorption rate
of6%, a density of 1950 kg/m', and an abrasion resistance of 14%.These.·
properties facilitate the composite material viable for use in diverse
structural applications, such as. building components, pavements, and
other load-bearing components, offering both high performance and
10 environmental sustainable materials.
15
6. As claimed in Claim I, including the procedure of mixing fly ash,
waste foundry sand, and C&D waste in specified combinations;
integrating an alkaline activator solution to the composites; and enabling
the composites to undergo elevated temperature of 70°C for 6 hours to
optimize the geopolymerization process. The process results in a
composite material characterized by lowered environmental challenges .
and superior structural integrity.

Documents