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Strategic Technologies of Complex
Environmental Issues-A Sustainable Approach - ISBN: 978-93-83083-85-5 85
Paper Crete: A Sustainable Building Material
Jil Tushar Sheth
1
, Saransh Joshi
2
1,2
CEPT University, Ahmedabad, Gujarat, INDIA
Abstract: Paper Crete is kind of fibrous cement, made by shredding paper (old newspapers,
prints, cardboards etc.) into pulp in water and adding Portland cement to it and in some cases
sandy soil to be used as an additive. It gains its inherent strength due to presence of hydrogen
bonds in microstructure of paper. This thick mix can then be poured into molds and cast like
concrete, to make it into any desired shape and size. Papercrete is a sustainable building
material due to reduced amount of cement usage and recycled paper being put to good use. It
has numerous advantages in construction industry, namely low carbon footprint, recycled
material usage, low embodied energy, high strength to weight ratio, high thermal insulation,
high sound absorption, aesthetic and cost effective. Much research is being carried out globally
on the material but it is yet to be acknowledged by Indian standard practices and codes and
recognized by major building material organizations in India.
This paper is based on the findings done in a study which was undertaken as a part summer
school course work done in this area at CEPT University and illustrates the methods adopted for
manufacturing building blocks, studying mechanical properties and construction technology
associated with papercrete building blocks. It also looks into the applications, limitations and
possible modifications by way of admixtures to overcome some of these limitations.
Keywords: Paper Crete, sustainable construction, building blocks, recycled material
1. INTRODUCTION
Papercrete is a recently explored construction material that consists of re-pulped paper fiber with
cement or clay. It is an experimental material that replaces a certain proportion of cement with
paper in the normal concrete mix. It is perceived as an environment friendly material due to the
vital recycled content. By doing so, the total weight, cost and the carbon emissions during
production are reduced. Its use remains limited, because of the lack of official data about its
structural properties, mechanical properties and durability. In order to establish papercrete as a
standard material, further experimentation is needed.
As nominal mix has not been defined yet and guidelines for mix design of papercrete are not yet
available, making the efforts towards achieving an optimum mix is difficult. Each ingredient has a
significant role in the mix. Newspaper is most commonly used because it produces consistent
Jil Tushar Sheth, Saransh Joshi
Strategic Technologies of Complex
Environmental Issues-A Sustainable Approach - ISBN: 978-93-83083-85-5 86
results. When paper is mixed with cement, it creates a very good bond and the final product is both
lightweight and strong. Fibers contribute to sound insulation properties and help in crack control.
Portland cement is an integral component of the mix and acts as a binder.Cement reduces the
drying time and the effect of pulp shrinkage and increases the strength and dimensional stability.
However it adds weight to the mix and makes it more brittle. [1] Adding coir, sand, dirt or pumice
increases the volume and the mineral content. Sand adds thermal mass and makes the mix stronger
and impervious to water but results in heavier structure.
2. MATERIALS, PROPORTIONING AND MIX PREPARATION
A small scale work related to the material was carried out at CEPT University as part of the
summer school program. The following paragraphs illustrate the aspects of production, testing and
construction based on this work.
The main materials used for papercrete mix preparation were waste paper (newspaper), Portland
cement OPC-53 grade, Sand, Potable water and Soil.
Four types of mixes were prepared for the experiment. Mix proportions by volume in percentages
are indicated below:
1) 50% wet paper pulp/ 30% damp earth/ 10% dry sand/ 10% Portland cement
2) 60% wet paper pulp/ 20% damp earth/ 15% dry sand/ 15% Portland cement
3) 65% wet paper pulp/ 25% damp earth/ 10% Portland cement
4) 70% wet paper pulp/ 15% damp earth/ 15% Portland cement
Typically, earth may be sandy dirt, clay or clay-sand mix. It is desirable to have earth with high
clay content. The "wet paper pulp" was drained on a screen (can also be done by cloth) and further
water was added if required to adjust the workability. The first mix results in a hard and dense
material and the following mixes result in comparatively lighter and softer finished material.
The major steps for preparation of blocks and related equipment used are described below:
1. IS sieve 4.75mm was used to remove all coarse aggregate from the sand and soil by temping.
2. Shredded newspaper was wetted in water in the curing tank and a motor run machine called the
pulp beater machine was used to obtain wet paper pulp.
Paper Crete: A Sustainable Building Material
Strategic Technologies of Complex
Environmental Issues-A Sustainable Approach - ISBN: 978-93-83083-85-5 87
3. Next, the soil, sand, pulp and cement were mixed into a more uniform and consistent mass with
help of a cement mixer. The mixer machine was allowed to work for around 3 to 4 minutes to
obtain papercrete.
4. Wooden moulds were prepared in the experiment but acrylic or plastic sheets can also be used
for mould. The moulds were then greased with burnt oil or taping was done on the moulds
which may help in releasing the blocks quickly and easily.
5. The papercrete mix was then poured into moulds and compacted on a vibrating to remove
voids and achieve more density, resulting in stronger and more durable product. Temping bar
was also used for the same purpose.
6. The mix was then leveled to achieve satisfactory dimensions and finish.
7. After 40 hours, papercrete seemed to attain sufficient amount of strength after which the
moulds were released and casted blocks were allowed to sundry for further strength gain and
development of load carrying capacity.
Small structures in compression such as compound wall and arch were constructed as part of the
experiment. The masonry unit was bonded using mortar for the compound wall and fitted without
mortar using a key and hole mechanism inbuilt in the form of the block. Three types of mortar were
prepared for bonding: (a) Cement, sand and water (C:S-1:4) (b) Cement, sand, water and paper
pulp (C:S:P- 1:4:6) and (c) Cement, paper pulp and water (C:P:W-2:4:1). The last one was found to
be most appropriate and it was used for providing proper strength and bonding in the papercrete
masonry.
3. PROPERTIES OF PAPERCRETE
The above lab scale manufactured papercrete blocks were tested for key properties and
following values were obtained.
Compressive Strength
Compressive strength tests on 15 cm x 15 cm x 15 cm papercrete cubes revealed an average
compressive strength of 0.57 N/mm
2
after 3 days of cube preparation. Other research also suggests
similar results. [1, 5]. For more strength, higher grade of cement can be used.
Weight and Density
Density of the material increased with increase in the percentage of cement in the mixture and
reduced with increase in the amount of the paper in the mixture. Average weight of 8 cubes casted
Jil Tushar Sheth, Saransh Joshi
Strategic Technologies of Complex
Environmental Issues-A Sustainable Approach - ISBN: 978-93-83083-85-5 88
was observed to be 3.624 kg, thus block density was about 1.07 gm /cc. This is therefore
lightweight in comparison to standard concrete or brick masonry units.
Shrinkage
Shrinkage measured was between 8-9% in each block.
Water absorption
Water absorption of the blocks was about 30% in all cases.
Drying time
40 hours at least are needed for drying of papercrete before it can be demolded. After this it should
be sundried for 4 days before usage for better strength. Or it can be placed in oven at nearly 70 °C
for 40 hours after casting. Putting it at higher temperature than this can result into segregation of
material.
Tests for other properties such as 7 day and 28 day compressive strength, thermal resistance, sound
insulation, behavior under fire etc. are under progress.
4. APPLICATIONS
As part of the summer school work, a group of
30 students conceived and designed various
structures like interlocking arch (180 cm
radius) which did not need any binder for
joinery (Refer fig). Other structures
constructed on campus included seating, a
funicular shed and a compound wall. Apart
from this, papercrete can be used for plastering
and can be given any form, be it panels or
curved elements. Literature illustrates its uses
for partition walls, and façade material where
benefit of dead load reduction of the structure is
obtained. It can be used in interiors as it
provides aesthetics and opportunity for diverse designs. High rise buildings in seismic zone can use
papercrete as it is less catastrophic then other materials like concrete but due to limitations in some
other properties such as behavior towards fire, durability concerns, biodegradability etc. it requires
a significant amount of research for justifying its applications.Houses of paper may be trend of
future.[4]
Figure 1 :papercrete interlocking arch made by
jil,dhruv,shivam,aakansha and devisha as a group.
Paper Crete: A Sustainable Building Material
Strategic Technologies of Complex
Environmental Issues-A Sustainable Approach - ISBN: 978-93-83083-85-5 89
5. ADVANTAGES AND DISADVANTAGES OF PAPERCRETE
Papercrete can be produced by harnessing solar energy. The only power needed is for the purpose
of mixing. Papercrete is far lighter in weight and has remarkable insulating qualities, unlike
concrete which is relatively heavy. It can be easily shaped when cured and dried. The most
important benefit of papercrete is the reduction of cement in the mix. Carbon footprint during
production, the total cost and weight are reduced, resulting in an eco-friendly and lightweight
material. Paper fibers result in excellent heat and sound insulating properties. Papercrete
incentivizes the recycling of waste paper, especially in communities with no recycling services.
Papercrete is viable option for low cost housing and temporary shelters and offices. Crises of
building materials lead to high demand and need for recycling industrial waste or finding
alternative source. Wastepaper helps in low- cost, eco friendly and therefore, sustainable design. In
India’s context only a fraction of paper is recycled annually. This means that the rest is still
disposed off, mostly ending up in landfills for slow degradation and capacity consumption of
dumpsites. Conservatively speaking, it takes about 15 trees to make 1 ton of paper.[2] As it is
recycled material, there is a benefit in embodied energy due to reutilization. It has good thermal
and sound insulation properties.
The material has certain limitations in its application.[3] Apart from the fact that the material is still
to be recognized and researched, there are also major obvious shortfalls in the materials mechanical
and chemical properties. Lack of literature, official data or guidelines on its preparation, structural
behavior or long term viability is one of the constraints for commercial usage of the material.
Papercrete is a brittle material. It expands and contracts frequently leading to cracks, bulging and
buckling and it has very low tensile strength. It is difficult to exercise quality control of the mix
batches and obtain smooth surface. There is also a major issues of dimensional stability. Also, it is
not waterproof and flameproof and this is not desirable for building applications. The production of
papercrete units uses a large quantum of water. Durability is another major issue owing to the
tendency of paper to degrage due to thermal, biological and chemical action.
Certain limitations in the properties can be overcome by below measures:
1. Modification of mix proportions can help achieve optimum properties.
2. Addition of reinforcement like coconut fiber (5%-10%) or fly ash can be done to improve
compressive strength of papercrete.
3. Color and texture can be added to papercrete for better aesthetics and design versatility.
4. Addition of silicon, concrete sealer or epoxy compound can help in waterproofing of
papercrete.
Jil Tushar Sheth, Saransh Joshi
Strategic Technologies of Complex
Environmental Issues-A Sustainable Approach - ISBN: 978-93-83083-85-5 90
5. Admixtures can also be added to improve setting and bonding properties.
6. Higher strength can be obtained by using higher grade of cement.
7. Papercrete made with certain mixes are resistant to fire, fungi, and pests to a larger extent.
8. Papercrete blocks made with a sufficient quantity of Portland cement and sand have improved
fire resistance.
6. CONCLUSION
This study was conducted with an aim to learn the small scale preparation of papercrete blocks, its
design and construction skills and also had a focus on the assessment of the properties of this
building blocks. The study recognized papercrete as a sustainable building material and
emphasized on more research towards its performance parameters. The manufacturing, processing
and construction techniques are still not developed enough to facilitate its use and this requires
extensive amount of research. Papercrete can be developed as a material which is suitable for low
cost housing and temporary shelters and offices and can help reduce carbon footprint. It is thus
evident that it can be looked upon as a sustainable building material and has a promising future.
REFERENCES
[1] Titzman Clincton L.,http://www.scribd.com/doc/87323737/Titzman-Thesis, Analysis of low cost
building material for the mixalco process, December 2006
[2] Bhooma Nepal and Vanita Aggrawal, ”Papercrete: A study on green structural material,International
journal of applied engineering research”, March 2014 Vol9
[3] Information on http://www.greenhomebuilding.com/papercrete.htm
[4] Information on http://news.nationalgeographic.com/news/2001/06/0612_paperhouses.html
[5] Information on http://papercrete.wordpress.com/2011/04/20/experiment-10/
ACKNOWLEDGEMENT
We are thankful to our faculty, Mr. Nikunj Vakani and Mr. Pranav Gajjar for guiding us through
the papercrete workshop. We also thank the lab assistants at the University for their support. We
acknowledge the efforts of our team members in this workshop. We are grateful to Prof. Anal
Sheth for her inputs and motivation in publishing this kind of work.