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DEPARTMENT OF CIVIL ENGINEERING

“Advanced Research in Recycled Aggregate concrete”

18th March 2017

Presented By:

Dr. D. N. Parikh

Lecturer, BPTI, Bhavnagar

AT

GMIT, Bhavnagar

Principal H.O.D.

Dr. H.M. Nimbark Prof. K.V. Purohit

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Content

(1) Acknowledgement 3

(2) Information 4

(3) Topic of Expert Lecture 4

(4) What we learnt? 5

(5) Valedictory 9

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ACKNOWLEDGEMENT

We the students of civil engineering, are really thankful to our

Principal and the Head of the Department of civil branch of GMIT,

Dr. H.M. Nimbark sir and Prof. Kishan Purohit respectively, for the

knowledge sharing session of “Recycled Aggregate Concrete”

Lecture GMIT, Bhavnagar.

We are also thankful to Dr. D.N. Parikh Sir, Lecturer at BPTI,

Bhavnagar to share the valuable knowledge to us. It will be very

helpful to us in future whenever we start our professional career or at

post graduation programme or in final year project also.

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General Information regarding expert lecture

The department of Civil Engineering has organized an Expert

Lecture on “Advanced Research in Recycled Aggregate Concrete” on

18th March 2017 at GMIT, Bhavnagar.

Recycled aggregates are the materials for the future.

Urbanization growth rate in India is very high due to industrialization.

Growth rate of India is reaching 9% of GDP. Rapid infrastructure

development requires a large quantity of construction materials, land

requirements & the site. For large construction, concrete is preferred

as it has longer life, low maintenance cost & better performance. For

achieving GDP rate, smaller structures are demolished & new towers

are constructed. Protection of environment is a basic factor which is

directly connected with the survival of the human race. Parameters

like environmental consciousness, protection of natural resources,

sustainable development, play an important role in modern

requirements of construction works. Due to modernization,

demolished materials are dumped on land & not used for any purpose.

Topic of Expert Lecture

Our main purpose for this expert lecture is to be familiar with

industrial environment and to get research knowledge of advanced

concrete technology and use of its various concrete in field. Also in

4th semester subject like concrete technology requires knowledge

about how different ingredients, research are shared in the field, so it

is very much convenient to see the research and components in real

time work environment.

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What We Learnt

Concrete is the premier construction material across the world

and the most widely used in all types of civil engineering works,

including infrastructure, low and high-rise buildings, defense

installations, environment protection and local/domestic

developments. Concrete is a manufactured product, essentially

consisting of cement, aggregates, water and admixture(s). Among

these, aggregates, i.e. inert granular materials such as sand, crushed

stone or gravel form the major part. Traditionally aggregates have

been readily available at economic price. However, in recent years the

wisdom of our continued wholesale extraction and use of aggregates

from natural resources has been questioned at an international level.

This is mainly because of the depletion of quality primary aggregates

and greater awareness of environmental protection. In light of this, the

availability of natural resources to future generations has also been

realized.

Waste arising from Construction and Demolition constitutes one

of the largest waste streams within the EU, Asian and many other

countries. For example, it is estimated that core waste (described as

those types of materials which are obtained from demolished building

or civil engineering infrastructure) amounts to around 180 million

tonnes per year or 480kg/person/yr in the EU. This ranges from over

700 kg/person/yr in Germany and the Netherlands to under 200 in

Sweden, Greece and Ireland. The estimates for the UK are 30million

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tonnes/yr and just over 500 kg/person/yr respectively, putting the UK

in second place behind Germany.

This is in addition to large quantities that are dumped illegally.

Thus, construction demolition waste has become a global concern that

requires sustainable solution.

The compressive strength seems to increase slightly with the

addition of RCA. This could be due to the higher absorption capacity

of the recycled aggregate. When the water is absorbed by aggregate,

more space left by the water being absorbed can be occupied by

aggregates in a unit volume. Hence the density of recycled concrete is

lower.

It is observed from the fractured surface of RCA with high

amount of recycled coarse aggregates, the failure is not only through

the interface but also through the recycled aggregates. The split

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tensile strength of RCA reduces with the increase in amount of RCA.

The split tensile strength of recycled concrete with replacement of

50% of RCA was higher than the split tensile strength of the control

concrete.

The split tensile strength of recycled concrete with replacement

of 100% RCA was less than split tensile strength of control concrete.

As with the compressive strength, the split tensile strength of recycled

concrete is higher during early stage but it gains strength at a slower

rate during later stages. The splitting tensile strength gives more

uniform results as compared to compressive strength.

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It can be concluded that RCA upto 50% is satisfactory to use. It

will also be economical with the reduce in transportation cost of

dumping the aggregates. Primary reason of strength reduction may be

the adhered mortar to the RCA and other non-aggregate material. This

can be corrected by using proper cleaning techniques and casting

methods under highly skilled supervision.

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Valedictory

At the end of the expert lecture, few question were asked from the

faculty as well as among from the students and all the students were

found very interesting and interacting session. At the valedictory

session, 4th Semster civil student Chirag Chavda had felicitated Dr. D.

N. Parikh sir with a memento.

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PREPARED BY Joshi Jay

Kishan Kabir

Trivedi Malay

ParMar Kishan

Yash Kajawadra