Access over 20 million homework & study documents

Use of RECYCLED AGGREGATES In CONCRETE- A Paradigm Shift

Content type
User Generated
Type
Study Guide
Rating
Showing Page:
1/5
Use of RECYCLED AGGREGATES In CONCRETE- A Paradigm Shift
S. K. Singh, Scientist, Structural Engineering Division, Central Building Research Institute, Roorkee and
P. C. Sharma, Head ( Retd.), Material Sciences, SERC,(G) and Editor New Building Materials &
Construction World, New Delhi, Chairman, Indian Concrete Instt. UP Gaziabad Centre.
One of the major challenges of our present society is the protection of environment. Some of the important elements
in this respect are the reduction of the consumption of energy and natural raw materials and consumption of waste
materials. These topics are getting considerable attention under sustainable development nowadays. The use of
recycled aggregates from construction and demolition wastes is showing prospective application in construction as
alternative to primary (natural) aggregates. It conserves natural resources and reduces the space required for the
landfill disposal.
This paper presents the experimental results of recycled coarse aggregate concrete and results are compared with
the natural crushed aggregate concrete. The fine aggregate used in the concrete, i.e. recycled and conventional is
100 percent natural. The recycled aggregate are collected from four sources all demolished structures. For both types
of concrete i.e. M-20 and M-25, w/c ratio, maximum size of aggregate and mix proportion are kept constant.
The development of compressive strength of recycled aggregate concrete at the age of 1,3,7,14,28, 56, and 90 days;
the development of tensile & flexural strength at the age of 1,3,7,14 and static modulus of elasticity at the age of 28
days are investigated. The results shows the compressive, tensile and flexural strengths of recycled aggregate are

Sign up to view the full document!

lock_open Sign Up
Showing Page:
2/5
on average 85% to 95% of the natural aggregate concrete. The durability parameters are also investigated for
recycled aggregate concrete and are found to be in good agreement with BIS specifications.
Introduction
Any construction activity requires several materials such as concrete, steel, brick, stone, glass, clay, mud, wood, and
so on. However, the cement concrete remains the main construction material used in construction industries. For its
suitability and adaptability with respect to the changing environment, the concrete must be such that it can conserve
resources, protect the environment, economize and lead to proper utilization of energy. To achieve this, major
emphasis must be laid on the use of wastes and byproducts in cement and concrete used for new constructions. The
utilization of recycled aggregate is particularly very promising as 75 per cent of concrete is made of aggregates. In
that case, the aggregates considered are slag, power plant wastes, recycled concrete, mining and quarrying wastes,
waste glass, incinerator residue, red mud, burnt clay, sawdust, combustor ash and foundry sand. The enormous
quantities of demolished concrete are available at various construction sites, which are now posing a serious problem
of disposal in urban areas. This can easily be recycled as aggregate and used in concrete. Research & Development
activities have been taken up all over the world for proving its feasibility, economic viability and cost effectiveness.
An investigation conducted by the environmental resources ltd. (1979) for European Environmental commission
(EEC) envisages that there will be enormous increase in the available quantities of construction and demolition
concrete waste from 55 million tons in 1980 to 302 million tons by the year 2020 in the EEC member countries. As
a whole, the safety and environment regulations are becoming stringent, demand for improvement in techniques &
efficiency of the past demolition methods is getting pronounced. Special rules and regulations concerning the
demolition have already been introduced in several countries like U.K., Holland and Japan.
The main reasons for increase of volume of demolition concrete / masonry waste are as follows:-
i. Many old buildings, concrete pavements, bridges and other structures have overcome their age and limit of
use due to structural deterioration beyond repairs and need to be demolished;
ii. The structures, even adequate to use are under demolition because they are not serving the needs in present
scenario;
iii. New construction for better economic growth;
iv. Structures are turned into debris resulting from natural disasters like earthquake, cyclone and floods etc.
v. Creation of building waste resulting from manmade disaster/war.
In study conducted by authors for RCC buildings, the approximate percentage of various construction materials in
demolition waste is presented in Fig. 1. This may vary depending upon the type of structure.
In many densely populated countries of Europe, where disposal of debris problem is becoming more and more
difficult, the recycling of demolition waste has already been started. As per the survey conducted by European
Demolition Association (EDA) in 1992, the several recycling plants were operational in European countries such as
60 in Belgium, 50 in France, 70 in the Netherlands, 120 in United Kingdom, 220 in Germany, 20 in Denmark and 43
in Italy. The recycling of construction & demolition waste becomes easy & economical, wherever combined project
involving demolition and new construction are taken up simultaneously. The possible uses of construction and
demolition wastes are given in Table 1.
Recycling and Reuse of Construction & Demolition Wastes in Concrete

Sign up to view the full document!

lock_open Sign Up
Showing Page:
3/5

Sign up to view the full document!

lock_open Sign Up
End of Preview - Want to read all 5 pages?
Access Now
Unformatted Attachment Preview
Use of RECYCLED AGGREGATES In CONCRETE- A Paradigm Shift S. K. Singh, Scientist, Structural Engineering Division, Central Building Research Institute, Roorkee and P. C. Sharma, Head ( Retd.), Material Sciences, SERC,(G) and Editor New Building Materials & Construction World, New Delhi, Chairman, Indian Concrete Instt. UP Gaziabad Centre. One of the major challenges of our present society is the protection of environment. Some of the important elements in this respect are the reduction of the consumption of energy and natural raw materials and consumption of waste materials. These topics are getting considerable attention under sustainable development nowadays. The use of recycled aggregates from construction and demolition wastes is showing prospective application in construction as alternative to primary (natural) aggregates. It conserves natural resources and reduces the space required for the landfill disposal. This paper presents the experimental results of recycled coarse aggregate concrete and results are compared with the natural crushed aggregate concrete. The fine aggregate used in the concrete, i.e. recycled and conventional is 100 percent natural. The recycled aggregate are collected from four sources all demolished structures. For both types of concrete i.e. M-20 and M-25, w/c ratio, maximum size of aggregate and mix proportion are kept constant. The development of compressive strength of recycled aggregate concrete at the age of 1,3,7,14,28, 56, and 90 day ...
Purchase document to see full attachment
User generated content is uploaded by users for the purposes of learning and should be used following Studypool's honor code & terms of service.

Anonymous
Really helpful material, saved me a great deal of time.

Studypool
4.7
Trustpilot
4.5
Sitejabber
4.4