Sustainable Construction
Scarcity of land and other resources is a reality, particularly in a small country like
Singapore. It is therefore critical for us to make the best use of limited resources, and
at the same time be prepared to tackle any challenges that may arise in the future.
Through Sustainable Construction, we can do our part to optimise the use of natural
resources and pursue the greater use of recycled materials. Besides reducing our
dependence on natural building materials, this will also help to safeguard our quality of
life and make provision for the continuing growth of our built environment.
Picture taken from http://www.ci.berkeley.ca.us/ContentDisplay.aspx?id=23798

Sustainable construction refers to the adoption of building designs, construction
methods and materials that are environmentally friendly.

It also means using materials and resources that have sustainable supplies and
are readily available from many sources.

Sustainable construction will optimize the use of natural resources via recycling
and reuse of materials.

Steel, other metals, glass and prefabricated parts using combinations of these, as
well as recyclable substitutes for concrete are examples of sustainable materials
and products.
Sustainable building materials
Steel

Steel is an excellent reusable material.

Steel can be recycled repeatedly without any degradation in terms of properties or
performance in quality.

Steel construction generates very little waste, with the byproducts of steel
production widely reused by the construction industry.

Any waste generated during manufacture is recycled. There is virtually no waste
from steel products on the construction site.
Collection of scrap metal for recycling (Courtesy of Building and Construction
Authority of Singapore)
Benefits

Strong and light
Steel has one of the highest strength to weight ratio of any construction material. Steel
framing can weigh only one-third as much as traditional construction materials. When
connected by fasteners, a steel frame is stronger than traditional systems. This
provides savings in the foundation and to the amount of cranage needed on site.

Labour Saving
Lightweight steel framing systems are generally simpler to erect than conventional
systems. Once the workers are experienced with steel, labour time and costs will be
reduced considerably.

Design Flexibility
Because of its strength, steel can span greater distances offering larger open spaces
and increased design flexibility without requiring intermediate columns or load bearing
walls.

Better Construction Quality
Steel does not suffer from creep or shrinkage and when properly protected, does not
rot or decay.

Speed
Steel buildings can be erected in much shorter time as compared to concrete buildings.
Time saving in the construction period can be up to 40%.

Minimal disruption
Steel construction can dramatically reduce the impact of building activities on the
surrounding area. This is particularly important in city locations or sites close to
residential areas.
Steel construction minimises noise and dust, shortens the construction period and
reduces waste generation.

Environmentally Friendly
Steel offers a clean, efficient and rapid construction method, which reduces the impact
of building activities on the environment.
All steel products are 100% recyclable. Today, around 40% of steel is produced from
recycled materials.
Recycled building materials
To enhance sustainability in the construction industry, wastes can be turned into
resources to reduce disposal problems in Singapore.
A few types of waste are being studied, such as:

Incinerator ashes from domestic refuse

Spent copper slag fines which are residue from sand blasting

Waste concrete from construction, renovation and demolition (CRD) of old
buildings
Copper Slag

Copper slag is a by-product formed during the copper smelting process.

The application of copper slag in non-structural components like partition walls and
road has proven its efficiency as a sand replacement.

For structural usage, the use of copper slag as partial replacement of sand in
concrete is allowed for up to 10% by mass.
Production of copper slag (picture taken from
http://www.bca.gov.sg/SustainableConstruction/sc_copper_slag.html)
Copper slag (picture taken from http://www.free-press-release.com/news/200905/1241641856.html)
Steel slag

Steel slag is a by-product formed during the steel-making process.

The amount of steel slag available for reuse is estimated to be 0.1 million tons per
year.
Conventional granite and steel slag (courtesy of Building and Construction Authority of Singapore)
Construction and Demolition Waste

Construction and demolition (C&D) waste is the material resulting from the
construction, alteration or demolition of buildings and other structures.

It consists of a mixture of hardcore (concrete, masonry, bricks, tiles), reinforcement
bars, dry walls, wood, plastic, glass, scrap iron and other metals etc.

C&D waste can be channeled to appropriate recycling facilities for processing into
useable products.

Materials such as reinforcement bars and scrap metals have traditionally enjoyed a
high recycling rate due to their high residual economic value.

In recent times, more of the various constituents of C&D waste have attracted
viable recycling efforts focused on creating new value for C&D waste. Examples
include recycled concrete aggregate and wood waste (to be discussed in the
following sections)

The average amount of C&D waste available for reuse is estimated to be 2 million
tons per year.
C&D waste at demolition site (courtesy of Building and Construction Authority of Singapore)
Recycled Concrete Aggregates

Recycled concrete aggregates (RCA) is derived mainly from the crushed concrete
from demolition waste.

70% or more of demolition waste is made up of crushed concrete.
Typical process to reclaim RCA (courtesy of Building and Construction Authority of Singapore)
Wood Waste
Wood waste at demolition site (taken from
www.musserlumber.com/bio-mass.htm)

Wood waste constitutes about 3% to 30%
of construction and demolition (C&D)
waste.

The quantity of waste generated per year
is about 0.1 million tons.

With technological means, wood waste
can be converted to wood-based products
with enhanced properties.

Compressed wood products have the
added benefit of being pest-free, fire
retardant,
denser,
stronger,
more
consistent in texture and color, and lower
in moisture content as compared to natural
wood.
Videos
Sustainable Built Environment
http://www.youtube.com/watch?v=fRIISpinTbo
Reused & Recycled Materials in Concrete Floors
http://www.youtube.com/watch?v=8k5cpHjyWK0
Recycled houses
http://www.youtube.com/watch?v=a9JkPk0CIo4
DIY Cardboard Furniture Reuse Design
http://www.youtube.com/watch?v=cOa1kHEiIpg&feature=related
Further reading:
7 of the coolest and greenest recycled buildings
http://www.greenopia.com/USA/news/15197/3-20-2009/Seven-of-the-CoolestGreenest-Recycled-Buildings