Green Solution

NARIMAN KHALIL, Ph.D. Civil Engineering Dept.

UNIVERSITY OF BALAMAND

“State of the global system, which includes environmental, social and economic subsystems, in which the

needs of the present are met without compromising the ability

of future generations to meet their own needs*

Brundtland Commission 1987

Koji Sakai, Prof. of Kagawa University Chair of ISO/TC71/SC8, fib SAG 8, JCI

Concrete is made from the most abundant substances on earth: aggregate, cement, water, others.

It is the second most consumed substance on Earth after water .

Over 25 billion tons of concrete are used worldwide each year.

In Europe they produce an equivalent of one cubic meter of concrete per inhabitant each year, and this number continues to increase.

Because of the sheer volume of concrete used (and the associated resources and energy used to make it), WISE USE of this material can make significant contribution to the achievement of sustainable development. This includes looking at the entire life cycle of a concrete structure to focus on areas where changes will make the most impact.

∎ Inadequate safety of concrete structures to unforeseen external forces

How to set safety factors of materials, external forces & others in the Design Stage?

∎ Enormous consumption of Natural Resources

How to reduce it? ∎ Generation of a Large Amount of CO2 in

cement /steel production and construction works. How to reduce it?

Innovative design can reduce the total quantity of concrete used and reduce the amount of cement used/m3 of concrete

A new source of raw material that local batching plants can use, that is the Recycled Concrete Aggregate (RCA).

Alluvial: Rivers, Lakes, Ponds

Hard Rock: Quarries

In a country like Lebanon with limited natural resources, the use of RCA holds special importance.

Studies showed that quarries can annually reduce an estimated surrounding land value by 16 to 71%.

The estimated number of quarries in Lebanon is about one thousand.

Sixteen permissible quarry locations (Ministry of Environment)

Muhafaza Distribution of

coarse aggregate quarries

Bekaa 32

Mount Liban 8

North 3

South 1

Taxes introduced on the use of virgin aggregates. France Total Area : 673,801 km2

Vs. Lebanon Area =10,452 km2

42 universities, laboratories, research centers, industrial institutions Duration of The project: 4 years starting 2012 Fund: 5 Million Euro

Recycled concrete is sourced from:

Demolition and repair work of concrete structures

Recycled concrete is sourced from:

Sidewalks, Pavements

Recycled concrete is sourced from:

WAR

Concrete 58.1%

* Chehab & Srour, AUB

Concrete,58.1%

Steel, 3.3%

Hourdis,

6.6%

Masonry,20.4%

Aluminum/

Glass, 0.1% Tiles, 8.6%

Wood, 0.1%

Ceramics, 2.8%

Other, 0.1%

Percentage Composition of Building Material in Lebanon (by mass)

Material Quantity (Tons)

Destination

Concrete 528,000 Dump

Hourdis 60,000 Dump

Masonry 186,000 Dump

Total 910,000

85% Cementitious Material

* Chehab & Srour, AUB

In Place

Fixed Plants

Aggregate base course (road base)

Recycled concrete and recycled asphalt is frequently used as the foundation for roads and highway pavement.

The aggregate base course is placed upon the subgrade directly underneath the paved surface and is a highly effective structural foundation for paving

Soil Stabilization

Recycled aggregates can be mixed in with lower quality subgrade material to strengthen the load bearing capacity of the subgrade. The blend of recycled aggregate alters the water permeability of the subgrade and improves the stability of the soil.

Pipe bedding

As an alternative to virgin aggregate, recycled concrete functions appropriately as a stable foundation for underground utilities.

Others

Production of New Concrete Researchers are examining the possibility

of using recycled concrete as coarse aggregates in producing structural concrete.

The effect of different percentages of RCA on the mechanical properties of concrete is investigated

Also the flexural behavior of RAC Beams

Different percentages of RCA were considered:

0%, 30%, 50%, 75%, 100%

Recycled concrete from demolition projects can result in considerable savings because it saves the cost of hauling broken concrete to landfills and eliminates disposal costs.

RCA has economic feasibility merits in small to medium sized projects.

Savings can be significant when high dumping fees and/or imposed taxes are implemented.

The benefits of utilizing Recycled Concrete is an important consideration for construction project planning.

Recycled Aggregate conserves landfill space by eliminating waste disposal to alternatively recycled usable materials.

The recycling process eliminates the negative environmental impact of the virgin aggregate extraction process while conserving virgin materials.

N. Khalil

Thank

you