13. Dr. Wail N. Al-Rifaie

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Modern Housing System using Ferrocement As Sustainable

Construction Materials

By

Wail Nourildean Al-Rifaie

Professor of Civil Engineering

Professor Emeritus, University of Tikrit, Iraq.

Summary

The use of ferrocement in pre-fabricated buildings provides many advantages in terms oflightness of weight (since its thickness is usually between10 and 50mm), ease ofhandling, low labour cost in its production and a durable material requiring little

maintenance. This would further lead to an eco-friendly low cost housing without anyloss of structural integrity. Saving in cost is one of the several reasons for the popularity

of ferrocement. It is recognized that the economics of ferrocement is dependent onseveral factors such as costs of raw materials and labour, and the relative cost ofcompetitive materials. In this article a structural system for ferrocement building based

on generic services facilities is introduced.

IntroductionThere are more than 80 developing countries in the world suffering from housing

shortage, resulting from population growth. In rural areas, houses should be built aseconomical as possible and at the same time should be durable and functional. Hence, It

has become necessary to seek for structural building elements, which have the structuralphenomena of prefabricated elements in terms of ease of handling, light, minimum

maintenance and low cost. It is with these in mind, elements of a structural system aremade from Ferrocement.

Ferrocement has been developed mainly during the past thirty years and yet has reached avery advanced stage in technique and design. A considerable amount of laboratory

testing research and prototype constructions have been completed at the Building andConstruction Engineering Department of University of Technology, Iraq for the

production of ferrocement members that would be used in the roof /floor/wall ofbuilding/housing.

Ferrocement has a very high tensile strength to weight ratio and superior crackingbehaviour in comparison to reinforced concrete. Hence, Ferrocement is an attractive

material for construction of shell, folded plate, ribbed slab and housing components. The

growing need for eco-housing is much-discussed subject. The great demands of electricpower due to heating and air-conditioning systems require control to make maximumreduction of the electrical energy. Prefabricated ferrocement cavity walls present a series

of possibilities for the solution of building construction at maximum reduction of theelectrical energy.

Ferrocement, 10-50 mm thick, is a type of thin reinforced concrete with great potential,made of cementsand mortar and reinforced with layers of fine wire meshes with

skeletal reinforcement. Ferrocement is an excellent construction material due to its


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mechanical properties, and low cost, and it is considered to possess a high crackingstrength.

Ferrocement is a suitable construction technology for the following reasons:

1. Ferrocement differs from conventional reinforced concrete in that there is a higherratio of steel to cement mortar. By altering the mortar/steel ratio the ferrocementmaterial exhibits properties superior to either steel or cement mortar separately.

2. Ferrocement resistance is given by the geometrically shape parts.3. The constituent materials of ferrocement are easily available and are quite

inexpensive, labour intensity and semi-skilled labour requirements makeferrocement the most promising alternative materials for housing.

4. The fabrication technique of ferrocement is quite easy and common.5. Heavy plants and machinery are not required in the ferrocement construction.6.

In case of damage, it can be repaired easily.

Ferrocement as Sustainable Construction Materials:The low material cost, labor intensity and semi-skilled labor requirements makeferrocement is the most promising alternative materials for housing. The constituent

materials of ferrocement are easily available and are quite inexpensive. The fabricationtechnique of ferrocement is quite easy and common people could be trained in a short

time to learn the skill. Advantages of ferrocement as a construction material may besummarized as follow:

1. Very high quality control.2. Pre-Fabricated products.3. Easy production and installation.4. Shading devices to provide shading and day lighting to the building (use light

weight and low cost environmental element).

5. Fast construction.6. Manpower can be easily trained at site.7. Improved structural performance.8. Cost reduction, 15-50% cheaper than conventional techniques.9. Less maintenance.10.Reduction in dead weight, 50-75% lighter than conventional techniques.

The adoption of ferrocement as an appropriate particularly suited for houses because of

the following:1. Basic raw materials are available.2. The skills required for ferrocement construction are easily acquired.3. Lower construction cost compared to traditional construction.4. Easy to construct.5. Lower maintenance cost than traditional material.


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a. Impact Resistance of Ferrocement: Ferrocement is very adequate to resist the

impact, due to its higher abilityof absorbing impact energy ascompared with the conventional

reinforced concrete, and thedamage is localized at the impact

zone. Tests were carried out atthe laboratory of Civil

Engineering Department at the University of Nottingham, U.K.

b. Rehabilitation/or Strengthening Technique by

Ferrocement: It is concluded that strengthening of

reinforced concrete element by using ferrocementtechnique is very effective in increasing thecracking, ultimate loads and increasing the impact

resistance. Tests were carried out at the NationalCenter of Construction Laboratory, Baghdad, Iraq.

c. Fire Resistance:The ferrocementbuilding components

can withstand directfire with a

temperature values upto 756o

C for a period

of 2hours with nosegregation in the surface of the elements facing the fire. Tests were carried out at

ferrocement victory, Baghdad, Iraq.

d) Blast protection:Blast protection for structures under direct or indirect threat fromexplosive hazards often requires retrofit solutions with minimal or temporary

environmental impact whilst providing structural shielding from shock waves andshrapnel and spall fragments. These situations include structures under direct assault or in

post-conflict areas where unexploded ordinance pose a continuing hazard.

Ferrocement

panelling provides a modular and effective passive solution. Theincorporation of continuous steel wire reinforcement lends a pseudo-ductility underimpact loading which boost structural integrity compared with conventional reinforced

concrete and concentrates damage at the impact zone. Splinter penetration is minimalthrough the thickness of such slabs and short range proving tests with 7.62mm rounds

have demonstrated excellent damage tolerance for relatively low density installations.


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Housing SystemA structural system (Copyright The University of Nottingham, U.K.) for ferrocement

construction based on generic services facilities is introduced.The construction concepts for low cost, low impact housing and shelters as shown in

Figure 1 lend themselves readily to rapid delivery and assembly of flexibleaccommodation where designs can be adapted to meet local requirements for both

structural performance and thermal comfort as shown in the figure. The structural part ofhouse consists of three basic components; the base, walls, and roof. An integral framing

concept as shown in plate 1 allows for overall above-ground structural integrity whichconsiderably exceeds that of traditional methods and this minimizes the need for ground

works in all. The membrane construction also enables new concepts in passivedowndraught cooling to be explored where airways are incorporated within structural

features as wall cavities.

Base Walls during fixingPlate (1)

Rear panel after complete testing,only full penetration of both sandand fill done when SPA and

concentrated fire was used.

120 rounds fired across all panels,filled and unfilled.Front panel, concentration of

rounds onto the filled panels, nocracking to the front or rear

panels


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Figure (1)

Potential applications of the system include sustainable solutions for disaster relief and

secure accommodation. The major advantage of a ferrocement construction system overcurrent construction methods is mainly due to the reduction in structural dead load.

Building system must not only cope withstrengths and flexibility requirements, but the

insulation value is of high importance. In summerheat must be kept outside as much as possible.

The structural system for ferrocementconstruction based on generic services facilities

and insulating these structures involves the

application of insulation material by means of

cavity wall construction which consists of twoleaves (sides) of ferrocement separated by a wide

space and insulation material is used through acavity wall and filling the air space with a porous

material. Test was carried out on a ferrocementcavity wall panel with insulation panel placed

between the two leaves of the wall panel asshown in Plate (2). The obtained results showed Plate (2)

that cavity wall construction consists of two leaves (sides) of ferrocement, separated byair space and the insulation panel positioned as shown in the figure gives a very good

solution for insulation as shown in Plate (3), (air is still the actual insulator), consequentlyreducing the demand to electrical energy. Cavity wall insulation may also be used to


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reduce heating/or cooling losses. In addition the space between the insulation andferrocement panels may be filled with porous materials.

Front face Rear face

Plate 3(a) Heating measurements of ferrocement panel representing the wall.

Lower face Upper face

Plate 3(b) Heating measurements of ferrocement panel representing the roof.


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The following photos show some of the projects executed in Iraq.

Two-bedroom house constructedin the year 2000

Two-bedroom house constructed in 2001 Warehouse.

Two-bedroom house

Kiosk that was constructed for theInternational Baghdad Exhibition in the

year 2000.

Fifty three bus stops constructed in thecentre of Baghdad


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Studio Benches

Mosque under construction

Building constructed in Feb. 2011 using the modern housing system.


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18. Al-Rifaie, W.N.,The Behaviour of Two-Way Ferrocement Slabs under Impact

Loads. Proceedings of the Sixth Arab Conference in Structural Engineering,1995.

19. Al-Rifaie, W.N. Ferrocement Wall: Penetration Testing. The Eighth International

Symposium and Workshop on Ferrocement and Thin Reinforced Cement Composites, 6-8 February, 2006, Bangkok, Thailand.20. Zaki, M. and Al-Rifaie, W.N. ,Design Of Ferrocement in Flexure. , Journal of

Engineering and Technology, University Of Technology, Vol 18, No. 4, Iraq 1999.21. Al-Rifaie, W.N.and Mahmood, N.S,Finite Element Method for Non-Linear Analysis

of Ferrocement Slabs and Box-Beams. Proceedings of the Seventh InternationalSymposium on Ferrocement and Thin Reinforced Cement Composites (FERRO-7),

Singapore, 2001.22. Al-Rifaie, W.N.and Mahmood, N.S,Computational Model for Non-linear Analysis

of Ferrocement Shells Using F.E.M. Journal of Ferrocement, Vol. 30, No. 1, January2000.

23. Al-Rifaie, W.N.and Majeed, A., Structural Behaviour of Thin FerrocementOne-Way Bending Elements. Journal of Ferrocement, Volume 24, No. 2, 1994.

24. Al-Rifaie, W.N.and Abdul-Aziz, A.,Thin Ferrocement Bearing Walls. Journal ofFerrocement, Volume 25, No.3, 1995.

25. Al-Rifaie, W.N.and Al-Hmedawi, A., Structural Behaviour of Ferrocement ShellsRoofs. Journal of Ferrocement, Vol. 30, No. 1, Jan. 2000.

26. Al-Rifaie, W.N.and Mnasrah, A.Connection for Segmental FerrocementSemi-Cylindrical Shells as a Roofing System. Journal of Ferrocement, Vol. 31,

No.1, January 2001.27. Al-Rifaie, W.N.and Kalaf, S.Experimental Investigation of Long-Span Roofing

System. Proceedings of the Seventh International Symposium on Ferrocement and ThinReinforced Cement Composites (FERRO-7), Singapore, 2001.

13. Dr. Wail N. Al-Rifaie

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