Summary and Recommendations[edit | edit source]
I. Summary and Recommendations[edit | edit source]
Ferrocement is a highly versatile form of reinforced concrete made of wire mesh, sand, water, and cement, which possesses unique qualities of strength and serviceability. It can be constructed with a minimum of skilled labor and utilizes readily available materials. Proven suitable for boatbuilding, it has many other tested or potential applications in agriculture, industry, and housing.
Ferrocement is particularly suited to developing countries for the following reasons:
· Its basic raw materials are available in most countries.
· It can be fabricated into almost any shape to meet the needs of the user; traditional designs can be reproduced and often improved. Properly fabricated, it is more durable than most woods and much cheaper than imported steel, and it can be used as a substitute for these materials in many applications.
· The skills for ferrocement construction are quickly acquired, and include many skills traditional in developing countries. Ferrocement construction does not need heavy plant or machinery; it is labor-intensive. Except for sophisticated and highly stressed designs, as those for deep-water vessels, a trained supervisor can achieve the requisite amount of quality control using fairly unskilled labor for the fabrication.
The following specific recommendations are based on documentation of the current state of the art and the ad hoc panel's own evaluation of selected water and land applications of ferrocement, detailed later in this report.
Recommendation 1: Exploratory Research into the Full Range of Ferrocement Applications[edit | edit source]
The panel recommends that ferrocement be subjected to a wide-ranging program of research and development to explore all its potential uses. Such R & D is likely to produce many valuable applications for the developing world.
Some applications require laboratory analysis (e.g., interactions between stored food and mortar surfaces); some, structural testing; some, demonstration and pilot trials. Other are so speculative that only studies on paper are warranted at present. Research institutions, engineering laboratories, corporations with R & D capability, technical schools, universities, or innovative individuals can engage in this work. Exploration of these ferrocement applications is exceptionally well suited for work on location in the developing world, but a role for research in industrialized nations exists. Although this report stresses less sophisticated applications, ferrocement is adaptable to sophisticated technology, too. Factory-fabricated precision components made from ferrocement may ultimately be the main use of the material. One particularly promising area for more sophisticated R & D is in replacing ferrocement with chopped-wire concrete in which randomly placed short lengths of wire, mixed in with the mortar, take the place of wire mesh.
Following is a list of individual applications the panel felt were particularly worthy of detailed investigation. Some of these applications are specifically discussed in Recommendations 2-6. They are included here to convey a sense of the range of uses for ferrocement. (See also Figures 1-5.)
FIGURE 1: Water-conveying troughs, 20 mm thick, are mass-produced in precast ferrocement units in the USSR (Drawn from diagram in Kowalski, T.G. "Ferrocement in Hong Kong." Far East Builder. July 1971, p.29.)
POTENTIAL APPLICATIONS OF FERROCEMENT
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Fishing and Cargo |
Boats Grain dryers |
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Tugs and Barges |
Copra dryers |
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Bridges |
Greenhouse, packinghouse, and drying tables |
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Docks and Marinas |
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Permanent food-storage dumps |
Pads for drying tea, coffee, cocoa, coconuts, other oilseeds, peppers, spices, etc. |
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Seed (vegetables, etc.) storage |
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Starch, flour, sugar storage |
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Silage storage |
Cattle feeders and water troughs |
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Edible oil storage (olive, peanut, cottonseed, palm, etc.) |
Cattle dips |
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Water storage (drinking or irrigation) | |
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Grain storage (rice, wheat, corn, sorghum, millet, etc.) |
Pipes and irrigation conduits |
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Ovens and fireplaces | |
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Manioc-soaking vats |
Slabs or shingles for roofs |
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Fermentation tanks for cocoa, coffee, etc. |
Decorative panels and tiles |
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Wall paneling | |
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Retting tanks for sisal, jute, hemp, etc. natural |
Floors |
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Telephone and power poles | |
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Gas tanks (for liquid and gas) |
Lining for tunnels and mines |
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Stakes for supporting vine crops, tomatoes, beans, etc. (for termite resistance) | |
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Cooling towers |
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Sewage troughs, lagoons, septic tanks, and other treatment facilities |
Pothole repairs (squares of ferro- cement sized and laid in the hole) |
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Guttering |
Timber-treatment enclosures |
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Leather-processing facilities |
Shutters and formwork for use in standard concrete construction |
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Dyeing vats |
Recommendation 2: Ferrocement for Indigenous Boats[edit | edit source]
The panel recommends ferrocement as a substitute for materials now used in the construction of traditionally shaped, indigenous boats. This application deserves widespread dissemination, a function that technical assistance agencies might well assume. The record of successful experiments confirms the technical feasibility, but field trials or demonstrations may be needed in some developing areas to overcome local resistance to innovation in boatbuilding.
The Food and Agriculture Organization of the United Nations (FAO) and the United Nations Industrial Development Organization (UNIDO) have taken the initiative in introducing ferrocement in developing countries and demonstrating its importance in a developing-country context. Thus far, however, these ferrocement-based technical assistance projects have been oriented toward larger, oceangoing trawlers with sophisticated western-style hulls, with the objective of increasing commercial fishing capability. Commercial fishing on this scale requires a considerable land-based organization to preserve, transport, and market the product, and the cost of large fishing boats represents an investment that subsistence-level fishermen cannot afford. In this report we are concerned with individual boatmen, whether commercial or subsistence, who would benefit from the low cost, long life, and easy repairs of small, familiarly shaped and familiarly propelled ferrocement boats.
Improving such craft will not initially have the same effect on economic development as introducing fishing trawlers. Yet, the ready acceptance of cheap, traditionally shaped boats could significantly affect economic development because of the much larger number of boats involved and the greatly increased life expectancy over their wooden counterparts.
Ferrocement's unique characteristics-low cost of materials, strength, ease of maintenance and repair-recommend themselves particularly to the fabrication of small, "native" craft. The usual curved displacement hulls of indigenous craft are appropriate for this material. Small ferrocement workboats can be built on site, by local (but supervised) laborers who are usually available and low cost. Because these boats are mainly hull, and therefore without costly fittings, the builder's savings are maximized. Never far from land and usually in fresh water, small workboats undergo less stress than deep-water vessels and require less stringent technology and quality control. Moreover, existing wooden craft are often so heavy that conversion to ferrocement sometimes yields boats equivalent or lighter in weight.
Since design improvements can be added incrementally, a traditionally shaped boat might, over the years, also be improved in design. In particular, the use of ferrocement allows all the complex curves of planked wooden boats, as well as the more complex curves that are not possible in wood but would improve the boat's performance.
Ferrocement is free from attack by teredos (shipworms), wood rot, and other hazards of the tropics. Furthermore, ferrocement boats are inherently strong enough to be powered, some comparable wooden boats are not strong enough to take mechanical power.
Recommendation 3: Ferrocement for Food-Storage Facilities[edit | edit source]
The panel believes that the urgent need to preserve grain and other food crops in developing countries justifies extensive field trials in the use of ferrocement for silos and storage bins. The existence of successful prototypes suggests that little more research is needed, other than techno-economic and design studies for given localities.
In tropical regions, high temperatures and humidity promote the growth of mold and rot on foodstuffs, destroy moisture-sensitive materials such as bagged cement and fertilizer, and encourage thermal or ultraviolet degradation of many products. Insects, rodents, and birds also take an enormous toll. Perhaps 25 percent* of each year's food crop in the developing world is rendered unfit or unavailable for consumption because of improper handling, storage methods, and facilities.
Hundreds of ferrocement boats floating on the world's waterways demonstrate that this material is watertight, and other experience has shown that ferrocement does not readily corrode in the tropics.
Experience in Thailand and Ethiopia** has shown that ferrocement grain silos can be built on site very inexpensively, using only one supervisor and unskilled labor. A simplified version of known ferrocement boatbuilding materials and techniques was used to build the silos. Measurable losses in the prototype silos are less than 1 percent per annum. Rodents, birds, and insects cannot gain entrance. Since these ferrocement silos are airtight, the inside air is quickly deprived of oxygen by the respiring grain, and insects (eggs, larvae, pupae, or adults), as well as any other air-breathing organisms introduced with the grain. are destroyed.
This safe means of storing grains and other foods such as pulses and oilseeds could help farmers in the developing world to become more self-reliant, and could contribute significantly to a country's economy and food reserves.
Recommendation 4: Ferrocement in Food Technology[edit | edit source]
In view of the properties, availability, ease of manufacture, and reliability of ferrocement, the panel recommends a serious, wide-ranging effort by research organizations to investigate the use of ferrocement to replace steel- particularly stainless steel-in manufacturing at least some units of basic food-processing equipment.
Many foods-highly perishable, irreversibly affected by temperature changes and biological and chemical contaminents-are lost to mankind because there are no rural processing plants to preserve, convey, or process food products soon after harvest. In many developing areas, high construction costs prohibit the use of even simple manufactured equipment. These costs are largely due to the traditional use of stainless steel, expensive on any account, but especially so in terms of foreign exchange when it has to be imported.
If ferrocement food-processing equipment (perhaps with an inert surface coating) can be developed, it may improve levels of nutrition and lend itself to labor-intensive, cottage-industry food processing in developing countries.
Some advantages of ferrocement for food-processing equipment are its (1) fabrication from mainly local materials; (2) structural strength and reliability, (3) ease, economy, and versatility of construction, (4) ease of maintenance and repair; and (5) easy-to-transport raw materials.
Extensive preliminary laboratory research is needed, particularly to investigate the sanitary properties of ferrocement structures and their ability to meet other specifications for food processing. Nevertheless, the panel believes that the effort is worthwhile in view of ferrocement's apparent suitability for
· Processing of fruit and vegetables for preservation.
· Fermentation vats for fish sauces, soy sauce, beer, wine, etc.
· Storage vats or tanks for fruit juices, vegetable oil, whey, or drinking water.
· Many other purposes-spray driers for milk, driers for copra, cooking stoves or ovens, dairies, freezing chambers, and slaughterhouses.
Recommendation 5: Ferrocement for Low-Cost Roofing[edit | edit source]
The panel believes that ferrocement may prove a suitable material for low-cost roofing in developing countries. Applied-science laboratories in developing countries and technical assistance agencies should seriously consider this area for field trials and techno-economic studies.
Adequate shelter is an essential human need, and a roof is the basic element of shelter. But current materials are not meeting the need for roofs. The more-than-80 developing countries in the world suffer from housing shortages resulting from population growth, internal migration, and sometimes from war and natural disaster. For most dwellings in developing countries, a durable roof constitutes the major expense. Roofs made of cheap local materials, such as scrap metal, thatch, or earth products (sand, mud, rock), are usually unsafe and temporary. A secondary problem is the need for adequate and durable supporting structures. In some areas, scarce wooden supports are weakened by decay and insect attack.
Ferrocement represents a potential solution to roofing problems because of its relatively low cost, durability, weather-resistance, and particularly its versatility. Unlike most conventional materials, ferrocement can be easily shaped into domes, vaults, extruded type shapes, flat surfaces, or free-form areas. Because ferrocement is easily fabricated, even in rural areas, by supervised local labor using mainly indigenous materials, it seems an excellent medium for on-the-site manufacture of small or large tiles (shingles) or other roofing elements. Where wooden timbers are very expensive, ferrocement beams might be made on site to replace wooden structures used to support indigenous roof coverings. Its most economical use, however, appears to be for fairly large-span roofs.
Ferrocement is not commonly used for roofing because its promise has not generally been recognized. Its use, particularly in developing countries, must be preceded by more research and experimentation in design and production techniques suited to construction by unskilled labor.
Recommendation 6: Ferrocement in Disaster Relief[edit | edit source]
The panel recommends ferrocement for careful consideration by disaster-relief organizations. This recommendation combines all the potential applications in developing countries considered by the panel.
After fires, floods, droughts, and earthquakes, the needs for food, shelter, and public health facilities are urgent. Transportation is often disrupted by destruction of roads, bridges, boats, and airstrips. Supplies of bulky conventional building materials may be stranded outside the disaster area, whereas the basic ingredients of ferrocement may be available on the site or easily transported.
The versatility of ferrocement also reduces logistical supply problems: wire mesh, cement, sand, and water can be substituted for the metal used for roofing, woods or plastic for shelters and clinics, asphalt for helipads, steel for bridges, and so on. Moreover, most ferrocement structures, though built for an emergency, will last long after the emergency is over.
In the panel's opinion, ferrocement could be used at a disaster site for many purposes:
· Transport facilities, from simple boats to barges, docks, marinas, helipads, and simple floating bridges or short footbridges-as well as road repairs.
· Food-storage facilities, quickly designed to local needs and quickly built, to preserve emergency food supplies.
· Emergency shelters such as, for example, the quonset type of roof, which is easy to erect and highly efficient.
· Public health facilities, such as latrines and clinics, built with ferrocement roofs and stucco-type walls of the same wire mesh and mortar.
To prepare for the use of ferrocement in disaster relief, demonstrations in simulated emergencies could be arranged for national and international relief agencies; and cadres of ferrocement workers could be trained in emergency applications and the supervision of local laborers at the disaster site.
Recommendation 7: A Coordinating Committee[edit | edit source]
The panel proposes that a multidisciplinary Committee for International Cooperation in the Research and Development of Ferrocement for Developing Nations be established, composed of experts from countries that have achieved high competence in using ferrocement, including the Soviet Union and the People's Republic of China. The committee might be established under the auspices of such agencies as UNIDO and FAO, which already have similar groups concerned with other technologies.* No existing group is available to agencies in developing countries who seek competent advice; yet such an international committee of experts is required at least until adequate standards and safeguards for ferrocement construction** become available- particularly for deep-water uses. Such a committee could help to avoid repetition of several hapless ferrocement enterprises of the recent past.
The proposed committee should have, as a minimum, the following responsibilities:
- To improve communication and cross-fertilization among all the areas of expertise involved (engineering, chemistry, architecture, agriculture, food science, construction, fisheries, boa/building);
- To convene meetings that provide opportunities for communication among the experts and technicians; and
- To provide direction and catalysis for the ferrocement training facilities described in Recommendation 8.
By these actions the committee could further the rational and effective introduction of ferrocement technology into developing countries and encourage research and development to move in an efficient and purposeful manner.
Recommendation 8: Ferrocement Training Facilities[edit | edit source]
The panel recommends that training facilities in ferrocement technology and application be established. Otherwise, the present serious shortage of trained staff to assist or advise in ferrocement construction projects may limit the establishment of high-quality programs.
The panel strongly believes that ferrocement's potential justifies the location of such facilities in, or close to, the developing world.
Two existing programs in the South Pacific deserve attention and replication. In New Zealand, the government is funding a training school for ferrocement marine construction. UNIDO has a program in Fiji in which villagers travel to a central boatbuilding yard where they work together to build a "village" boat.
The ferrocement schools proposed by the panel should
- Train personnel from developing countries to establish water and land ferrocement construction facilities and to supervise construction projects;
- Prepare personnel to establish country- or local-level training schools; and
- Produce audiovisual materials.
These ferrocement training schools could be grafted onto existing technical institutions or set up as separate establishments.
Recommendation 9: An International Ferrocement Information Service[edit | edit source]
Because of rising interest in ferrocement, the panel recommends the establishment of an international service to collect and disseminate information on ferrocement science. Such a service could prevent unnecessary duplication of research and development and ensure that an interested developing country is fully informed of relevant experience with ferrocement in other parts of the world.
This service should be particularly important for fabricators of specific products who wish to know how ferrocement will work for them. Because of the diversity of industries that are potential users of ferrocement and the tendency for individual industries to build up their knowledge independently, the availability of a centralized information service could help promote an efficient development of ferrocement technology.
The information service might well be set up at an academic or research institution already possessing competence and ongoing programs in ferrocement technology.
The information service should have at least the following functions:
- To maintain an information bank and inquiry referral service on ferrocement;
- To disseminate information on research and development efforts and on advances in ferrocement technology and experiences in applying it; and
- To help developing countries identify experienced ferrocement companies and consultants, especially those with experience in developing countries.
