Tannin powder is an essential ingredient in the leather industry. Used to treat or tan hides, tannin preserves the leathers flexibility and makes it resistant to rot. Chile imports up to $1 million of natural plant tannin yearly, mostly from Argentina.
Being a coastal nation, Chile is subject to serious corrosion problems from sea water. It imports rust transformers and inhibitors for steel at considerable cost. Researchers have now demonstrated that tannin solutions can be used as anticorrosives at much less cost.
Chiles radiata pine plantations are providing a new source of natural tannin for both the leather industry and for producing anti-corrosives. Large volumes of pine bark are available as a waste product of the timber industry. The bark contains 15% tannin, and can be used to produce a tannin mixture suitable for commercial use. The bark is crushed and heated with water at 80°C, then cooled and decanted. An evaporator removes the excess liquid. Tannin can be produced in liquid or powder form.
The DITECO tannin plant in Chile is now producing tannin from pine bark provided by local sawmills. Local tanneries are mixing the tannin with imported tannin for use in treating leather. The plant employs approximately 40 people, with an additional 20 people gathering bark.
Two anticorrosive products manufactured from tannin have now been developed and patented in Chile and Brazil. The first is a rust converter for metal. It can be used as a primer before painting steel, and will convert existing rust into a smooth, sealed surface. Tests demonstrated that the pine tannin rust converter works better than commercial converters and as well as sandblasting, the most common but expensive method for cleaning steel surfaces before painting. When applied to buried pipes, bridges, and docks, the rust converter eliminates the need for sandblasting, reducing the cost of surface preparation and cleaning by 30 to 40%.
The second product is a mineral oil-tannin compound used as a rust inhibitor for cold-rolled steel. Cold-rolled steel exposed to the elements during transport and storage is generally protected from corrosion by being immersed in mineral oil after lamination. Protection from rust lasts up to four times longer when tannin is added to the mineral oil. This reduces the cost of cleaning rusted steel before use.
Solutions of another tannin-based product can also be used to prevent corrosion of boilers and other equipment used to produce steam.
Small and medium-scale industries with access to natural plant tannin.
Guillermo Matamala Rivas, Facultad de Ingeniera Universidad de Concepcin Casilla 53-C, Concepcin, Chile Fax: 56-41-222712; Telex: 260157 INCON CL
The Programa Agroqumico of the Faculty of Sciences l and Technology of the Universidad Mayor de San Simn (UMSS) in Cochabamba, Bolivia, has applied steam-extraction technology to make Bolivia self-sufficient in the production of several essential oils such as menthol, citral, and eucalyptol. Oil extraction using steam is a comparatively simple and inexpensive process that is readily adaptable to rural areas. The primary steam-extraction techniques can be learned easily by the rural population in a matter of weeks and do not involve sophisticated industrial technologies.
This technology has the potential to create jobs and generate incomes in rural areas. Within 5 years, the project has almost eliminated Bolivias annual Can $800 000 of imports of menthol, citral, and eucalyptol oils needed for the production of detergents, soaps, ointments, and other domestic products that have a combined Bolivian market value of $3.5 million. Since 1990, Bolivian manufacturers have obtained almost all the oils they need from the Programa Agroquimico. In the long term, the project could make Bolivia an exporter of the oils (some exports to Brazil, France, and the US have already begun).
The use of the simplified extraction techniques is creating jobs and generating incomes for many disadvantaged farming families in Cochabamba province, one of the poorest in Bolivia. Ten cooperatives are at work gathering the leaves and grass for extracting oils and processing the natural extracts. Each co-op has obtained a steam distillation unit from the program. Each unit is associated with a community of 80-130 families. The crude oils they produce are sold to the university, which in turn refines them into higher grade oils. The purified oils are sold to Bolivian manufacturers of candles, soaps, and other products.
The program is successful enough that an additional 36 communities have approached the researchers to start the processing of eucalyptus and lemon grass. At current prices, average profits from each distillation unit are estimated at $30 000 per year.
Each co-op has control over how their profits are distributed. A womens co-op has been the most successful so far. A detailed study is currently underway to assemble all the necessary information to transfer the technology to other regions and countries.
Production of eucalyptus oil can also contribute to mitigating erosion and environmental damage by maintaining the natural tree cover, since the process only involves cutting the tree branches, which regenerate quickly.
Availability of oil-bearing renewable resources, such as eucalyptus trees, lemon grass, and mint, and the conditions for growing them.
Each distillation unit comprises a 5-cubic metre extractor, a steam-boiler, a condenser, and a separator. Constructed from local materials, the equipment costs about $10 000. The pay-back period is estimated at 3 to 4 years.
Rural or small-town communities with available supplies of oil-bearing plants or trees, such as eucalyptus or lemon grass, and the right conditions for growing them. Eucalyptus, lemon grass, and mint can all grow in poor agricultural conditions, on land that might otherwise remain unused.
Jorge Soriano Ferrufino, Project Leader Programa Agroqumico Cordeco-UMSS Casilla de Correo 992 Cochabamba, Bolivia Tel.: (691-42) 32548 Telex: 6363 UMSS BV Fax: (591-42) 33648
Peru is the major supplier of carmine dye, a natural, red colouring agent derived from the cochineal insect that is used in foods, drugs, and cosmetics. Global restrictions on artificial colorants in food and other consumer items is giving Peru a considerable advantage in the world market. By 1991, many synthetic red dyes were prohibited in the United States, which put Peru in a unique position. Currently, Peru furnishes 80% of the worlds cochineal supply - about 40% as a dye and 60% in insect form.
The Peruvian government wants to increase the processing of the carmine dye in Peru, given that cochineal are plentiful, rural people are experienced in harvesting the insects and drying them, and extraction techniques are comparatively simple. By locating processing plants close to cochineal production areas, rural industry and local employment will increase. Currently cochineal farmers earn an estimated 10% of the revenue generated by cochineal. An estimated 50 000 people harvest the insects by hand, dry them in the sun, and sell them through intermediaries to carmine processors in Lima.
The extraction process is available to small-scale enterprises and NGOs including information on how to improve management of the cochineal insects during infestation, harvesting, and drying. Extraction of carmine powder from the insects involves boiling the insects in water, followed by filtration, precipitation, and washing and drying of the final product.
The Instituto de Investigacin Tecnolgica Industrial y de Normas Tcnicas (ITINTEC), in collaboration with Simon Fraser University, has improved the carmine dye extraction process to give a 24% yield of 72% pure carmine. Other commercial processes give 20-23% yields of 52% pure carmine. A new phase is exploring improved infestation, harvesting, and drying processes. A pilot production plant with a capacity to produce 5 kg of carmine per day has been successful. The technology is now being made available to the private sector, with the following criteria:
· Production units should be in
rural locations close to cochineal producers;
· A system such as producer co-ops should be used to share benefits with the cochineal farmers;
· Plants must be owned and run by Peruvians; and
· Owners should have the ability to sell the carmine dye abroad.
Access to cochineal and markets for the red dye. Cochineal grow on prickly pear cacti in the Andean region. The processing plant requires a fairly substantial capital investment, around US $400 000, suitable for medium-scale enterprises, but high for small-scale companies.
Cochineal exporters and producers as well as current producers of carmine who are interested in improving yield.
Cost and availability
ITINTEC can provide a cost analysis for implementation of the technology. The process is available by competitive bid to ITINTEC.
Dr A.C. Oehlschlager,
Canada V5A 1S6
Tel.: (604) 291-4884
Fax: (604) 291-3765
Ing. Guillermo Salas,
Telex: 20496 PE
A technique originally developed and patented in Canada in the 1970s is now being adapted to help address Chinas current lumber shortage and use residual wood from mills and logging which would otherwise be wasted.
The technique developed in Canada involves finger-jointing, mature green lumber using specially-formulated adhesives. This technique can be used on short, small, and crooked thinned-out logs that are currently thought to be useless. The bent wood is cut into sections, the wood ends are profiled into finger shapes and bonded together with adhesives to form a piece of straight and useful lumber.
The Canadian patent holder has waived the patent in China, and Chinese researchers have developed a similar method using immature green lumber as well as dried lumber and locally-made chemicals to produce the glue. Advantages of this technique are that it is relatively inexpensive, easy to adapt and use in small factories, and the products can be handled immediately for manufacturing operations. Although green lumber must be redried after joining to be useful to industry, this process can result in some deformation, depending on the type of wood used. Therefore, whether the finger-joints should be made of green wood or dried wood depends on wood species, uses of the end products, and local production and technical conditions.
The glue developed by the project is weatherproof, durable, stores well, and works especially well for bonding coniferous trees. The major species tested with the glue are poplar, Chinese fir, masson pine, and larch. Tests continue on other tropical wood species.
The technique could add 15 million cubic metres of wood annually to Chinas production of lumber, while using waste material and providing part-time income to rural people supplying wood thinnings from their farms and community woodlots. They can make up to 45% more selling the small-diameter wood for finger-jointing than selling it as firewood. This increases the economic value of the wood and stimulates farmers interest in planting trees.
In 1990, local Chinese factories produced Can $1 million worth of finger-jointed products. Several pilot plants were established for testing the finger-jointed technology and glue production; two commercial plants were set up to build components for truck loading beds; and a factory using the new technology produced laminated beams used in the construction of the 1990 Asian Olympic Games building.
By using waste wood to meet needs for lumber, the technology can contribute to reducing deforestation.
Supplies of otherwise unusable lumber and appropriate resin adhesives. The lumber can come from thinnings, fast-growing wood stands, crooked logs, used timber, and large branch wood, so long as there are no dead knots, decay, insect holes, or bark pockets on the ends to be finger-jointed.
To set up a finger-jointed lumber mill with an annual output of 3000 square metres, approximately US $4000 in capital outlay is required, as well as a US $2000 circulating fund and 80 to 100 employees.
NGOs, government, and the private sector interested in promoting small-scale rural industry. The technology could be useful in countries of the Asia Pacific region where there are shortages of timber.
Zhu Huan Ming Research Institute of Wood Industry Chinese Academy of Forestry Wan Shou Shan, Beijingm, Peoples Republic of China Tel.: 2582211 ext 431; Fax: 2581937
Bamboo mat weaving is a popular tradition in India and other parts of Asia. Rural dwellers, particularly women and tribal people, weave millions of square metres of mats. Although some of the mats are for household use, most are sold in the market to supplement family income. Over the last decade however, some of the largest consumers - commercial packers and house builders - began switching to plywood and synthetic materials causing a decline in the mat cottage industry and affecting the livelihood of the mat weaving community.
The production of boards from bamboo mats glued together constitutes a sound alternative to plywood made mostly from imported timber. The use of bamboo also conserves natural forest, which is being depleted at an alarming rate in India. The fast growth and maturation of bamboos and their easy propagation make them an important and inexpensive local substitute for plywood.
The Indian Plywood Industries Research Institute has developed a low-cost low-input technology using local raw materials (bamboo) and adhesives from industrial waste (black liquor) for the production of commercial bamboo mat boards. This technology produces a better product at a more affordable price for the consumer and stable prices for the mats will ensure better wages and living standards for the mat weavers.
This technology can be easily adapted by small-scale rural industries employing local labour with minimum skills. Bamboo mat board will supplement plywood, which is presently made mostly from logs and veneer imported at high cost.
The black liquor from pulpmill waste is being used to produce lower-cost adhesives for the bamboo mat board. This approach will decrease the amount of phenol needed to make the resin adhesive, thereby reducing the cost.
Testing of manufactured items, such as packing cases for horticultural products, especially apples, showed that up to 75% of the plywood could be replaced with the new bamboo mat boards. The cases are estimated to cost 15-20% less than the equivalent wooden packing cases. Bamboo mat boards will be used for low-cost housing, for crates, and for building grain storage rooms and bins presently made out of wood and plywood.
Cost and availability
Initial estimates indicate that the cost of resin for bamboo mat board is reduced by about 75% by using modified phenolic resin. Further reduction in cost is foreseen when black liquor-phenol-formaldehyde resin, which is being developed in the project, is standardized.
The Indian Plywood Industries Research Institute (IPIRI) provides technical assistance in establishing small bamboo mat board production units in rural areas. Negotiations for technology transfer to the Philippines and other interested countries are underway.
The rural housing industry and many cottage industries such as construction of packing cases will be the primary beneficiaries of this inexpensive alternative to plywood. The production of bamboo mat board will create employment for rural women and will generate additional income by reviving and expanding the bamboo mat weaving cottage industry.
Farmers will be encouraged to grow bamboo on their land, community property, and home gardens, benefiting from the short rotation of bamboo cropping (3-5 crops per year) and better prices.
Because of the increase in quality and the reduction in costs in bamboo mat production, entrepreneurs can now establish small-scale bamboo mat board factories. The production of bamboo mat boards is a labour-intensive process compared to plywood production and will therefore generate more employment.
Dr P.M. Ganapathy Indian Plywood Industries Research Institute PB No 2273, Tumkur Road Bangalore, India 560-022 Tel.: (812)394 231 and 394 341 Fax: (812)396 361
Resources and publications
Copies of the following technical reports are available from the institute on request:
· IPIRI. 1992. Techno economic feasibility of bamboo mat board manufacture. Indian Plywood Industries Research Institute, Bangalore, India (in press).
· Aswathanarayana, B.S. et al. 1990. A study on test methods for evaluating bond strength of bamboo mat board. (Doe. 4).
· Damodaran, K. 1992. Bamboo mat board apple packing cases. (Doe. 7).
· Zoolagud, S.S. 1990. Phenol-formaldehyde resin adhesives for bamboo mat board. (Doe. 3).
· Padmanabhan, S. et al. 1992. Glue line preservative treatment of bamboo mat board for interior applications. (Doe. 8).
The National University of Singapore, together with l Total Recovery Systems International in Toronto (formerly SCADA), have developed a user-friendly, flexible hardware-software system for monitoring and controlling industrial processes using inexpensive personal computers. The system, called Synapse, provides accurate, online measurement for quality control in small industries such as soap manufacture, cheese production, and other chemical processes. It is also useful for teaching and research.
The software package and an interface module allow the computer to be linked to instruments - such as data loggers, spectrometers, and pH meters - that monitor and control a wide range of processes such as adding ingredients, regulating temperature, and checking for colour and consistency. The system has many potential applications including such things as accurately measuring heavy metals in the environment, pH in fish ponds, and soil nutrients.
With Synapse the user can use analytical instruments by computer without any previous expertise or training in computer programming or electronics. The system is also easy to maintain, which makes it particularly applicable in developing countries. It reduces costs for small industry, where each measuring and control instrument has to be bought as a separate package at anywhere from US $1000 to US $5000 each. The Synapse package links all these instruments to a basic IBM for about US $1000.
Several important technological advances were made in the development of the system, including the integration of artificial intelligence techniques, object-oriented programming methods, and natural language processing. The operator uses a mouse to work out the basic structure of the process he or she wants to control. From a menu of icons, the operator can pull down pictures of valves, pumps, meters, liquid levels, etc. Each is automatically linked to a hardware interface. The operator then supplies the conditions that must be fulfilled for the equipment to operate. For example, someone might tell the program to open a valve when the temperature reaches a certain range. Once this information has been input, the systems extensive database allows the computer to decide what to do, when, and how.
The system is not rigid or frozen into specific sequences of action. In this way, the computer can decide what to do, while leaving room for the user to incorporate rule of thumb and shortcuts into the operating characteristics.
An IBM personal computer or clone. Most users are able to use the Synapse system without previous training. A detailed manual is provided to guide the user in mastering the system.
A wide range of industries including metal finishing, aquaculture, environmental control and monitoring, and factory automation. Because of the low cost of the software, the system is applicable to small- and medium-scale industries. Universities, colleges and research institutions can use the package for teaching, research and improving their experiments; hospitals can use it as a teaching and diagnostic tool. The system is currently being used in a pilot scheme for improved tea-drying in some of Sri Lankas tea factories.
Cost and availability
The Synapse hardware and software is commercialized worldwide through Eutech Cybernetics. Total cost is approximately US $1000, excluding the computer, for selected institutions in developing countries (the commercial list price is higher). This includes the software and any required hardware interface cards that link electronic gauges, valves, and other devices to the computer.
Dr Hari Gunasingham
56, Ayer Rajah Crescent
Family weaving enterprises own 85% of the looms currently in use in India and Pakistan. These cottage industries are competing for a domestic and export market where consumers are demanding more and more sophisticated cloth. There is a need to increase self-sufficiency in fabric production for the national textile industry, as well as to modernize the equipment of textile producers.
Small weaving enterprises can now earn 20 to 26% more by producing designed (geometric or floral) patterns rather than plain cloth. These designs are produced on the loom using a mechanical selection device called a dobby. Currently two types of dobbies are used: modern dobbies which are efficient, high speed (200 picks per minute) and expensive; and older, less efficient, cheaper dobbies used throughout the Third World. These local low-cost dobbies, copied from imports, are cumbersome, difficult to maintain and slow (100 picks per minute).
Pakistani and Canadian researchers have now developed a new dobby that is fast and efficient, while still relatively inexpensive and easy to make locally. Called PAKCAN, the dobby can reach speeds of 130 to 160 picks per minute and can be used on 82% of the shuttle looms in use today. Its advantages over dobbies in current use include:
· Superior stability;
· Perfect alignment of knives and hooks;
· Fewer components;
· Lighter and consumes less energy;
· Streamlined appearance and easy to manufacture, maintain, and operate.
The PAKCAN dobby provides a superior performance with low cost and low maintenance, and has the potential to increase incomes and productivity for the cottage weaving industry.
The PAKCAN can be used on shuttle looms with speeds up to 160 picks per minute.
Small and medium-scale weaving enterprises. There is already a demand for the dobby identified in Brazil, China, Egypt, Indonesia, Malaysia, Peru, the Philippines, Thailand, and Turkey.
Cost and availability
The dobby is expected to sell for as little as Can $800 (based on 30% profit margin and production of 100 units per month). Although this is still higher than current local dobbies (which sell for Can $250), the low maintenance costs and higher quality fabrics made possible with the PAKCAN dobby make it attractive to small weaving enterprises. A licensing agreement will be pursued once successful field trials in India are completed.
Pakistan Council for Scientific and Industrial
Lahore 54600, Pakistan
Tel.: 873866; Telex: 47115 PCSIR PK
Cable: CONSEARCH LAHORE
Mr Trevor Cornell
Mechanical Engineering Division
Manitoba Research Council
129 Niakwa Road
Winnipeg, Manitoba, Canada R2J 3T4
Tel.: (204) 945-6000/6619; Fax: (204)
In Jamaicas rural areas, there is a shortage of affordable housing, mainly because of the high cost of building materials. The Jamaica Bauxite Institute, in collaboration with the University of Toronto, has developed an inexpensive building brick made from the waste generated by the countrys aluminum industry, as well as from noncommercial bauxites.
The bauxite waste, or red mud, when impregnated with a sodium silicate solution, hardens naturally without the need for firing. Its use has many advantages: the raw material is easily available; it requires little energy; it develops local skills; it can be used more cheaply than cement to build schools, community centres, health centres, etc.; it lessens dependence on imported materials such as steel; the bricks are strong when dry; and there is little need of sand or cement. The bricks have the potential to provide cheaper housing and increase employment in rural areas.
A model building has been built to demonstrate the use of the bricks, and training of local people in the brick-making technique has been undertaken. Because labour costs are not significantly different for building a house from cement blocks or from bauxite waste bricks, training in self-help building is also important to keep costs down.
Another Jamaican organization, the Construction Resource and Development Centre, is developing cyclone-resistant housing using the bauxite waste bricks. Red mud could be used for other purposes such as water pipes and floors and could become an export item to other Caribbean islands.
The technology is environmentally friendly, uses waste from a major industry, and requires little energy (unlike production of cement blocks), thereby decreasing deforestation and dependence on imported oil.
Availability of red mud produced by the aluminum industry or access to other noncommercial bauxites. Sodium silicate is used as a bonding agent. Two major pieces of equipment are used: a pulverizer to grind the mud to the required particle size and a compactor to compress the mixed mud into the mould.
Rural people, governments, NGOs, and small businesses close to aluminum processing plants or other noncommercial bauxite material.
Dr Carleton Davis
The Jamaica Bauxite Institute
Hope Gardens, PO Box 355
Kingston 6, Jamaica
Tel.: 92-72070/1; 92-72073/9;
Telex: 2309 JAMBAUX JA.; Cable:
Dr J.W. Smith Department of Chemical Engineering and Applied Chemistry University of Toronto Toronto, Ontario, Canada K5S 1A1 Tel.: (416) 978-4020
Resources and publications
· It is envisaged that booklets, books, and video materials will become available after a proposed workshop on bauxite waste bricks planned for February 1992.
· Radio Qubec has produced a video program on the project. For information contact Franoise Bertrand, Radio Qubec, Socit de Radio-Tlvision du Qubec, 800 rue Fullum, Montral, PQ, Canada H2K 3L7. Tel.: (514) 521-2424; Fax: (514) 873-7739.
In Brazil, as in most of Latin America, increased costs of building materials - especially portland cement - have compounded a housing crisis affecting the countrys low-income population. In the search for alternative low-cost building materials, researchers are investigating the use of industrial and agricultural wastes.
Slag is the product of purifying iron ore into pig iron. It sits in huge mounds outside iron furnaces. Blast furnace slag (BFS) is the water-quenched slag that has a high vitrous phase. Brazil produces some 3 million tonnes of BFS per year, and its disposal is a crucial problem for the steel mills. Sold for about Can $5 per tonne, it is an inexpensive source of cement material.
A suitable cement is obtained by mixing ground slag with hydrated lime and gypsum (0.88: 0.02: 0.10 - BFS: lime: gypsum). Researchers in Brazil have designed and manufactured hollow wall panels and a prototype house using the BFS-based cement reinforced with coir fibres, which are widely available in Brazil and other Latin American countries. The hollow panels are 395 cm long and 90 cm wide, and are strong enough for use in load-bearing walls in single-storey buildings.
The process for making the panels is suitable for small scale industrial plants or even for manufacture on the building site. An ordinary pan mixer is used to prepare the material, which is poured into moulds that are placed on a vibrating table.
In a small plant, the cost of each panel is US $5.70 or an average of US $6.30 per square metre of wall, including labour and grout. This is considerably less expensive than ordinary brickwork, which costs US $8.00 per square metre. These savings may be increased with the development of better manufacturing plants, faster construction time, and the reduction of waste materials on the building site.
In a new phase, the Brazilian researchers are promoting the technology to small-scale panel manufacturers, contractors, housing authorities, architects, and civil engineers. A manufacturing and construction manual will be developed, as well as a video to promote the technology as an alternative for the provision of shelter to low-income people. A manual on the process has been prepared for the public in Portuguese.
Iron industry producing blast furnace slag; availability of good-quality lime and gypsum; coir fibres.
Government, NGOs, construction companies, producers of precast components, and local people building low-cost housing in iron-producing countries such as China, India, Indonesia, Mexico, and others.
Mr V.M. Joh/Dr Carlos Eduardo de Siqueria Tango Divisao de Edificaoes Instituto de Pesquisas Tecnolgicas do Estado de Sao Paulo Cidade Universitaria 05508 Sao Paulo CP 7141 (CEP 01000), Brazil Tel.: (011) 268-2211 Fax: (011) 211-4308 Telex: (011) 83144 INPT BR Cable: TECNINST
Dr Vahan Agopyan Escola Politecnica Universidade de Sao Paulo CP GI548, 05508 - Sao Paulo SP, Brazil Tel.: (011) 815-4322 ext. 336413452 Fax: (011) 2114308
To ease Rwandas housing crisis, attempts are underway to develop construction methods that use cheap, durable local materials. Technologies using minimal energy must be developed because of the increasing shortage of firewood.
Rwanda currently produces some 70 million fired clay bricks; 60 million are produced by cottage industries that are not mechanized, have no financing, and make inefficient use of materials and energy. Their workers have no training, so the quality and size of the bricks varies. Losses of up to 40% can occur using primitive ovens and supply is irregular.
With the cooperation of researchers from the University of Sherbrooke, Canada, researchers at the National University of Rwanda have developed methods for improving local production of fired bricks. These methods reduce losses, improve the quality of the bricks (they are stronger and of a standard size), reduce energy needs, protect the environment, and create new jobs.
· An improved oven that optimizes firing. It gives an even temperature and uses peat as well as wood for fuel;
· Additives to the clay, such as rice husks and sand;
· Locally manufactured manual presses;
· Drying bricks in the sun or the fresh air in sheds; and
· Locally manufactured insulation bricks (for oven construction and other purposes). The improved oven is made from bricks. The walls are three bricks thick, two of them being insulation bricks. The vault is a semicircle covered with a grill onto which a portland cement parging is fixed. A metal clamp collar surrounds the oven.
The first bricks to be fired in this new oven were an improvement over the previous homemade ones - they are one and a half times more resistant under compression.
Using rice husks in brick manufacturing produces a number of advantages:
· They strengthen the clay, which can be too malleable, and prevent cracks from developing during drying;
· They prevent the bricks from becoming misshapen when stacked up in the oven; and
· They improve firing in the middle of the brick.
In an initial comparison, brick losses dropped 40% to 0.2% with the improved method. The cost of building a simple inner wall using the new bricks was reduced by nearly half.
Deposits of acceptable-quality clay; rice husks or sand; the construction of the oven requires simple tools and the services of approximately five bricklayers. Regular and insulation bricks as well as steel bands and portland cement are needed.
Small producers of fired clay bricks, especially in Burundi, Kenya, Tanzania, Uganda, and Zaire.
Cost and availability
For the construction of the oven and fittings: RWF 300 000; ancillary costs (moulding, handling, fuel, and heater): RWF 1.768 per brick (compared with RWF 2.5 per brick using the traditional method).
Jean-Baptiste Katabarwa, Dean Facult des sciences appliques Universit rationale du Rwanda PO Box 117 Butare, Rwanda Tel.: 30272/30273 Telex: 22606 UNR RW Fax: 260-30858
Faculty of Applied
Quebec, Canada J1K 2R1
Tel.: (819) 821-3106
Fax (819) 821-7903
A collaborative effort between the civil engineering department of the Pontificia Universidad Catlica del Per and the architectural faculty of Concordia University, Montreal, has produced safer adobe housing for the poor in a major earthquake zone. Adobe houses are built of earthen brick. They are popular because adobe is easily available, inexpensive, the houses can be built by unskilled workers, and they are fire resistant. However, adobe lacks the strength to withstand earthquakes.
Earthen buildings house 66% of the rural and 35% of the urban population in Peru. In the 1970 earthquake, 50 000 people died and 60 000 houses were destroyed - a level of destruction that can largely be attributed to traditional housing styles. When an earthquake occurs, the walls of these houses collapse outwards and the roof of dried mud, which can weigh up to 10 tonnes, crushes the occupants.
The new construction methods that have been developed include several improvements such as reinforcing the walls with inexpensive bamboo or eucalyptus poles anchored to the foundation together with horizontal canes tied to the poles at every fourth row of bricks. The poles are secured to parallel wooden beams on top of the walls, which also act as roof supports. These structural changes allow the walls and roof to react to the vibrations of an earthquake as a structural unit rather than as separate elements.
The improved methods were tested at the Universidad Cat1ica on a seismic table which simulates earthquakes. The improvements have succeeded in making the adobe constructions resistant to the force of Perus strongest earthquakes.
Several prototype models of schools, health outposts, a small cheese-making enterprise, and community centres were built in cooperation with the Ministry of Health, the Ministry of Education, the FAO and community organizations.
Several methods of information dissemination, such as manuals, radio shows, and videos, were also tested. Scale models and photos proved the best means of illustrating the new technology.
The improved adobe housing requires the availability of soil, straw, sand and cane material. The practical application of the techniques requires no special skill other than that of a common mason.
NGOs, community groups, governments, and local people who use adobe as a construction material in earthquake zones.
Gladys Villa Garcia, Laboratorio de Estrcturas Antissmicas Pontificia Universidad Cat1ica del Per PO Box 1761, Lima 100, Peru Tel.: (51-14) 622-549 ext. 259 Telex: 20300 PE PB SMGL Fax: (51-14) 611-785
Professor Cedric Marsh Centre for Building Studies Concordia University 1455 blvd de Maisonneuve West Montreal, Quebec, Canada H3G 1M8 Tel.: (514) 848-3196
Resources and publications
· The Universidad Catlica has developed educational materials including manuals, videos, photos, and scale models. A technical report on the research was produced in Spanish under the title Ensayos de Simulacin Sismica de Viviendas de Adobe, Pontificia Universidad Catlica del Per, 1989.
The Centro de Investigaciones de Ingeniera at the Universidad de San Carlos de Guatemala and the Department of Civil Engineering at the University of Calgary are testing pozzolan cement as a substitute for portland cement in such applications as blocks and masonry mortar. Traditionally, portland cement is used in building. This is an expensive option given the high energy costs involved in producing it - it needs to be fired at high temperatures - and transporting it to its final market.
Twenty-five percent of Guatemala is in a volcanic zone that contains large surface deposits of a volcanic ash called pozzolan. Mixed with lime at a ratio of 80:20 or 70:30 (pozzolan:lime), natural pozzolan behaves like cement. Although some grinding is required to make it fine enough to work with, the pozzolan mix does not require firing which reduces production costs. In Guatemala, pozzolan cement currently costs approximately 60% of the cost of portland cement.
Pozzolan cement can be used for blocks, plastering, masonry mortar, and as a stabilizer for adobe walls and road bases. The project has tested the cement for strength and resistance to earthquakes. Four demonstration houses will be built using pozzolan and workshops are being used to encourage small pozzolan cement production plants in rural areas near pozzolan deposits.
About 50% of Guatemalas population lives in inadequate housing, mostly because of the high cost of building materials. Pozzolan cement production has the potential to both generate employment and reduce housing costs.
Supplies of usable quality pozzolan and lime, some skilled workers, building standards, and quality control. Efficient and low-cost local lime production is essential to keep the cost of pozzolan cement low.
Local building contractors and government agencies are building low-cost housing in regions of Africa, Asia, and Latin America where there has been volcanic activity resulting in accessible pozzolan deposits of usable quality. Processes and materials will differ slightly from one region to another.
Ing. Javier Quinones
Centro de Investigaciones de
University of San Carlos
Tel.: (502-2) 76.39.92
Fax: (502-2) 76.39.93
Dr Robert Day
Civil Engineering Department
University of Calgary
2500 University Drive NW
Calgary, Alberta, Canada T2N 1N4
Tel.: (403) 220-7489
Fax: (403) 282-7026
Resources and publications
Day, R.L. Pozzolans for Use in Low-Cost Housing: A State-of-the-Art Report, IDRC, Ottawa, September 1990, 157 pp.
Ferrocement technology, in which mortar (cement, sand, and water) is spread over a steel and wire or bamboo skeleton, is a simple and inexpensive new building method, with a wide variety of uses.
In the Philippines, ferrocement is being used to build cylindrical rainwater catchment tanks. Although the walls of the cisterns are only a few centimetres thick, they can withstand the water pressure because of the internal reinforcement with large-gauge welded steel mesh covered with fine wire mesh. In various countries, ferrocement has also been used to build silos, biogas holders, boats, roofing elements, biogas digesters, canal linings, and latrines. The technology is currently applied in more than 50 countries including India, Indonesia, Malaysia, and the Philippines.
The International Ferrocement Information Centre (IFIC) at the Asian Institute of Technology (AIT) was established in 1976 to ensure transfer of ferrocement technology, which has wide application in rural areas. Although the technique is simple in theory, the centre recognizes that translating it into a technically sound, socially acceptable, and affordable village technology requires detailed research and testing. It is therefore looking at novel approaches to teach the use of this technique to rural people.
Training is complemented with do-it-yourself brochures and booklets in local languages adapted for use by villagers. Technical information is repackaged to target specific groups, such as women (who are usually involved in construction) or extension workers in each country.
IFIC has agreements with 141 universities in 50 countries to teach ferrocement technology. IFIC has also created 50 reference centres in 32 countries and is seeking to create another 30.
A Ferrocement Information Network (FIN) was established in 1985 to facilitate and accelerate the flow of information among ferrocement users in developing countries. A directory of men and women and organizations knowledgeable in ferrocement technology is available. Network members also organize training programs and demonstrations in rural areas.
Adequate supplies of cement, aggregate (usually sand), and reinforcement (usually steel mesh, but other materials such as bamboo are also used). The technique is easily explained by demonstration, pamphlets, and videos.
Villagers and technicians working in low-income rural and urban areas. Technicians and engineers can access specialized bibliographies, directories, and computer software for the design of ferrocement structures, such as water tanks and roofing elements. As well, newsletters, brochures, and audiovisual materials are available through FIN and the various reference centres.
Arthur Vespry, Director Library and Regional Office Centre International Ferrocement Information Centre Asian Institute of Technology PO Box 2754 Bangkok 10501, Thailand Tel.: (66-2) 529-0900-13 Telex: 84276 TH Cable: AIT Bangkok Fax: (66-2) 516-2126 or (66-2) 524-5870