Micro Concrete tiles, mud bricks, pozzolanic cement: EcoSur - Home

As en enrichment to the theme of EcoMaterials 2005, connecting science with the grassroots, this website is highlighting different experiences with this focus. This update features development of tevi equipment to produce MicroConcrete Roofing tiles. The top quality tile-making equipment is used throughout Latin America as well as in Africa, Asia, Central Asia. The development of tevi is the story of an audacious adventure that responds in a high-level scientific manner to requests from the grassroots.

Connecting science and the grassroots: The “tevi” experience

Demand for reasonably priced and reliable equipment in Latin America was so great in 1991 that CECAT had to risk lancing the first production run on the basis of its local field testing. By March of 1993 the first “tevi” equipment was on the market.

CECAT, The “Center for construction and Tropical Architecture” at the Technical University of Havanna learned of MicroConcrete Roofing technology in early 1991. Within a few months it became clear that Cuba would opt for MCR, as national authorities on construction and housing were pleased to encounter a viable roofing alternative.

CECAT first sought a favourable commercial agreement with the market leader for the tile making equipment, either for bulk orders or licensed production. That same year, at the First Latin American MCR Seminar in the Dominican Republic, delegates from 11 countries requested that reliable equipment become available at lower prices and with terms of credit. Both equipment producers present clearly stated that they could not respond to this request. This was the signal to CECAT to begin to develop its own equipment.

Engineering is the first problem

Equipment development involves several specialties and strong institutional backing. While the vibrating table presents multiple small problems to be solved, production of moulds is based upon one basic decision: injection moulding or not. Only injected moulds will fulfil high demands for true shape, strength and longevity.

Whatever the decision, serious equipment producers must be prepared to invest hundreds of high quality man-hours into a first prototype, which undoubtedly would have to be tested and improved on several points, which implies many more hours of expensive expertise.

Multidisciplinary effort

Specialists from within CECAT and from the Mechanical Engineering Faculty of the University designed a new type of machine, based upon a rotating vibrating table which would speed up production significantly. While they were still working on the prototype, the provincial government of Holguin decided to produce this model and go ahead with tile production. They did not want to wait any longer, as more than one year had passed since they were first exposed to MCR tiles, and the housing demands were great.

CECAT also recognized the urgency to respond to market requests. After a prototype of the single table machine was operating successfully, a well equipped commercial company began to produce the first series of vibrators.

It was clear that tooling for mould production implied high costs; there was no room for experiments. Good moulds were examined, their form computer-analyzed and their cross-sections inspected. It became evident that although the shape was good, the moulds were not quite as perfect as everybody had believed. After long discussions between the directorate of CECAT and the engineers it was decided to produce a mould which would be compatible with the market leader, but which would eliminate the small problems which had been discovered. The new mould would produce conical tiles in order to provide a better fit for 8 and 10 mm tiles, and would be stronger than the British product.

Actual production of the injection mould was quick and unproblematic because factories with the most modern equipment were able to take on the task. One firm was involved in design and tooling, another in the injection technology. However, it did engender high costs, apart from the previous engineering work done by CECAT and the commercial companies. The specialists rapidly identified the proper type and quality of the raw material and production began on the most modern equipment available with an injection force of more than 100 tons.

 “Tevi” stands for “Teja Vibrada” (vibrated tile) and is produced in Havana under the guidance of CECAT.

Marketing is not easy

At the time of equipment development, CECAT was already part of the Latin American MCR Network. Grupo Sofonias, which coordinates the Latin American MCR Network, also responded to the participants of the first Latin American Seminar. CECAT asked Sofonias to serve as a marketing channel because of the complications of the Cuban situation internationally. Thus, in order to facilitate access to reliable equipment it formed a commercial branch called EcoTec. However, it was clear to everybody involved, that equipment would have to be available in each country, to be bought off the shelf. This involved additional risk capital, which was assumed equally by CECAT and EcoTec.

Profits from the first hundred sets of equipment were used to pay off debts to the commercial firms which produce the machines and moulds, and have been reinvested in the production and shipment of more equipment. It is by no means fast-buck business. Without the large subsides that CECAT was able to draw from within the Cuban system and the financial collaboration of Cuban companies this development would not have been possible.

Development of this business has been possible because of the conviction of the parties that this technology is a real alternative for the Cuban roofing dilemma as well as other third world nations. Cuban brain-power and infrastructural facilities combined with the network contacts of Sofonias provided a solid basis from which to launch this audacious adventure.

Today

In the 12 years since launching “tevi” the original injection tool has undergone  reconstruction and  some 200,000 moulds have been produced, About half of them were distributed in Cuba and some 96,000 have been exported all around the world. More than 350 vibrating tables have been produced for the international market, in recent years most of them in Ecuador.

“Tevi” has undergone scrutiny by producers and users as well as a thorough technical evaluation by the BASIN network who concluded that “tevi” were clearly the best moulds available on the market, and at the same time the most affordable on the international market.

Many sets of equipment have been producing for more than ten years and so far none of the clients has claimed any problem with the moulds, many people have re-ordered. Of course this is somewhat different with the vibrating table with its moving components that wear down after some years and have to be repaired or replaced.