Message-ID: <TCPSMTP_GEN.19833.5092@bbs.colis.com> Date: Tue, 28 Apr 1998 13:17:56 -0400 From: Yvonne Sobers <mailto:asante@COLIS.COM> Subject: Compressed Earth Blocks for Roadbuilding To: mailto:DEVEL-L@AMERICAN.EDU
Uwe gave me some helpful information on the technology of using stabilized compressed earth blocks (SCEB) for low-cost road building. Does anyone else on this list have any experience or knowledge of this technology? Any email addresses of persons/organizations that I might contact for further information?I attach some of the info that I have acquired since Uwe mentioned the SCEB technology. I would appreciate feedback, particularly on email addresses for the sources of information that I mention.
Yvonne
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Stabilized Compressed Earth Blocks
The technology for making earth blocks is an upgrade of indigenous technologies found widely in Africa, India, the Caribbean, and Latin America. Earth construction is used in:
* The "daub" of Jamaica's wattle and daub traditional buildings * Adobe - sun dried mud blocks traditionally used by Native American Indians and lasting one to four centuries * Cinva, referring a particular brand originally popularized by the Whole Earth Catalog. * Rammed earth, referring to a monolithic earth wall compressed between movable forms * Compressed Earth Blocks (CEB) which is the generally used term for the current technology * Stabilized Compressed Earth Blocks (SCEB), using limestone as a stabilizer
The technology has been used for constructing houses, but has more recently has been introduced for road construction.
SCEB is made by pressing earth into a block. The technology may be comparatively high - with a hydraulic ram - or relatively low - with a lever action press. SCEB is increasingly adopted in developed and developing countries such as India, Africa, USA, Australia, and new Zealand. The Unites States Army is reported as using SCEB for building emergency roads, and SCEB roads built in Mozambique are called "Italian Roads" because they are built by Italian engineers. Blocks can be made from earth stabilized with limestone, and then laid (with no curing time required) on existing surfaces. The SCEB road surface is reported to be more effective than concrete, and can be repaired by replacing blocks.
A European consortium is said to be promoting SCEB as a building methodology for developing countries, and the French section of the group has developed expertise in using SCEB. Stabilized compressed earth blocks are created using a variety of machines such as:
* Cinva-Ram invented in South America. It uses human labor, is relatively inexpensive. Two people working for one day can make about 250 to 500 blocks in a day. * Fuel-powered machines that are expensive and can produce thousands of bricks in a day. * An inexpensive innovation that has been invented in Auroville, India. It can make a wide variety of sophisticated block shapes using human power. This machine was demonstrated at the UN Habitat II conference in Istanbul.
Data from the U.S. Geological Survey show that 65-70 percent of the soils present on the Earth's surface can be used to make compressed soil blocks. Typically, these soils contain 85-100 percent sand, silt and clays. Useful soils routinely contain 10-30 percent clay, 10-30 percent silt, and 40-70 percent sharp sand. The rest can be rock under 1 inch in diameter.
Sources of information on SCEB technology are CRA Terre (France), SKAT ( Swiss Centre for Development Cooperation in Technology and Management), Tierra Sol y Mar (California), and Development Alternatives (India). Development Alternatives has a website to which Uwe directed me, but the email address given on the website does not seem to guarantee response.