Interlocking soil-cement blocks serve as a cost-effective alternative to the traditional fired clay brick.
An old idea with new urgency, interlocking soil-cement blocks allow for the quick and cost-efficient construction of housing units and other buildings. Bricks anyone can make and that anyone can build with – an ideal, cost-effective solution, especially in the developing countries of Africa and Asia, for example.
One of the advantages of interlocking blocks is that they can be dry-stacked with no mortar, which increases the speed of construction. In Uganda’s urban areas, for example, where 53 000 homes are needed annually to maintain population growth, clay bricks are among the most common building materials. Interlocking blocks, which can be compressed in manually operated machines and dried in the sun, provide an affordable and environmentally sustainable alternative to clay bricks.
According to an article by the World Academy of Science, Engineering and Technology, “Behaviour of masonry wall constructed using interlocking soil-cement bricks”, walls constructed out of well compacted soil have adequate compressive strength under dry conditions; however, they will lose their strength under adverse moisture content.
Soil can be improved and used as a building material for various types of structures by adding stabilisers. Properly stabilised, consolidated, well-graded soil that is adequately moisturised, mixed and cured will provide strong, stable, waterproof and long-lasting bricks.
The concept of interlocking soil-cement blocks is based on the following principles:
• The blocks are shaped with projecting parts, which are aligned horizontally and vertically, eliminating the need for specialised skills.
• Bricks can be laid dry, which means no mortar is required and a considerable amount of cement is saved.
• Each block contains vertical holes, which reduce the weight of the block and allows for the insertion of steel or bamboo for reinforcement.
• The length of each block is exactly double its width, which allows for exact alignment at the right angles.
Interlocking blocks are produced in specially designed moulds that allow for either manual or mechanical compression. What makes this method ideal for rural communities, is the fact that the materials required for production and construction are almost always locally available. The structural stability and durability of interlocking bricks are much greater than these offered by timber construction. Unlike timber, interlocking bricks are immune to termite and other insect damage. Vulnerable and high-stress parts of a building can be reinforced by running bars through the aligned holes of the bricks.
Interlocking soil-cement blocks are an excellent example of how environmentally-friendly construction technologies can be made more affordable and accessible to the poor.
Full thanks and acknowledgement are given to the World Academy of Science, Engineering and Technology, “Behaviour of masonry wall constructed using interlocking soil-cement bricks” and www.unicef.org for the information given to write this article.