Methods for Reducing the Cost of Cementitious Building Components in Developing Countries, with Particular Reference to Rainwater Harvesting
Gwilym T. Still
A thesis submitted in partial fulfilment of the requirements of Doctor of Philosophy in Engineering (2007)
Cementitious building components, although widely used in low-income countries, are too expensive for many applications related to low-income housing. This thesis explores three options for reducing component cost:
- Use of local fine aggregates, often with clay contamination, instead of low-fines sands transported from a distance.
- Improved designs, to achieve better material economy.
- Change of production environment, from on-site to component prefabrication followed by transport to site.
Water storage tanks for rainwater harvesting were used as the example for component design, and as a case-study for considering the effect of changing the production environment. The work showed that:
- In some cases, use of local aggregates will give a cost saving of around 10%.
- Improved design can give significant reduction in materials usage, of up to 40%.
- Off-site prefabrication of components, followed by on-site assembly to produce the desired product, does not seem preferable to the prevelant practice of entirely on-site production from raw materials. However, factory-based manufacture of complete products, followed by transport to site, has a number of attractions over entirely on-site production.
Out of the three options examined, improved component design offers the greatest benefits for the case study considered.
Keywords: Rainwater harvesting, cement, tank, clay-contamination, developing countries.
