Changes

* Admixtures can be added to the concrete mix in order to reduce the amount of water needed. Research has shown that superplasticizers work best by reducing the amount of water that needs to be added when mixing concrete, which results in 35% less shrinkage. The resulting end material is stronger and can reduce the amount of micro cracks in mortar by half compared to normal mortar while resulting in 76% fewer leaks. In general, the amount of plasticizer to be added should not be greater than 2% of the dry material weight. A plasticizer that can be used that is possibly available is household washing up liquid. In hot climates though, more research is needed in the field application of plasticizers, since the reduction of water used (and increased strength of product) may not be that great due to more water needed to prevent drying out between mixing and application.

'''Stone Masonry''':

* In Somaliland it cost between $39 - $43 per m3 of storage for a new berked and $8 per per m3 for a rehabilitated berked, excluding about 30-45% of local contribution (e.g. 493m3 new berked = $19,550; rehabilitated existing berked = 4,000 USD). In India, stone masonry sub-surface tanks cost $28 per m3 of storage (35m3 tank cost $990). <br>