Southampton Solent University

Southampton Solent University with the Good Earth Trust promotes projects in Africa that utilise interlocking rammed earth blocks

Commercial brick kilns Oil fired / coffee husks?

Quarried stone blocks. Transport?

Deforestation Release of CO 2

Manual production of ISCEB?

The interlocks between the earth blocks reduces the need for 10+mm mortar joints as can be seen here with fired bricks

Hand made un- stabilised blocks in Eastern Chad HAT & BOOTS!

1year of weathering in exposed UK location LIME PLAIN CEMENT

6 years of weathering in UK Rammed Lime Plain Cement

Lime and cement stabilisers are normally used, but research into the use of enzymes and polymers is being conducted to provide innovative low carbon alternatives to cement. Also, there is significant research into the production of low carbon cements

Lime stabilisation: Calcium carbonate in various types of limestone are burnt and slaked to produce hydrated, hydraulic or natural-hydraulic limes (NHL). Normally, NHL is mixed with the soil to produce stabilised blocks.

Low carbon cements: In a drive to reduce the environmental impact of cement, different low carbon alternatives are being developed. These will have a dramatic effect on the amount of CO 2 used in stabilising ISSB earth blocks.

Enzymes: These are bio-molecules or proteins that will create a catalytic chemical reaction in soils to produce blocks of similar strength and durability to cement or lime stabilised blocks.

Polymers: Geopolymers are based on lumino silicates that create a chemical process to turn them into a binder that does not release CO 2, and takes place at temperatures lower than that needed for cement production. 300 kg of CO 2 per tonne is emitted, compared with 700+ kg for OPC.

Two materials are used to create a geo-polymeric cross-linking of clay soils. Sodium hydroxide, NaOH (caustic soda) is mixed with lime and a reaction takes place at low temperatures in excess of 25°c to stabilise blocks

Surface treatments: Not only can the durability of a block be improved by stabilisation, the application of various coatings will also improve them. 4:1 old engine oil/diesel mix proves very effective

Engine oil and unfinished after erosion. Plain Lime Cement

Conclusions: There is a need for a dedicated research project into different low carbon alternatives to stabilising Interlocking Stabilised Compressed Earth Blocks

‘my dad says this stabilised earth block wall has been here for 14 years’

Further details from