Loose materials - The Ecology of Building Materials - page 139

Recycling must also be considered, since the energy consumption in manufac-
ture is so high. The durability of fired clay products is very high, and the energy
needed to remove and clean up old material only represents 0.5 per cent of the
energy required for the manufacture of bricks and tiles. However, the re-use of
bricks is only possible if a weak- or medium-strength mortar has been used.
Products such as roof tiles which have no mortared joints, have a very high re-
usability potential. Bricks can also be ground to pozzolana powder, if they were
originally fired at temperatures no higher than 600°C.
Light expanded clay that is free from mortar, e.g. in capillary beds or in insu-
lation underneath a building, can be easily re-used in the same way if it has been
protected from roots, sand and earth.

References

A SFAG H et al , Pilot plant expanded clay aggregates ,
Engineering News No. 17, Lahore 1972
B RIEN K et al , Zytan - a new building material , Bahia
1978
B ROCH T, Larebog: bygningskunsten , Christiania 1848
K HALILI N, Racing alone , San Francisco 1983

L ÅG J, Berggrunn, jord og jordsmonn , Oslo 1979
P ARRY J P M, The brick industry: Energy conserva-
tion and scale of operation , Appr. Techn . Vol. 2
1975
S PENCE R J S, Small scale building materials produc-
tion in India , unpublished, Cambridge 1974