Compressed Earth Brick
Compressed earth block are unfired bricks. When you fire clay in the kiln you bake the clay and transform it into an unbreathable material with very little thermal mass. Unfired bricks keep their alternative properties of maintaining and regulating heat and air, so the important difference between fired and unfired bricks is that fired bricks help keep the building cool in summer and warm in winter whilst fired bricks remain at a constant temperature throughout the year.
Compressed earth blocks are made up of clay, earth, aggregate mixed together and then machine pressed into a solid block, squeezing out all of the water, to leave a very uniform and regular sized block. As the water has been squeezed out of the block, little drying time is needed for these blocks and some machines allow the bricks to go directly from the press to the wall, completely eliminating the drying time required.
This sort of building has been very prevalent across the southern states of North America such as New Mexico, Arizona and California and has also been used a lot in developing countries as materials can be sourced locally. Brick presses can produce between 800 and 5000 bricks a day, enough bricks to be built in one day.
The Global Village Construction Set have released plans for an high performance open source build-yourself earth brick press that can produce 5,000 bricks a day – http://opensourceecology.org/wiki/Civilization_Starter_Kit_DVD_v0.01#CEB_Press