Rammed Earth Construction

It is the soil-based ancient method of construction in which the continuous walls are built by placing correct proportions of damp or moist sub soils(Optimum moisture content:8%～12% of dry weight)consisting of clay/silt(15%～25%),sand(50%～60%)and gravel(15%～20%)with or without stabilizers like cement(around 5%)in thin layers of about 100 mm to 150 mm into the temporary formwork and are compacted by hand or pneumatic tampers to the sufficient wall strength(Figure 1)[3].The quality of soil,proper proportion of mixed ingredients,type of stabilizers,amount of water,effective/adequate compaction and curing are some of the essential criteria for good quality rammed earth construction.

Generally,there are two types of rammed earth construction,i.e.stabilized and unstabilized rammed earth.Unstabilized rammed earth is made from clay,silt,sand,and gravel,whereas stabilized rammed earth contains additives like cement or lime.

Figure 1　Rammed earth construction procedure