Rammed Earth
From Swikipedia
Introduction
Rammed Earth is a wall-building technique, by which a certain mixture of mud, chalk, lime, gravel and water, is very forcibly tamped inside formwork. The resulting wall has high mass, so it works well in hot climates. It often needs no exterior or interior covering, thus saving materials.
Brief Description
It is an ancient building method that has seen a revival in recent years as people seek more sustainable building materials and natural building methods. Because of the nature of the materials used it is incombustible, thermally insulating and very strong and hardwearing. It also has the added advantage of being a simple way to construct walls. Traditionally, rammed earth buildings are common in arid regions where wood is in scarce supply.
Benefits of Rammed Earth Structures:
As rammed earth structures utilize locally available materials, they typically have a low embodied energy rating and generate very little waste, thus resulting in energy efficient buildings.
Earth used for building is a widely-available resource and harvesting it for use in construction has minimal environmental impact.
The soils used are typically sub-soils, retaining organic topsoil for agricultural use. Also, if soil from the site where the construction takes place is used, it further reduces the cost and energy used for transportation.
The materials are often inexpensive or free, making it highly affordable and a viable building material for low-income builders. Today more than 30 percent of the world's population uses earth as a building material.
Rammed earth can carry a heavy load and using re-bar, wood or bamboo reinforcement can prevent failure caused by earthquakes or heavy storms.
Termites will not infest rammed earth walls and the material is reusable, biodegradable and highly fire resistant.
It provides good thermal mass, which implies good heat storage and absorption. This results in keeping indoor temperatures stable.
It also controls humidity where walls contain clay which is exposed to an internal space.
Thus, rammed earth structures are not only a cost effective and viable construction technique, but also an environment friendly option.
An Example:
A few kilometres away from the Banasura Sagar Dam, in rugged hilly terrain in Wayanad, stands the Banasura Hill Resort, touted to be the biggest earth resort in India. The rammed earth walls of the resort are built with mud from the very site that it stands on. Earth scooped out from the hill slope to create a plain was used to build the resort. Local tribals were called in for the labour and their expertise in building with mud was also tapped. This is an excellent example of a rammed earth structure in India.
References:
http://en.wikipedia.org/wiki/Rammed_earth
http://www.eartharchitecture.org/index.php?/categories/28-India
