There are a number of sustainable building techniques that predate the high-tech industrial design strategies getting so much attention today. Strawbale, cob, rammed earth and adobe aren't the first thing to come to mind any more when we talk about "sustainable building" -- in fact, they conjure just the earthen back-to-the-land stereotype that green builders now combat with their modern, elegant buildings.
But working with natural materials is not a lost art, and by infusing the advantages of technology into the manufacturing process, we can end up with great materials like kirei and Grancrete. And at the Ashland School of Environmental Technology, there's a new project underway to develop Strawjet -- a load-bearing, insulating structural material made from straw and other fibrous agricultural byproducts. The way this material distinguishes itself is that it binds whole organic material, rather than a composite of waste pulp.
The desire to use straw as a building material is as old as the agricultural revolution, but straw based products have always suffered from the apparent lack of strength of the plant itself. Previous technologies from straw bale construction to the recent development of compressed straw-board and straw panels have all begun with crushed, chopped straw. The fundamental advance embodied in the Strawjet technology is the use of the whole undamaged plant stem. The compressive strength of straw when loaded parallel with the stem is impressive...The StrawJet harvests straw in the field before it has been crushed or damaged, orients the stems so they are all parallel, adds a clay based binding material, compresses the bundle and binds it into a continuous length of 2 inch cable using a polyester yarn. Once the clay has dried, the cable becomes a rigid cylinder.
The project leaders purport that the significance of the technology is in cost savings over other green building materials due to the straw being a waste product; structural integrity great enough to withstand earhtquakes; and supposedly the promise of significant carbon sequestration over the course of the building's lifecycle.
There's a great deal more information on the process and the product at the project website.
