FIBROUS CONCRETE

The basic idea that initiates this project is the way paper fibres hold Portland cement or perhaps the Portland cement adheres to paper fibres. When the water is added to paper and Portland cement drains from the mix, it comes out almost completely clear. There is no messy and Eco-unfriendly cement sediment left on the ground, running into waterways etc., papercrete can be produced using solar energy.

Papercrete matrix

Paper is principally wood cellulose. Cellulose is natural polymer. And Fig shows the links of cellulose bonds. The cellulose chain bristles with polar-OH groups. These groups form hydrogen bonds with -OH group on adjacent chains, bundling, the chain together. The chains also pack regularly in places to form hard, stable crystalline region that give the bundled chains even more stability and strength. This hydrogen bonding forms the basics of papercrete’s strength.  Fig shows the network of cellulose fibres and smaller offshoots from the fibres called fibrils. Fig   shows the papercrete matrix. In this, fibres and fibrils network forms a matrix, which becomes coated with Portland cement. When these networks of fibers and fibrils dry, they inter wine and cling together with the power of hydrogen bond. Coating this fiber with Portland cement creates a cement matrix, which encases the fibers for extra strength. Of course paper has more in it than cellulose.  Raw cellulose has comparatively rough texture. Clay, fly ash is added to make the cellulose very smooth. The great thing about the generic papercrete is how it traps air. When the water drains out and evaporates, it leaves the thousands of tiny air pockets. This is what makes the material light and good insulator.

          While adding more sand or glass to the mix results in a denser, stronger, more flame retardant material, but adds weight and reduces R- value. Heavy mixes with added sand, glass etc., increases strength and resistance to abrasion, but also reduces flexibility somewhat, adds weight and may reduce R-value. So the trick is finding the best mix for the application.