Abstract: A method of bonding aggregates with resinous binder compositions to produce building materials of controlled strength, porosity and weight. Two types of building materials are made with this bonding method; one is a controlled strength, waterproof material, and the other is a controlled strength, porous material. The method employs either a phenolic resin binder composition in a semi-clear liquid form to maintain the natural coloration of the aggregate, or a furan resin binder composition which discolors the aggregate to a black or dark brown tone. In the controlled strength, waterproof product, the aggregate is gradated to provide a mixture of various particle sizes, including dust and fines, so that all the voids in the resulting product are filled. In the controlled strength porous product, the aggregate is gradated to provide a mixture of various particle sizes, excluding dust and fines, so voids in the product remain open, allowing moisture to pass through the product.

Abstract: A machine for mixing a resinous binder compound with aggregates on a continuous flow basis to produce a building material or the like, without the use of cement or water. Aggregate is fed into a first mixing chamber where a metered amount of resin binder composition is added thereto. The mixture is then passed into a first rotating mixing tube having a rotating mixing screw conveyor therein with triangular teeth between the convolutions of the screw. The outer tube rotates contra to the direction of the inner screw which produces a thorough mixing action, coating each particle of the aggregate with the resin binder composition. This mixture is then fed into a second mixing chamber where a metered amount of a second resin binder composition is mixed with the aggregate. A second mixing tube, also having a rotating mixing screw conveyor and triangular teeth, then thoroughly mixes the blend. The resultant aggregate product is then conveyed to a discharge spout.