Lightweight extruded cementitious material and method of making the same

摘要

Embodiments of the present disclosure are directed to a low density monolithic fiber cement article that incorporates controlled air entrainment evenly distributed throughout the article to improve various physical properties of the article. In some implementations, air entrainment agents are used to create voids in the article, thereby lowering the density and weight of the boards while maintaining adequate strength. In some implementations, the air entrainment agents can be added in solution to create a foam, or can be used to generate a pre-foam, which can be added to a cementitious paste. The cementitious paste incorporating the air entrainment agent can proceed through an extrusion process, experiencing high pressures, where the voids remain in the final monolithic fiber cement board.

主权项

1. A low density cementitious article comprising:
a monolithic cementitious matrix comprising a plurality of closed cell voids, wherein the size and shape of the closed cell voids are defined by the cementitious matrix; said closed cell voids are distributed throughout the matrix in a manner such that the density of the cementitious matrix remains uniform throughout the article, wherein the cementitious matrix has a density of greater than or equal to at least 0.5 g/cm3 and less than 1 g/cm3, wherein the composition of the cementitious matrix comprises 35-70% cement; 0-15% reinforcing fibers; 0-0.1% air entrainment agents; 10-70% siliceous aggregates; and 0.6-1% viscosity enhancement agents, wherein said closed cell voids are distributed so that there are between 25 and 2000 voids per cm3.