Strategic Issues in Building Materials Production II: Cement and Concrete Concrete is an ancient building material, used by the Romans for many of their great roads, buildings and aqueducts. But, except for perhaps the steel used for modern skyscrapers, no other material has so personified the industrial-era built environment as has concretewith artists and musicians assailing the twentieth century capitalist city as a concrete jungle. Concrete is the most widely used construction material in the world, with Canadians using about 10 kg per person per day (Ridsdale, 1998). One might justifiably expect that the evolving green building movement would, at very least, have to come to terms withand redefine the use ofthis omnipresent material. More generally, alternatives to the concrete jungle cover the wide range of green materialsand relationshipscovered in this dissertation. This section, however, will survey more specific alternatives to concrete use, as well as some the ways that concrete itself is being transformed to become a more ecological material.