Conference on concrete and sustainability at MIT

Producing concrete is energy-intensive and account for 5 to 10 percent of annual emmisions of CO2. Making manufacuring process of concetre more effecient or making concrete more durable so less of it is needed coule have far-reaching environmental repercussion. "Could we make a concrete sidewalk that never cracks?"asked Krystyn Van Vliet, associate professor of materials science and engineering at MIT.
An article from Boston Globe, August 8, 2011.

How is ready mix concrete a green building material?

There's two things that concrete is good at. Lasting a long time, and storing a reasonable amount of thermal heat. --an answer from gogreenliving.org.

MIT’s New Concrete Formula Could Cut Carbon Emissions by Half -- Jetson Green

Carbon Negative Cement Wins Green Award

“If implemented, the material would take care of most of construction’s attempts at carbon reductions in one fell swoop,” says Material ConneXion Vice President Dr. Andrew H. Dent of the company’s selection for 2011 MEDIUM award. The selection, Novacem‘s Carbon Negative Cemement, replaces calcium carbonates used in typical cement formulation with magnesium silicates and uses a lower-temperature production process that runs on biomass fuels.

Typical cement is responsible for approximately 5 percent of man-made carbon dioxide; the emissions are caused by the processing of limestone and raw materials and the burning of fossil fuels. -- ArchDaily

glass cullet

Glass cullet is what all your recycled bottles become: pieces of glass smaller than 19mm but larger than .075 mm, $300-500/ton depending on colour, composition (borosylicate lab glass for example) and destination – glass production, landscape material or aggregate.

Concretes made with green glass cullet aggregate have been found to be stronger, attributed to better bonding with the cement – this reported in the Magazine of Concrete Research in 2004.  And while it seems that glass cullet concrete is used for lots of rough applications such as roadbeds and fill, as an aggregate in concrete it increases the strength and insulation value, glass having better thermal qualities that other aggregates. -- onsite