Concrete consists of three parts: water, an aggregate such as sand or gravel, and a cement which binds everything together. The cement is the part that typically takes about a month to cure after being poured. And a slow curing time isn't cement's only problem.

Traditional Portland-style cement is made by grinding up limestone and other raw materials, then heating the resulting powder to temperatures of up to 1,450 ºC (2,642 ºF). Unfortunately, the processes by which that heat is generated produce a lot of carbon dioxide.

What's more, as the heated limestone forms into cement via a process known as calcination, it releases trapped carbon dioxide as a byproduct. The combination of that CO2 and the CO2 produced in the heat-generating process is estimated to be responsible for 5% to 8% of all human-caused greenhouse gas emissions.