Algae-grown limestone could be the key to ‘carbon negative’ cement production

Limestone, the key ingredient in portland cement, could be created using a process similar to coral reef formation

By using biogenic limestone instead of quarried limestone as the filler, the cement mixture as a whole could even be considered to be ‘carbon negative’. Not only would production of the cement have a neutral effect on atmospheric CO2, the filler would actually store away CO2 extracted by the algae.