Honestly, I think we actually want a high-carbon cement: One full of graphene or other carbon compounds, pulled from the atmosphere. Per the article yesterday [1] we need to remove 2 teratonnes of CO2 from the atmosphere to meet IPCC targets. Maybe some of that will be done by taxpayer-funded carbon sequestration operations that exist only to pump the carbon 'away' in underground reserviors. But I think that if we've laid down 1 Tt of concrete, and could develop something better than that which is carbon-negative, people would be more than happy to pay for that CO2 sequestration, and that progress might actually survive an election cycle.

[1] https://spectrum.ieee.org/energy/renewables/engineers-you-ca...