Replacing OPC with PLC
What is PLC? Portland-limestone cement (PLC) is engineered with a higher limestone content than ordinary portland cement (OPC). It performs just like the cement you’re used to using — follows the same specifications and the same mix design. However, with PLC, you benefit from a lower carbon profile – by about 10 percent.
Almost anywhere you use ordinary OPC, you can use PLC instead. In the U.S., PLCs have an established track record for use in transportation infrastructure. Many states have been placing PLC concrete pavements for more than a decade – from highways and bridges to buildings. PLC has also been used around the world for decades and has been subjected to years of research and testing by cement manufacturers, ready-mix concrete producers and specifying agencies, as well as owners and end users.
The advantages of PLC beyond its reduction in the carbon profile is that it is a 1:1 cement replacement. Additionally, concrete made with PLC has excellent placing and finishing properties. Some contractors even report that PLC concrete finishes and pumps slightly better than OPC concrete.
How accepted is it? PLC (Type IL) is permitted by ACI 318, Building Code Requirements for Structural Concrete; ACI 301, Specification for Structural Concrete; ASTM C94, Specification for Ready Mixed Concrete; and by the AIA MasterSpec.
Architects and other designers who are tasked with meeting goals by green rating systems or codes will find PLC a useful approach to lower carbon footprint for any project.