Argos USA announced this week that its integrated Roberta plant in Alabama is set to produce 100% Portland limestone cement (PLC) by June 2022. As part of the transition three of its terminals in North Carolina will also switch over at the same time. The company also expects that all of its plants will convert to PLC in 2023. Cement sites including Newberry in Florida, Harleyville in South Carolina and Martinsburg in West Virginia are already producing PLC.
The change by Argos marks the latest example in an ongoing trend of US-based cement companies moving entire plants to PLC production. In September 2021 LafargeHolcim US said that its integrated Midlothian plant in Texas was preparing to convert to full PLC production and that it would be the first plant in the US to do so. It later confirmed that the plant had done so by the end of 2021. In October 2021 GCC said that its Trident Plant in Montana would fully move to PLC in early 2022. Then in November 2021 Titan America said that its Pennsuco cement plant in Florida would make the change possibly by 2023. Moving into 2022 brought the news that LafargeHolcim US’ Ste. Genevieve plant in Missouri and its Alpena plant in Michigan had each transitioned to PLC production. Lehigh Hanson then rounded up the bunch earlier this month, at the start of February 2022, when it announced that a PLC was the primary product now coming out of its Mason City plant in Iowa. It even invited a US Member of Congress to celebrate!
The current expansionist phase of PLC usage in the US dates back to late 2020 when the Portland Cement Association (PCA) launched a dedicated website to promote the use of the blended cement by discussing its applications and benefits. It then released a new environmental product declaration in March 2021 and PLC received a mention in the PCA’s Roadmap to Carbon Neutrality when it was released a year later in October 2021. Lots of work went into PLC prior to 2020 though, both by the PCA and others. The first commercial production of PLC in the US started in 2005 and PLC gained its own blended cement specification in 2012. Notably, the PCA has been tracking the state acceptance of PLC by the Department of Transportation and it grew markedly during the 2010s.
The US is playing catch-up with PLC. In Europe its usage dates back to the 1960s. Cembureau, the European Cement Association, reported usage of around 30% in 2004. More recently in 2020, the VDZ, the German Cement Association, reported a similar figure domestically with the proportion of blended cement shipments including limestone, shale and multiple additives at 31.6%. In the US it is hard to gauge the scale of the current move towards PLC by producers, due to limited publicly available data. A PCA survey reported PLC production of 0.89Mt in 2016. If all the plants mentioned above convert fully to PLC and maintain their rated production capacity that would be something like 14Mt/yr of PLC in 2023 or 11% of the US’s total cement capacity. For comparison, the United States Geological Survey (USGS) reported total shipments of all blended cements at 3.3Mt in 2020 and a total of 5.4Mt for the first 11 months of 2021. Plus, remember that PLC is just one blended cement among others, like those that use slag or fly ash.
Recent developments show that a large change is coming towards the US cement market in the update of blended cements. It’s been a long time coming but the last six months have seen brisk increases in PLC production at scale. The exact data is not available but one might expect something around triple the current number of production plants making PLC if the US market heads towards European levels. This rough estimate doesn’t take into account existing partial PLC production levels. At the same time the US cement sector should see a fall in its emissions due to PLC’s 10% reduction in CO2 emissions compared to ordinary Portland cement
