ACPA Concrete Pavement Progress - Quarter 3, 2021

A L A B A M A I N T E R S T A T E EcoCemPLC is a portland limestone cement (PLC) approved in the AASHTO M-240 and ASTMC595 standards as a Type IL. It is produced using ordinary portland clinker ground with limestone. Compared to ASTM C150 and AAS- HTOM85 Type I portland cement, EcoCemPLC contains as much as 10% more limestone using the same components and yieldswith equivalent performance to ordinary portland cement. Using innovative technology to increase the amount of limestone and decrease the amount of clinker reduces both the energy required to produce the cement and associated emissions, making it a greener alternative compared to traditional portland cement mixes. “Prior to this project, the materials and testing lab inMontgomery had performed testing alongside traditional Type I-II cement to confirm effective- ness,” explainsDewayneEhlers,materials and tests engineer for the Birmingham Area for ALDOT. Durable Delivery Ultimately, A.G. Peltz placedmore than 128,000 sq yds of 5-in. RCC on shoulders ranging from 5 ft. (inside) to 10 ft. (outside) along the nearly 8-mile stretch of roadway. On the I-59 project, A.G. Peltz was able to reduce the concrete carbon footprint by about 10% or about 550 tons. The I-59 project is ALDOT’s second foray with RCC on a travel lane. The first was the McAshan Road project, also performed by A.G. Peltz Group in 2018. For theMcAshan project, the contractor placed 9,727 sq yds forALDOTonMcAshanRoad in McCalla. At the time, ALDOT was looking for a high structural value pavement that could withstand heavy loads and still allow interrupted access. RCC proved the right answer. In this case, the contractor placed 10-in. RCC in one lift. If all cement used in the U.S. in 2019 had been converted to PLC, carbon dioxide emissions would have been reduced by 8.1 million metric tons, which the U.S. EPA says is the equivalent of taking 1.75 million cars off the road for an entire year. 1 ALDOT, along with at least 32 other DOTs, allow the use of PLC in its concrete specifications. “We see the addition of lower carbon alternatives such as PLC as a great option for the future work, particularlywith growing use of RCC,” adds Gray. The I-59 project was completed in early Fall 2021. ALDOT also initiated a second concurrent project for another sevenmiles of shoulder work on I-59 in St. Clair County. This highway, which averages 30,000 vehicles per day, will also use the same RCC design on the shoulders with portland limestone cement, adding another 160,000 sq yds of environmentally-friendly concrete. When asked about the overall opinion about the project, Ehlers says that after a number of trips to evaluate the pavement, it appears to be performing well. “What we’ve seen so far is that it is pretty durable and gives a good presence.” Lori Tiefenthaler is senior director of marketing for Lehigh Hanson, Inc. Photo by Lehigh Hanson/Audrey K. Noe www.acpa.org Quarter 3, 2021 11 1. Portland-Limestone Cement and Sustainability. Portland Cement Association. www.cement.org/sustainability/portland-limestone-cement Want to learn more about RCC? See related article on page 24.