Description

With the recent fundamental shift towards building more sustainable infrastructure, the use of blended cement to lower the embodied carbon of concrete has grown rapidly. In 2021, blended cement represented approximately 3% of the 100 million metric tons of cement consumed annually in the United States. Between 2021 and 2024, the share of blended cement grew to more than 60% of total U.S. cement consumption.

Blended cements are produced by intimately and uniformly inter-grinding or blending two or more types of fine materials. Manufactured to meet ASTM C595/C595M, the primary materials are portland cement or portland cement clinker, limestone, slag cement, fly ash, silica fume, calcined clay, and other pozzolans. Blended cements can also capitalize on performance and durability benefits of supplementary cementitious materials (SCMs) that have been demonstrated for well over 80 years.

For both fresh and hardened concrete properties, concrete mixtures formulated with blended cements can perform similarly to those formulated with traditional portland cement. Maintaining concrete behavior requires additional trial batching as when changing from one source of material to another. This webinar will include discussion of best pre-construction practices when transitioning projects to blended cements, including Type IL and other ASTM C595 blended cements including Type IS (slag), Type IP (pozzolan), and Type IT (ternary).

The majority of blended cement consumed in the U.S. is currently portland-limestone cement (PLC), or Type IL. PLC contains more than 5% but less than or equal to 15% by mass of finely ground limestone as an ingredient. There are several examples of dam projects in the U.S. that incorporated PLC. In this webinar, case histories will be discussed for recent projects that used PLC for mass concrete and geotechnical applications including anchoring and foundation grouting