The May 12th Lunch & Learn was held at the DoubleTree by Hilton Sacrament in Sacramento.
David Imse, left, and Chapter Vice President and Program Chair Jim Ayala.
The afternoon's guest speaker was David J. Imse, P.E., a Technical Sales Engineer with Nevada Cement Company, bringing over 30 years of experience in the cement and concrete industry. He specializes in construction materials and provides leadership across sales, technical services, product development, and marketing. A graduate of Marquette University with a B.S. in Civil Engineering, David is a Registered Professional Engineer and an active member of NSPE, ASTM, and ACI.
The presentation was a discussion about environmental challenges and innovations in the cement and concrete industry, focusing particularly on California. The speaker addressed the significant role of cement plants in global CO2 emissions, with calcium (from limestone) being the largest contributor. While carbon capture was considered, the presentation emphasized reducing Portland cement in concrete mixes as a key strategy for lowering emissions.
The presentation was structured around four main sections: the urgency of action ("why now, why here"), technical fundamentals related to natural pozzolans, Environmental Product Declarations (EPDs), and performance-based mix designs developed at Nevada Cement. Traditional supplementary cementitious materials (SCMs), such as fly ash and slag, are declining due to environmental concerns and market changes. As coal-burning power plants and blast furnaces are phased out, these once "green" materials are becoming less available because of their association with pollution.
California’s cement market was discussed in detail, highlighting the shift to blended cements like Type 1L (with added limestone) and the challenges of adoption due to market forces, competition, and regulatory requirements. The presentation explained that market pressure, rather than producer preference, determines the prevalence of certain cement types. Regions with fewer options, like Utah, have nearly universal adoption of blended products, while competitive markets like California see less uptake.
Natural pozzolans, particularly volcanic rocks sourced locally, were presented as a promising alternative. The speaker described their geological origins and performance benefits, including improved strength, permeability, and density in concrete. New test methods, such as the R3 bound water test, were introduced to better assess pozzolan activity and reliability compared to traditional strength activity indices.
The environmental impact of various mix designs was evaluated using global warming potential and lifecycle assessments. Locally sourced natural pozzolans were shown to offer significant reductions in carbon footprint compared to imported materials, especially when transportation emissions are considered. The presentation also emphasized the importance of optimizing particle size distributions for better performance and highlighted ongoing research and factory tests aimed at improving blended cement products.
In closing, the speaker likened the modern natural pozzolan products to a "new and improved" version, not like "your father's" cement, and encouraged continued progress in California’s sustainable concrete practices. The presentation ended with a discussion on the economic and regulatory factors influencing the use of natural pozzolans, noting their cost-effectiveness and ease of production compared to processed SCMs like slag and fly ash.
Attendees enjoyed a delicious lunch and a timely presentation.
The Chapter would like to thank the DoubleTree by Hilton staff, guest speaker David Imse, and all those in attendance for making this a sucessful and enjoyable afternoon.