Field demonstrations are essential for evaluating the performance of pozzolans in concrete under real-world conditions, providing valuable insights into both constructability and long-term durability. As we explore the use of supplementary cementitious materials (SCMs) beyond traditional coal fly ash and slag—such as natural pozzolans, calcined clays, and biomass ashes—it becomes especially important to recognize that these materials have different properties and behaviors that must be understood in the field. While laboratory tests offer controlled data, field trials reveal how these alternative SCMs interact with local aggregates, water, climate, and construction practices, making them a critical step in validating lab findings. These demonstrations allow stakeholders to monitor workability, setting time, finishing characteristics, and curing behavior, while also tracking durability indicators such as cracking, permeability, and strength development over time. Ultimately, field demonstrations build confidence in the use of alternative SCMs by demonstrating their practical viability and ensuring that sustainability goals are met without compromising performance.
Learning Objectives:
(1) Evaluate constructability workability finishing and curing requriements;
(2) Assess Field Durability Indicators Monitor and interpret field-based durability indicators such as cracking, permeability, and strength development over time to evaluate the long-term performance of concrete with alternative SCMs;
(3) Compare SCM Performance in Field vs. Lab Analyze how alternative SCMs behave differently in field conditions compared to lab settings, considering interactions with local materials and environmental factors;
(4) Showcase and highlight the importance of demonstration projects.
Evolution and Deployment of Type IT/CEM II-C Cements in the US and Europe: An Opportunity for Calcined Clays
Presented By: Franco Zunino
Affiliation: UC Berkeley
Description: The adoption of blended cements with high substitution levels in the US and Europe have emerged as a promising strategy to mitigate carbon emissions while in many cases enabling to increase local production of materials, reducing the reliance on imports. In this presentation, the status of technological deployment of highly substituted Type IT / CEM II-C cement will be discussed, with emphasis on outstanding challenges. The role of calcined clays to formulate highly reactive systems like LC3 will be highlighted as a key technology that enables preserving mechanical performance and enhancing durability for highly demanding applications.
Development of LC3-Like Blends Using US Regional Materials
Presented By: Kimberly Kurtis
Affiliation: Georgia Institute of Technology
Description: LC3-like binder systems were formulated by blending commercially available materials in four different US regions. Type IL cements were blended with natural pozzolans, including calcined clay (CC), and, in some mixtures, additional limestone powder (L); Type IP cement was blended with limestone powder. Regional blends incorporated 20–30% calcined clay and up to 15% limestone powder. All blends met ASTM C595 strength requirements, with 30% calcined clay mixtures achieving compressive, splitting tensile, and flexural strengths comparable to or exceeding neat cement controls. Surface resistivity was significantly increased by calcined clay and further enhanced by limestone addition, indicating improved durability. Freeze-thaw resistance remained comparable to conventional mixes, and initial sorptivity was reduced, supporting enhanced resistance to transport-related deterioration. Machine learning models, trained on over 1600 mixtures, enabled rapid optimization of blend proportions and sulfate balance, supporting reliable performance across regional sources. Field trials confirmed constructability and compliance with specification requirements. These results demonstrate that LC3-like blends using US regional materials can deliver robust mechanical and durability performance, supporting broader adoption of sustainable, low-clinker concrete technologies.
That’s Hot! Calcined Clay Use in Thermally Controlled Concrete Placements
Presented By: Kyle Riding
Affiliation: University of Florida
Description: Calcined clay has been widely discussed as a new supplementary cementitious material that can be made from industrial waste materials in many parts of the world. In order for ready-mixed concrete producers to adopt calcined clay for use in their plants and devote precious silo space for this material, it should be able to be used in most construction applications including mass and thermally controlled concrete placements. This presentation will discuss how calcined clay and calcined clay-limestone blended cement systems impact the cementitious system temperature sensitivity, concrete heat rise, and strategies for using calcined clay in thermally controlled concrete placements.
Mechanochemical Activation of Clays
Presented By: Maria Juenger
Affiliation: University of Texas at Austin
Description: This presentation will explore mechanochemical activation as a method to enhance the reactivity of clays for use as SCMs. The process parameters, characterization techniques, and performance outcomes in cementitious systems will be discussed, with emphasis on the potential of activated clays as sustainable alternatives to conventional binders.
A Universal Approach for ASR Prevention for a Range of Cementitious Systems Including LC3
Presented By: Jason Ideker
Affiliation: Oregon State University
Description: A new approach for alkali-silica reaction prevention has been developed which combines the alkali sensitivity of the aggregate with the available alkali from the cementitious blend. The alkali sensitivity or alkali threshold of an aggregate is measured using a modified AASHTO T380 test method run for 126 days and using a range of pore solution alkalinities that are matched to the cementitious materials pore solution composition. Typical alkali thresholds for the aggregates are between 1.5 to 3 kg/m3. The available alkali from the entire cementitious blend (e.g. LC3, or PLC, or PLC + SCM, and more) is determined from a new test method that was loosely adapted from the ASTM C311 available alkali method. In this method a 0.5 w/cm paste is cured for 28 days at 38 C. Then it is crushed, finely ground, exposed to a simulated pore solution for three days, and the available alkali is determined from the increase in alkalinity to that simulated pore solution over a three-day period. If the alkali threshold of the aggregate is greater than the available alkali from the cementitious blend there is a low risk of deleterious ASR. Laboratory results will be presented for a wide range of aggregate reactivities (R1-R3 according to ASTM C1778) and cementitious blends (LC3, natural pozzolans, blended SCMs, fly ash, slag, ground glass, PLC and OPC). Further, this is being confirmed in new outdoor exposure blocks placed into eight sites across North America. While data from those sites is not yet available the importance of outdoor exposure site testing for benchmarking new materials will be presented.