For over 25 years, the ACI Foundation has hosted Technology Forums to support ACI’s expanding focus on advancing the concrete industry. These gatherings have been popular, innovation-focused educational and networking events featuring presentations by researchers, ACI committee representatives, and developers of new technologies for design, construction, and inspection. This article is the last of three articles that summarize the presentations made at the 2024 Technology Forum. These Forum presentations can be downloaded at https:// www.acifoundation.org/portals/12/Files/CIC/2024- Technology-Forum-Presentations.zip.
Reducing Embodied Carbon without Using Carbon Credits
Presented by Forrest Etter, Director, Design and Construction Innovation, Prologis, Inc.
The world’s largest industrial real estate developer, Prologis, manages distribution centers on four continents. With assets totaling 1.2 billion ft2 (111 million m2), the company is continually starting new developments. The company has committed to being net zero by 2040, which requires a 90% reduction of embodied carbon in new construction. Because concrete makes up roughly half of the carbon footprint for warehouse construction (refer to Fig. 1), concrete innovations are a major focus of the company’s decarbonization efforts. Etter described Project Nexus, a recent Prologis project (refer to Fig. 2). The company partnered with Central Concrete Supply, Whiting Turner, Bradley Concrete, and HSA Structural Engineers to create a state‐of‐the‐art, 260,000 ft2 (24,150 m2) industrial building with a 40 ft (12 m) clear height. The building, in San Leandro, CA, USA, was constructed with a global warming potential (GWP) of less than 60% of a benchmark structure, a traditional Prologis warehouse. This was achieved using an innovative structural design and three core strategies: reuse, design optimization, and low-carbon mixture design.
Big Data Trends: Outcomes of Implementing an Automatic Feedback System to Manage Slump during Delivery of Ready-Mix Concrete
Presented by Nathan Tregger, Director of Data Analytics, Verifi LLC
Over 20 million deliveries of ready mixed concrete have been monitored using onboard sensors to measure concrete properties such as slump, temperature, and age, as well as truck properties such as GPS location, mixer drum speed, and revolutions. Over a third of these deliveries have also been managed through automatic additions of either water, chemical admixtures, or both (refer to Fig. 3). Tregger reflected on outcomes of slump management, including reduced variability of delivered slump (that is, managed versus unmanaged), productivity opportunities (refer to Fig. 4), and a major potential for carbon dioxide (CO2) reduction (including an example in which a ready mixed concrete producer achieved a reduction of over 1 million lb [450,000 kg] of CO2 in a year). The ability to measure and manage every delivery generates a large quantity of data, enabling informed changes to operations and mixture designs while simultaneously reducing risk.
A Material Science-Based and Data-Driven Approach Towards Sustainable and Durable Infrastructure
Presented by Kai Gong, Assistant Professor, Rice University
Kai Gong has established the Sustainable Infrastructure Materials (SIM) group at Rice University, Houston, TX, USA. SIM focuses on critical and challenging materials science problems related to industrial decarbonization, waste encapsulation, waste-to-resources, digital fabrication, and sustainable and durable infrastructure materials. To achieve its goals, the group employs a dual strategy: a top-down approach and a bottom-up approach (refer to Fig. 5). One example was discussed for each approach. The top-down approach involves using machine learning (ML) models and inverse optimization techniques to design concrete mixtures that minimize CO2 emissions while maintaining performance. The bottom-up approach has been focused on uncovering the atomic structural fingerprint of highly complex and amorphous aluminosilicates in low-CO2 solid wastes (refer to Fig. 6). This approach has the potential to be developed into a rapid pre-screening method for assessing the suitability of waste materials for concrete production. The limitations of these methods were discussed alongside future research directions to refine these strategies and broaden their applications. Through this integrated approach, the SIM group aims to develop innovative solutions to critical challenges in sustainable infrastructure and materials science.
Reverse Engineering: The Power of Beginning with the End in Mind
Presented by Cary Kopczynski, CEO & Senior Principal, Cary Kopczynski & Company, Inc.
Reverse engineering involves optimizing a project’s construction plan before beginning detailed structural design. By first identifying efficient construction strategies, unnecessary design complexity can be eliminated, innovation stimulated, and constructability improved. The improved constructability of design leads to improved productivity of construction, which is the mission of PRO: An ACI Center of Excellence for Advancing Productivity (refer to Fig. 7). Kopczynski elaborated on these concepts using successful project case histories (refer to Fig. 8), and he explained how PRO is engaging with the concrete industry to stimulate innovation and efficiency.
Revolutionizing Concrete Production with AI: Bridging the Gap Between Innovation and Application
Presented by Andrew Fahim, Research & Development Engineer, Giatec Scientific Inc.
Giatec builds and trains models based on artificial neural networks, using a data set representing 75 million m3 (2.6 million ft3) of concrete produced by 1500 plants (refer to Fig. 9). The data set includes 300,000 unique mixtures, 2000 raw materials, and over 100 test methods, and it has been used to create models with predictive capabilities for in-transit, fresh, and hardened properties. The data of immediate value include proportions, material types and sources, performance, specifications, and delivery information. Using this expertise, Giatec is building what they call SmartMix—a platform that allows them to collect data from ready mixed concrete producers and identify opportunities for optimization. Data are collected from batching systems, in-transit systems, and jobsite tests, and the platform’s algorithms generate options within seconds (refer to Fig. 10). If a producer accepts the optimizations, the revision is automatically pushed to the batching system. This is true mixture management rather than mixture maintenance.
NTeC-C, Carbon Nanotube Reinforcing Additives for Concrete
Presented by Ricardo Prada Silvy, Chief Technology Officer, Chasm Advanced Materials
CHASM’s scalable and cost effective NTeC®‐C carbon nanotubes (CNT) technology leverages low-cost hydrocarbon feedstock to co-produce clean hydrogen and high-value carbon products. Despite the proven potential of CNT technology to enhance concrete strength, adoption has been hindered by high costs associated with traditional production methods as well as ineffective dispersion of CNTs in concrete mixtures. CHASM’s NTeC® solution overcomes these barriers with a CAPEX-efficient rotary kiln process that synthesizes CNT hybrids on cement-compatible particles, ensuring seamless dispersion during hydration (refer to Fig. 11). The synthesis methods result in various products, including self-dispensing CNT granules (refer to Fig. 12) and cement powder with pre-deposited CNTs. NTeC CNTs significantly enhance concrete performance by boosting flexural strength, improving early and 28-day strengths, and reducing cracking and permeability.