Decoupling of Concrete Production from Embodied Carbon Emissions through Nanotechnology, Part 2 of 2

Wednesday, November 6, 2024  11:00 AM - 1:00 PM, Grand BR Salon A

Nanotechnology has the potential to enable efficient decarbonization pathways in nullifying the greenhouse gas (GHG) emissions in concrete industry. This session provides a unique opportunity for engineers, scientists, and industry leaders to learn and experience recent research advances on the design of carbon sequestration-efficient engineered concrete materials and technologies targeting zero or negative net CO2 emissions in civil infrastructure.

Learning Objectives:
(1) Report recent progress about the use of nanomaterials in enabling enhanced CO2 capture and mineralization process in concrete;
(2) Summarize recent advances about the development of nanomaterial admixtures for reducing the carbon footprint of concrete manufacturing;
(3) Identify best practices for controlling the chemical interactions in nanoscale interfaces of engineered cementitious systems;
(4) Review recent challenges associated with the sustainability of carbonated nanomodified concrete.

Engineering the Carbonation Kinetic Rates of Concrete for Active CO2 Sequestration: Ef-fects of 1D and 2D Carbon-Based Nanomaterials

Presented By: Maria Konsta
Affiliation: University of Texas at Arlington
Description: In this presentation, we demonstrate an effective way to enhance the CO2 capture and minerali-zation capacity of concrete by controlling the carbonation kinetics within the cementitious matrix using 1D and 2D carbon-based nanomaterials. When added in a cementitious system, carbon-based nanomaterials provide a unique platform for enhancing the interactions between CO2 and C-S-H due to the ultra-high surface area, essential for surface chemistry. Compared to the CNTs, graphene engineered concrete exhibits a 50% higher CO2 sequestration capacity, due to the 2x higher specific surface area of the 2D GNPs.

Nanomodification of Cement Paste’s Microstructure and Pore Structure: Acceleration of Natural CO2 Capture of Hardened Cementitious Composites

Presented By: Marina Lopez-Arias
Affiliation: Purdue University - West Lafayette
Description: This talk will summarize our latest advances in understanding the effects of nanoparticles' addi-tion in cement pastes, particularly its interaction with CO2 throughout the materials' service life. Additionally, it will cover current and novel methods for quantifying CO2 uptake in cementitious materials, along with exploring various potential mechanisms for enhancing CO2 uptake through the use of nano-additives.

Carbon Sequestration Capacity of OPC Concrete Using Surface-Treated Recycled Aggregates and Nanomaterials

Presented By: Myrsini Maglogianni
Affiliation: Wayne State University
Description: In this presentation the CO2 uptake and mineralization potential of OPC Concrete with surface-treated recycled aggregates and nano-TiO2 are demonstrated. Accelerated carbon curing was per-formed to evaluate the synergistic effect between surface-treated recycled concrete aggregates and nano-TiO2 on CO2 sequestration. Thermogravimetric analysis results showed that addition of nano-TiO2 increased the CaCO3 amount formed within the cementitious matrix. The findings indicate a higher CO2 uptake and mineralization capacity of the nanomodified concrete compared to the OPC concrete.

Mitigating Embodied Carbon Emissions in Air-Entrained Concrete through Polymeric Microspheres

Presented By: Rui He
Affiliation: Lyles School of Civil Engineering, Purdue Universi
Description: Concrete durability in freezing-thawing conditions relies significantly on the entrained air con-tent, with a conventional guideline indicating that 1% entrained air leads to a 5% reduction in compressive strength. An air content range of 5% to 8% is typically recommended to protect concrete from freezing-thawing damage. Consequently, achieving a freezing-thawing resistance concrete with an entrapped air content of 2.5% necessitates a range of 2.5% to 5.5% entrained air, resulting in a substantial 12.5% to 27.5% compression strength reduction. Addressing this strength loss requires additional cement, which consequently increases the embodied carbon footprint of the concrete industry. In this study, we introduce polymeric microspheres as a means of entraining air into concrete, aiming to fulfill freezing-thawing resistance requirements without compromising strength. We compare the carbon footprint of concrete exhibiting similar performance when using air-entraining agents (AEA) versus microspheres. Additionally, we in-vestigate the microstructure, mechanical strength, and chloride ion resistance properties of these concrete formulations. Our findings offer insights into sustainable strategies for enhancing con-crete durability while mitigating environmental impacts in construction practices.

Chemically Induced Pre-Cure Carbonation: A Novel System for Carbon Sequestration in Cementitious Materials

Presented By: Marcin Hajduczek
Affiliation: Massachusetts Institute of Technology
Description: To address growing concerns over concrete's environmental impact, we propose a novel frame-work to store CO2 in cementitious materials through chemically induced pre-cure carbonation, whereby carbon is introduced to a concrete mix in the form of a solid, low-cost, mix-friendly powder, rather than a gas. To clarify the potential strategic benefits of this process, carbonate and bicarbonate-substituted cement formulations were developed to induce carbonation. Raman spectroscopy and correlation function analysis were used to track the spatial distribution and transformation of mineral phases across the first several days of hydration. The results of anal-ysis conducted on samples ranging from the nano to macro scale demonstrate controlled and scalable CO2 storage via carbonate polymorphs, without compromising structural integrity. In tandem with ongoing efforts to minimize the carbon footprint of bicarbonate production, we show that chemically induced pre-cure carbonation has the ability to offset at least 40% of the emissions from the calcination of cement.