The next Peer-to-Peer webinar will take place on Monday June 23rd, 2025 at 2pm Eastern Time and will be one hour long (2*20 minutes presentations + 15-minute interaction). The registration for this webinar is free.
REGISTER FOR FREE HERE.
Theme of the Peer-to-Peer Webinar: Biopolymer-Stabilized Earth: A Material Perspective
Speaker 1: Erfan Mardan, Columbia University, USA
Title 1: Facilitating earthen construction via additive manufacturing and bio-stabilizers
The urgent need for low-carbon construction has revived interest in earth-based materials, which are abundant, recyclable, and environmentally benign. While 3D-printed earth structures offer a compelling alternative to cement-based systems—achieving up to 88% lower carbon emissions—their practical application is limited by poor workability, slow drying, and inconsistent mechanical performance. This research investigates the role of biopolymers in tuning the microstructure and fresh-state rheology of clay-rich mixtures to enhance their 3D printability. By systematically studying the interactions between clay minerals and various biopolymers across different water and polymer contents, the study identifies mechanisms—such as biopolymer bridging and suspension stabilization—that govern yield stress, modulus, viscosity, extrusion, and printing behavior. These findings offer a scientific foundation for the predictive design of biopolymer-stabilized earthen materials, advancing their potential for scalable, sustainable additive manufacturing in construction.
Speaker 2: Rebecca Mikofsky, University of Colorado Boulder, USA
Title 2: Clay-Polymer Interactions Towards High-Performance Biopolymer-stabilized Earthen Materials
Earth has been used globally as a construction material for at least 10,000 years. As an abundant, locally available, natural resource with excellent thermal properties, earthen building materials offer a promising sustainable alternative to the high environmental impacts of conventional concrete materials. However, traditional earthen materials often suffer from low-strength and poor durability. While biopolymer additives have been shown to improve these properties, little work has been done to explore the complex physicochemical interactions of biopolymer-stabilizers with earth and how these interactions connect to the physical properties.
This work investigates the physicochemical interactions between five polysaccharides (guar gum, locust bean gum, methylcellulose, sodium alginate, xanthan gum) and two common clays (bentonite and kaolinite) across five pH values (3,5, 7, 9, and 11), and links these interactions to physical properties. At the micro-scale, interactions were evaluated through mineral binding characterization method using Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and zeta potential. At the macro-scale, fresh-state rheology and hardened-state mechanical strength were measured.
This presentation outlines our key findings on how clay-biopolymer interactions impact macro-scale properties, as well as providing a future outlook towards development of sustainable, high-performance earthen building materials.
This webinar is brought to you by the RILEM Youth Council (RYC) and hosted by Olga Beatrice Carcassi (North America and Carribean RYC representative).
