Thesis Defence: A Building Information Modeling-Integrated Life Cycle Assessment Framework for Low-Carbon Foundation Design: Comparing Supplementary Cementitious Materials and Soil Stabilization

Pirthvi Raj, supervised by Dr. Sumi Siddiqua, will defend their thesis titled “A Building Information Modeling-Integrated Life Cycle Assessment Framework for Low-Carbon Foundation Design: Comparing Supplementary Cementitious Materials and Soil Stabilization” in partial fulfillment of the requirements for the degree of Master of Applied Science in Civil Engineering.

An abstract for Pirthvi Raj’s thesis is included below.

Defences are open to all members of the campus community as well as the general public. Please email sumi.siddiqua@ubc.ca to receive the Zoom link for this defence.

Abstract

Foundations are among the most concrete- and steel-intensive parts of a building, making them a key lever for enhancing building sustainability. Life cycle assessment (LCA) is a well-established method for quantifying environmental impact throughout the life cycle of materials or services, yet its application to building foundations remains limited. This study presents a largely automated, reproducible BIM-integrated LCA workflow to quantify the cradle-to-gate embodied carbon of three shallow foundation systems, each drawn from a separate building under Western Canadian conditions, and to evaluate two decarbonization measures within each: partial replacement of Portland cement with supplementary cementitious materials (SCMs), calcined biomass fly ash (CFA), ground granulated blast-furnace slag (GBFS), and biochar, and chemical stabilization of the founding soil. The boundary is drawn at the point of material delivery to the site, targeting design-stage choices rather than construction-stage execution. Foundation quantities were extracted automatically from Revit models and used to construct and calculate the life-cycle inventory programmatically in openLCA. Results show that each building’s own geometry, not foundation type as a category, governs the scale of its embodied carbon; SCM substitution reduced the footprint by up to 26% (GBFS), 23% (CFA), and 6% (biochar), though the GBFS–CFA ranking reverses when the same binders are deployed for soil stabilization instead of concrete substitution. A Monte Carlo uncertainty analysis confirmed the SCM reductions and the ineffectiveness of soil stabilization at the isolated scale are robust, while the CFA–GBFS ranking and biochar’s modest reduction are not statistically distinguishable. Crediting biochar’s stored biogenic carbon, excluded under the production-only boundary applied throughout, brings its production intensity to net-negative and its performance to competitive with the other two SCMs. A multi-category assessment confirmed these savings do not shift burden to other impacts. The findings offer practical, early-design guidance for lower-carbon foundations in British Columbia.