Modeling the environmental consequences of implementing sectoral environmental strategies: Focus on the CSI clinker-cement lever and the role of alternative mineral additions in Canada

 

Jean-Martin Lessard (PhD student, civil and building engineering, USherbrooke)

Supervisor: Ben Amor

Co-supervisor: Arezki Tagnit-Hamou

Co-supervisor: Guillaume Habert, ETH Zürich

Context

To evaluate the effectiveness of an environmental strategy in the construction sector, such as the use of recycled materials, current studies fail to include short- and long-term market adjustments and intersectoral and interregional constraints. However, the effectiveness of the latter will depend on the new balance of trade flows after its introduction, where new demands for materials, or new prices will force an adjustment of supply in a set of markets. These adjustments may include changes in imports and exports, the development of new materials / products, or the development of new open-loop recycling channels for industrial by-products or post-consumer waste (eg glass powder from mixed color glass products waste). This information is crucial in implementing strategies to avoid, among other things, unforeseen impacts and shifting problems to other sectors.

Goal

The main goal of this project is to develop a model for assessing the direct and indirect consequences of implementing an environmental strategy in the construction sector. As a case study, this project focuses on the Canadian consequences of implementing the Cement Sustainability Initiative (CSI) clinker-cement strategy. It aims to replace by 2050 by 40% the mass of clinker contained in Portland cements by mineral additives (MA). However, the Canadian supply of conventional MAs such as silica fume, blast furnace slag, and fly ash is becoming increasingly limited. As a result, this project will also focus on the role of alternative MAs, such as glass powder, limestone filler and metakaolin, in achieving this goal by 2050.

Methods

This project focuses on the development of a cost-effective material-to-product (M-P) chain coupled with Life Cycle Assessment (LCA) tools. An economic M-P chain is a multi-material, multi-product, and multi-market chain whose core is a model of economic equilibrium coupled with material balance equations. This type of model seeks to minimize supply costs to meet the demand for a set of products and markets at a given time, by optimizing material flows. Where appropriate, industries and geographic markets have been selected to reflect the Canadian reality of the cement industry. A set of four industries (Portland cement, glass container, coal-fired electricity, and steel) interconnected in four markets (eastern Canada, western Canada, northern United States and the rest of the world) is modeled. Demand for products, availability of materials, technological capacity and economic contexts (taxes and subsidies) are projected until 2050 using macroeconomic indicators, national statistics and sectoral data. Second, trade flows are optimized to minimize the production and disposal costs of each industry. Finally, the results obtained are coupled with the Ecoinvent v3.5 database and the Impact World+ characterization method in order to characterize changes in environmental impacts (eg climate change, destruction of the ozone layer, human toxicity, aquatic / terrestrial acidification, depletion of abiotic resources and eutrophication, etc.).

 

Applications

This project will make it possible to assess a priori the short and long-term consequences of the implementation of environmental strategies in the construction sector, such as the CSI clinker-cement strategy. This novel approach will include adjustments for intersectoral and interregional trade flows, while considering regional production constraints and the economic context. Finally, this project will provide better support for decision making in the implementation of environmental strategies in the construction sector, preventing unintended consequences and the transfer of problems in other sectors.

Partner

Chaire SAQ sur la valorisation du verre dans les matériaux