Comparative Analysis of the Global Warming Potential (GWP) of Structural Stone, Concrete and Steel Construction Materials

Abstract

The manufacturing and construction industries have always been large contributors to global CO2 emissions, largely as a consequence of material choices. Two of the most commonly used building materials are concrete and steel, but both of these industries have been identified as large sources of atmospheric CO2. Therefore, reducing the use of these materials and finding alternatives to them that meet the engineering requirements of a design, while also minimizing emissions, is becoming increasingly important. Stone in its natural form is a zero-carbon emission material and has strong physical properties that make it a viable substitute for concrete and steel, across a range of applications. Yet research into the potential use of stone by the construction industry remains rare. The aim of this research is to investigate whether the use of stone as a building product is a feasible alternative in terms of carbon emissions. This study compares data from 11 Environmental Product Declarations (EPDs) that provide Life Cycle Analysis (LCA) assessments of their considered product (i.e., types of dimensional stone, concrete, or steel). However, this research also highlights some shortcomings in the EPDs that point to a need for greater legitimate engagement with this tool, and for more consistency between the data being presented in EPDs. Global Warming Potential (GWP) data are compared between products to determine the difference in carbon emissions. The results indicate that GWP values for dimensional structural stone (135 kg.CO2/m3) are 45–75% lower than the concrete products considered in this investigation (246–514 kg.CO2/m3), and over 99% lower than certain steel products (22,294–29,202 kg.CO2/m3). This research indicates that stone is demonstrably better in terms of its GWP, and that a more extensive use of structural stone represents a key opportunity for the construction industry to reduce its CO2 emissions.