Contrasting the environmental impact of conventional walls and magnesium oxychloride walls

Abstract

As sustainability is becoming a priority in the construction industry, concerns associated with the environmental impacts of the production and use of Portland cement (PC) are being raised. As a substitute binder of PC, this study investigates the performance and environmental assessment of Magnesium Oxychloride Cement (MOC) wall panels. Since the main binder component of MOC is magnesia (MgO), the carbon footprint and environmental impacts of MgO produced in Alberta (Canada) are first calculated and compared with Portland Cement (PC). While the main energy sources of MgO and MOC production in the world are coal and oil-based fuels, this research is the first to evaluate the environmental assessment of using Natural gas in the production process. After that, the LCA of MOC wall panels at the product stage is compared with two PC concrete-based products (tilt-up and insulated concrete form-ICF) and two wooden-based walls scenarios to obtain a comprehensive assessment and comparison of environmental problems. The results show that the production of MgO in Alberta has a higher environmental impact than PC production. However, the CO2 emission of MgO produced by natural gas is 18% less than MgO produced by coal. The CO2 emission of the MOC panel is 37.3 (kg CO2 eq/m2), which is at least 22% less than the CO2 emission of PC concrete-based scenarios (105 kg CO2 eq/m2 for tilt-up and 48 kg CO2 eq/m2 for ICF). The CO2 emission of wooden-based scenarios ranges between 19.12 and 28.7 (kg CO2 eq/m2) which is lower than MOC panels. However, there are physical and technical limitations for wooden-based wall products that encourage their replacement with MOC panels. The sensitivity analysis shows that adding 1 kg MgO to the MOC boards leads to 1.4 kg increase in CO2 emissions. Additionally, 1kWh energy saving in the production process provides 1 kg less CO2 emissions.