Case Study: CCP’s Potential to Lower Greenhouse Gas Emissions for Australia

摘要

Under the Kyoto Accounting rules, Australia’s National Greenhouse Gas Inventory Report emissions for 2002 was 550.1 Mt carbon dioxide equivalent (CO2-e) being a net increase of 1.3 percent on the 1990 level. This increase is largely attributed to the stationary energy, transport and industrial process sectors, offset with significant reductions from reduced land clearing. For the construction sector additional mitigation strategies could be employed to further reduce Australia’s net CO2-e emissions. For example through increased use of mineral resources like coal combustion products such as; fly ash, iron blast furnace slag and amorphous silica, or commonly referred to as supplementary cementitious materials (SCM’s), used with Portland cement in the manufacture of concrete. For Australia, the manufacture and delivery of one tonne of cement results in the emission of approximately 0.82 tonne of CO2-e or 6.5 Mt of CO2-e emitted for total cement sales in 2002. Using data collected from companies processing fly ash and iron blast furnace slag, life cycle analyses were conducted to demonstrate the reduced embodied energy and resultant CO2-e signature for one cubic meter of concrete containing various combinations of fly ash and iron blast furnace slag. From the resultant data and analysis a simple CO2-e estimator has been developed to assist architects, designers and consulting engineers to specify eco-friendly structures. The case study is based on the construction of a domestic dwelling (four bedroom home) using approximately 130 cubic meters (m3) of 25 Mpa concrete containing binder ratios of 70 percent Portland cement and 30 percent fly ash. The total savings in CO2-e emissions was 9.23 tonnes, or equivalent to emissions from a four-cylinder car for 3.08 years. The paper will briefly discuss Australia’s current National Greenhouse Gas Inventory Report in the context of how increased use of SCM’s in the construction sector can further lower greenhouse gas emissions, whilst still delivering improved durability performance.