Use of Low-CO2 Portland Limestone Cement for Pavement Construction in Canada

M.D.A. Thomas ； K. Cail ； B. Blair ； A. Delagrave ； P. Masson ； K. Kazanis

《International Journal of Pavement Research and Technology》 3卷5期 (2010/09) Pp. 228-233

https://doi.org/10.6135/ijprt.org.tw/2010.3(5).228

並列摘要

In response to growing pressures to reduce the clinker content in cement and hence the CO2 emissions associated with its production, the Canadian Standards Association (CSA A3001-08) introduced a new classification of cement in 2008, this being Portland limestone cement (PLC) containing up to 15% limestone. PLC is now permitted in the production of all classes of concrete in Canada except for sulfate-exposure classes (CSA A23.1-09). Considerable laboratory testing has been conducted in Canada in recent years to demonstrate that PLC with up to 15% limestone can be manufactured to produce equivalent performance to a Portland cement in terms of concrete strength and other properties, including durability. The equivalent performance is achieved by optimizing the PLC with regards to composition and particle-size distribution, and this is achieved by intergrinding rather than blending of the Portland cement and limestone. This paper presents data from a number of recent full-scale field trials where PLC has been used in paving projects in Quebec, Alberta, and Nova Scotia. In each field trial, the performance of PLC concrete has been compared with that of equivalent concrete produced using Portland cement (PC), and concretes have been produced with varying levels (up to 50%) of supplementary cementing materials (SCM). Testing of concrete produced during the field trials has included compressive strength, freeze-thaw and deicer-salt-scaling resistance, chloride permeability, and chloride diffusion. The results indicate that concrete performance is strongly influenced by the level of SCM used, but is independent of whether PLC or PC is used. The use of such PLC has the potential to bring about a 10% reduction in the greenhouse gas emissions associated with the production of Portland cement clinker. The acceptable performance of concrete containing combinations of PLC and SCM will permit further reductions in the CO2 footprint of the concrete; in one mix, the clinker content was just 41% of the total mass of cementing material.

並列關鍵字

Cement reduced clinker ； Concrete paving ； Fly ash ； Portland limestone