Abstract Manager

This paper provides a case study on the implementation and performance of concrete roundabouts in the County of Essex in southern Ontario. The introduction outlines why municipalities are opting for roundabouts, discussing their key features, as well as the benefits and potential risks associated with their use. The paper also references the TAC Canadian Roundabout Design Guide, highlighting its significant content.

The background section covers the fundamental components of concrete pavements, the jointing methods used in concrete roundabouts, and the design considerations for determining roundabout thickness. Design specifics will be given for two roundabouts: one built in 2014 at County Road 22 and County Road 2 in the Municipality of Lakeshore, and the other, more recently constructed in 2024, at County Road 42 and County Road 43 in the Town of Tecumseh.

The construction process of the 2024 roundabout at County Road 42 and County Road 43 will be explored, detailing the subgrade, subbase, and base preparation. The installation of dowel and tie bars, along with the concrete placement process, will be discussed. Jointing and pavement marking procedures will also be covered.

The paper will then examine the performance of the 2014 concrete roundabout, including the longevity of the specially etched pavement markings. It will also compare the performance of asphalt roundabouts in Essex County, pointing out the advantages of switching to concrete roundabouts.

In conclusion, the paper addresses the sustainable benefits of concrete roundabouts, including enhanced light reflectance, lower hydroplaning risks, recyclability of materials, and the incorporation of Portland Limestone cement and industrial by-products in the concrete mix. A comparison of the carbon footprint between the concrete roundabout built in 2014 with general use (GU) cement and the one built in 2024 with general use limestone cement (GUL) will also be presented.