It took great planning and an incredible feat of engineering for Boral to deliver 2500m3 of concrete in one of the biggest elevated continuous pours in NSW history. Five boom pumps were required to deliver 2500m3 over the 18 hour continuous pour.  Baulderstone is the managing contractor on Port Botany’s Grade Separation works.

The project involves a large elevated bridge / roundabout that will streamline traffic access to Port Botany’s T3 and Brotherson Docks. Spanning more than 75m, the new roundabout required a continuous pour of concrete to ensure the optimal post tensioning sequence of the support girders. This would also minimise the number of construction joints for high durability.

Geoff McDonnell, the Sydney Metro Concrete operations manager, carefully planned delivery of the pour for several weeks. When it took place on a weekend in March this year it involved more than 60 concrete trucks and 18 testers working over two shifts to deliver the concrete via five boom pumps over an 18 hour period.

Delivery was planned from both the Boral Botany and St Peter’s plants, with backup from Artarmon.

As the post tensioned bridge comprised a 400mm deck and 2200mm deep girder, Boral utilised its technical knowledge to design a low heat, high durability, high workability (160mm slump, small aggregate) mix to achieve Sydney Ports Corporation’s wet and hardened concrete requirements.

The project required significant logistics to ensure around 400 loads of concrete performed satisfactorily, requiring individual slump tests and approximately 400 test cylinders.

Boral Concrete collaborated with Boral Quarries, Cement and Logistics to ensure the success of the project with supply of 4000t coarse/fine aggregates, and 1200t cement.

Baulderstone was pleased with Boral’s service, with the Site Supervisor remarking that there was not one concrete placer complaint received for concrete workability on the day or night.

When the project is finished later this year, there will be three access ramps and four bridge spans linked to the roundabout providing access to tenants north of Port Botany.

Previously, Baulderstone and Boral had successfully delivered 95,000m3 to the adjacent new Hutchison Ports Terminal sea wall.

By Julie Adamo - Regional sales manager NSW/ACT, Boral Construction Materials.

Article reproduced with kind permission of the Concrete Institute of Australia.

Taken from the April 2013 NZRMCA Newsletter