Investigating the Upper Limit of the Slump Test to Specify the Consistency of Fresh Concrete

A slump test measures the flowability of fresh concrete, which affects how it can be placed and compacted without separating or bleeding.

Slump tests are used to assess conventional concrete that requires vibration during pouring, rather than highly flowable self-consolidating concrete. However, current Australian standards don’t clearly define when the slump test becomes unreliable for self-consolidating mixes, making it difficult for builders and engineers to know exactly which concrete mix is suitable for their project.

In this research collaboration, Main Roads WA partners with Curtin University to conduct extensive experimental studies on different concrete mixes to figure out where the slump test stops being accurate. They will determine a clear upper limit for slump values, after which the more advanced spread test should be used for very flowable concrete. They will also study how workability affects the strength and durability of hardened concrete.

The project will run these tests for traditional concrete mixes and sustainable concrete mixes made from recycled aggregates and supplementary cementitious materials. The outcomes of the project will help builders and engineers confidently specify the right kind of concrete for each structure—avoiding confusion and ensuring the correct mix is delivered to construction sites.

PROJECT PARTNERS

• Main Roads WA
• Curtin University