Using a polyether-based polycarboxylic acid water reducer in high slump concrete can offer several advantages:

- Improved Workability: The water reducer will help achieve the desired high slump while reducing the water content of the mix. This results in improved workability without sacrificing the concrete's performance.

- Reduced Water-Cement Ratio: By reducing the water content, you can lower the water-cement ratio, which is critical for achieving strong and durable concrete.

- Enhanced Strength and Durability: Maintaining a proper water-cement ratio can lead to higher compressive strength and long-term durability of the concrete.

- Control Over Setting Time: Some polycarboxylic acid water reducers can also provide control over the setting time of the concrete, allowing for adjustments to suit specific construction needs.