Final answer:
The effective period for increased workability when using super plasticizer in concrete placement is typically 30 to 60 minutes. This period is essential for pouring, placement, and finishing operations, and can be influenced by various factors.
Step-by-step explanation:
The question asks about the effective time period for increased workability when using a super plasticizer in concrete placement. Super plasticizers are chemical admixtures that enhance the flowability of concrete without requiring extra water. The typical effective period for increased workability provided by super plasticizers ranges from 30 to 60 minutes after their addition to the concrete mix. This time frame is critical as it affects the pouring, placement, and finishing operations of concrete constructions.
It's important to note that factors like temperature, concrete mix design, and the specific type of super plasticizer can influence the actual workability time. Monitoring the concrete's slump can help determine the right time to place the concrete before the super plasticizer's effect begins to diminish.