Technical-Resources-for-Concrete-Contractors
Technical-Resources-for-Concrete-Contractors
Technical-Resources-for-Concrete-Contractors
Technical-Resources-for-Concrete-Contractors
Technical-Resources-for-Concrete-Contractors
Technical-Resources-for-Concrete-Contractors

Setting Time Expectations for Hard -Trowel Finishing

ASCC Position Statement #15

Project specifications rarely set limits on concrete setting time. Concrete producers sometimes address setting-time requirements. Concrete contractors must always consider setting times because of the large impact that setting time has on the overall construction schedule, manpower and equipment allocation, and time required for each concrete placement. To determine an appropriate in-place concrete cost for bidding purposes, contractors must estimate the waiting time needed before finishers can start floating. This waiting time is related to setting time.

In a survey, ASCC members were asked how long they expected finishers to wait before they began floating concrete at 50, 70, and 90 °F (10, 20, 30 °C) (“The Cost of Waiting,” Concrete Construction, June 2000). Concrete is usually ready to be power floated when there’s a 1/4 in. (6 mm) or less footprint indentation and no visible surface bleed water. Waiting times from the survey are as follows:

ASCC Contractor Expected Waiting Times

Temperature  Time to start power floating
(1/4 in. footprint)
 At 50 °F  4-1/4 h
 At 70 °F  2-3/4 h
 At 90 °F  1-3/4 h

 

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