Concrete slump variation at site, how to deal with it?

Adjusting the slump of concrete is a part of the concreting process, which the contractors should manage properly and cautiously. The concrete slump variation from one transit mixer to another is generally due to aggregate moisture content, concrete temperature, mixing process; and time of delivery, waiting, and unloading. Sometimes, the concrete slump variations at the site raise disputes between the parties involved in the construction process. Therefore, it is crucial to clarify the reason behind the need for concrete slump adjustment and the way it should be done in the field. If the concrete slump falls outside the specified range, the slump needs to be adjusted. If the slump is low, introducing water or superplasticizer to the concrete in the mixer can solve the problem. However, if the slump value is high, adding cement to fresh concrete in the transit mixer, extra revolutions of concrete in the mixer, or introducing silica fume can tackle the problem. The slump adjustment is both expensive and time-consuming, and it may not always be effective.