This paper reports the results of an investigation into effects of agitation for up to 5 h on the properties of ready-mixed concrete. It is shown that generally the workability of concrete decreases with time of agitation and the compressive strength increases. For a time, the loss in workability is small and it would be necessary in practice to increase only the water content in order to maintain the required workability and strength. For rich mixes and for long periods of agitation, some reduction in strength would occur in so maintaining the required workability. The drying shrinkage of concrete of low cement content is shown to be increased by pro¬longed agitation.
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