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I will add to what Uzair has said. For mass concrete, recommendations of ACI 207 are used to reduce heat of hydration during curing. This involves replacing cement with a recommended percentage of fly ash and water with crushed ice. The temperature inside foundation is monitored using thermocouples. Generally, contractor has to ensure that no part of concrete mass is allowed to become cooler than the hottest part by more than 20oC (68oF). Thanks.

There are two aspects of this question: a. When the concrete is to be placed in single layer, as in a tunnel construction (what IMO OP has asked for) Recommendations regarding maximum horizontal length of concrete pour for this case, are given in ACI Standard referred in my previous post. When the concrete is reinforced properly, to withstand applied loads as well as thermal cracking, next or adjacent layer of concrete may be cast both sooner (the same day) as well as later (e.g., next morning), depending upon availability of concreting party. Proper construction joint should however be provided at the face of concrete common between the two pours. When the the concrete is to be cast in panels, separated by expansion joints (as in the case of concrete pavements), casting is generally done in alternate panels at one time. b. When the Mass Concrete is to be laid in multiple-layers Guidance regarding Mass Concrete is given in ACI 207.1R-05. AFAIK, no specific time duration has been given by ACI for placement of successive layers in a mass concrete. However, last paragraph of ACI 309R-05 Section 7.2 provides general guidance in this regard, in following words: "When the placement consists of several layers, concrete delivery should be scheduled so that each layer is placed while the preceding one is still plastic to avoid cold joints. If the underlying layer has stiffened just beyond the point where it can be penetrated by the vibrator, bond can still be obtained by thoroughly and systematically vibrating the new concrete into contact with the previously placed concrete; however, an unavoidable layer line will show on the surface when the form is removed." Ways and means are available for execution of large mass concrete works in a single casting operation. Following link gives details of such a mass concreting job, involving casting of 5.5 m (18 ft) thick concrete slabs at 70 m (230 ft) depth belo ground level, carried in one-go using self-compacting concrete. http://www.silicafume.org/pdf/reprints-201407.pdf Regards.