Thermal Effects of Mass Concrete Pour 3

[MkAustin]

We are performing materials testing on a 4-ft thick concrete slab pour with 1500 cy. The specifications are loose and the contractor is going to do one continuous pour. The maximum specified placement temp is 95 deg and there are no specific requirements for cooling. The pour will start in early evening and go all night. Night time temp is 75 deg F and daytime temp is 100 deg F. No chance to delay project until cooler weather. We didn't design this but are concerned the heat of hydration may cause problems. I am a geotech with no experience with thick concrete pours. Any comments on whether there may be problems with this thick of a pour and ways to address this? Thanks.

 

[dik]

From my General Notes File (this is now in excess of 230K text file):

MASS CONCRETE

CONCRETE POURS HAVING A TOTAL VOLUME IN EXCESS OF 5 CU-M AND A MINIMUM DIMENSION IN EXCESS OF 3 FT SHALL BE CONSIDERED AS MASS CONCRETE

CONCRETE WORK SHALL COMPLY WITH THE RECOMMENDATIONS OF ACI COMMITTEE 207

CEMENT TYPE FOR MASS CONCRETE SHALL BE TYPE LH UNLESS APPROVED BY THE [CONSULTANT | ENGINEER]

MAXIMUM AGGREGATE SIZE SHALL BE 2" UNLESS APPROVED BY THE [CONSULTANT | ENGINEER]

PROVIDE PAIRS OF THERMOCOUPLES IN THE CENTRE OF MASS OF THE CONCRETE POUR

PROVIDE SURFACE THERMOCOUPLE PAIRS AT THE TOP SURFACE OF THE CONCRETE POUR DIRECTLY ABOVE THE THERMOCOUPLE PAIR AT THE CENTRE OF MASS, NEAR THE CENTRE OF TWO ADJACENT VERTICAL FACES AND AT ONE CORNER (5 SURFACE PAIRS TOTAL)

SURFACE THERMOCOUPLE PAIRS SHALL BE PLACED 2" FROM THE OUTSIDE SURFACE AND AT MID DEPTH OF THE CONCRETE POUR

THERMOCOUPLE PAIRS SHALL BE SEPARATED BY A DISTANCE OF APPROX 4'

MAXIMUM TEMPERATURE AT THE CENTRE OF MASS SHALL NOT EXCEED 50%%DC

MAXIMUM TEMPERATURE DIFFERENTIAL BETWEEN THE CENTRE OF MASS AND THE CONCRETE SURFACE SHALL NOT EXCEED 25%%DC

CONTRACTOR SHALL PROVIDE A PROCEDURE OUTLINING PROPOSED METHOD FOR MAINTAINING TEMPERATURE REQUIREMENTS FOR REVIEW BY THE [CONSULTANT | ENGINEER]

Dik