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Temperature variation in high slump drilled shaft concrete and its effect on slump loss
Drilled shaft refers to a deep foundation system where a single large diameter pier is used to replace a whole group of piles. High slump self-compacting concrete is used in drilled shafts due to its high fluidity and less proneness to segregation. The Florida Department of Transportation (FDOT) specifications require that such concrete should have a slump between 7 and 9 in. when placed and should maintain a slump of 4 in. or more throughout the concrete placement time. Furthermore, the mix for the slump loss test should be prepared at a temperature consistent with the highest ambient or initial concrete temperature (whichever is greater) expected during actual concrete placement. It is possible that the temperature of concrete inside the drilled shaft is lower than the ambient or initial concrete temperature due to the presence of ground water. If that is the case, slump loss would be less than the loss determined at the highest ambient or the initial concrete temperature, making the FDOT requirement unrealistic. However, it should be experimentally verified. This experimental study was conducted with the objective to establish profiles of concrete temperature in time from placement to hardening along depth as well as across width of the drilled shaft. Based on the gathered data, it was found that no significant temperature differential existed along the depth and across the width of the drilled shaft during the initial setting of concrete. The temperature of concrete inside the drilled shaft was same as initial concrete temperature before placement at all locations. This finding leads to the conclusion that concrete temperature inside drilled shaft is not affected by ambient temperature and/or the underground temperature conditions.
Temperature variation in high slump drilled shaft concrete and its effect on slump loss
Drilled shaft refers to a deep foundation system where a single large diameter pier is used to replace a whole group of piles. High slump self-compacting concrete is used in drilled shafts due to its high fluidity and less proneness to segregation. The Florida Department of Transportation (FDOT) specifications require that such concrete should have a slump between 7 and 9 in. when placed and should maintain a slump of 4 in. or more throughout the concrete placement time. Furthermore, the mix for the slump loss test should be prepared at a temperature consistent with the highest ambient or initial concrete temperature (whichever is greater) expected during actual concrete placement. It is possible that the temperature of concrete inside the drilled shaft is lower than the ambient or initial concrete temperature due to the presence of ground water. If that is the case, slump loss would be less than the loss determined at the highest ambient or the initial concrete temperature, making the FDOT requirement unrealistic. However, it should be experimentally verified. This experimental study was conducted with the objective to establish profiles of concrete temperature in time from placement to hardening along depth as well as across width of the drilled shaft. Based on the gathered data, it was found that no significant temperature differential existed along the depth and across the width of the drilled shaft during the initial setting of concrete. The temperature of concrete inside the drilled shaft was same as initial concrete temperature before placement at all locations. This finding leads to the conclusion that concrete temperature inside drilled shaft is not affected by ambient temperature and/or the underground temperature conditions.
Temperature variation in high slump drilled shaft concrete and its effect on slump loss
Ahmad, Irtishad (Autor:in) / Azhar, Salman (Autor:in)
Cement and Concrete Research ; 34 ; 207-217
2004
11 Seiten, 3 Quellen
Aufsatz (Zeitschrift)
Englisch
Temperature variation in high slump drilled shaft concrete and its effect on slump loss
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