摘要: |
This study evaluates Grade 120 Granulated Ground Blast Furnace Slag GGBFS and its effect on the properties of hydraulic cement concretes used in structural and
pavement construction. Several mix designs, structural and pavement, were used for this evaluation with varying amounts of GGBFS used as a substitution for
cement These substitutions were a percentage by weight substitution. This study looked at the effects of slag on workability, constructability, durability and the
compressive strength of the concrete. How GGBFS affected the concrete's set times was also critical in establishing the maximum substitution amount for LADOTD
concrete structures and pavements.
In addition, an informal telephone survey was taken with other state DOT ’ S concerning their use and experience using GGBFS in concrete. This further assisted
LADOTD in the development of their own specifications for GGBFS concretes.
Test results indicate that concretes with GGBFS substitutions displayed delays in set times and exhibited delays in compressive strengths at an early age, as
compared to conventional concrete mixes. However, at later ages the compressive and flexural strengths markedly surpassed those of conventional concrete mixes as
the cement content increased. Permeability was greatly reduced in those concretes that incorporated GGBFS as opposed to the conventional mixes
At this time, the use of GGBFS has already been implemented into the specifications of Louisiana concrete mixes. Conclusions from this study are to be
incorporated into the specifications of Louisiana concrete mixes. Restrictions are for an allowable substitution of Grade 120 GGBFS up to 50%, and an ambient
pouring temperature of 50 °F and rising.
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