Short & long term properties of self-consolidating concrete incorporating fly ash and local aggregate
Self-consolidating concrete (SCC) is a high performance concrete that flows under its own weight so that filling forms containing congested reinforcement is possible without mechanical vibration within placements. There has been growing interest to use SCC for precast and prestressed concrete elements. Therefore, it is important to examine the mechanical and durability properties of SCC to gain insights for the design and implementation of SCC in structures. This thesis presents the mechanical and durability experiments used for characterization and acceptance of SCC. Because there are many normally vibrated concretes (NVC) used today for structural applications, comparisons between the mechanical and durability properties of SCC and an NVC typically used in New Mexico bridges are performed to evaluate the performance of SCC. Two sources of local aggregate in New Mexico were used to produce SCC and NVC mixes. Mechanical properties include compressive and flexural strength, and static and dynamic modulus of elasticity. Durability properties include chloride ion resistance, freeze-thaw durability, and potential for alkali-silica reaction (ASR). Experimental investigations show that SCC can have similar strength characteristics compared to NVC. Lowering the water to total cementitious materials ratio causes SCC to gain significant strength properties without compromising the requirements for plastic properties. Furthermore, results show that chloride ion resistivity in SCC is adequate, and in many cases exceeded that of NVC. It is recommended that air void systems of SCC are examined in the future due to discrepancies in freeze thaw durability results of SCC. Finally, it was found that SCC does not have higher potential to ASR compared with NVC in the presence of reactive aggregate even when high dosages of chemical admixtures are provided.
Self-consolidating concrete, Fly ash, Concrete--Mechanical properties, Concrete--Service life.
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