Workability consistency is the most important quality control parameter as far as concrete construction is concerned. Workability retention plays a critical role in maintaining the required consistency. Concrete loses workability due to two main mechanisms: (a) plastic stiffness caused by water loss in the mix because of evaporation and early cement hydration – a gradual workability loss that can be partially reinstated, and (b) structural build up, or thixotropy – temporary workability loss that can be reversed. The degree of workability loss depends on many factors. Particle size distribution and their packing, cement chemistry, ambient conditions, time, to list only some. Maintaining required workability of self-compacting concrete (SCC) is far more important than of conventional vibrated concrete (CVC), as the quality of finished concrete structures made of SCC nearly entirely depends on the plastic properties of SCC. If neglected, it can cause surface defects, and durability and structural failures of concrete structures.
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