What is the purpose of adding fibers to plaster mixtures?

Adding fibers to plaster mixtures primarily serves to improve their cracking resistance and pump-ability. By incorporating fibers, the overall structural integrity of the plaster is enhanced, which is particularly crucial in applications like pool plastering where the surface is exposed to water and varying temperatures.

When the plaster mixture contains fibers, it creates a more cohesive material that can help to minimize the formation of cracks through tension and movement, potentially extending the lifespan of the plaster finish. This enhancement is vital because it reduces the chances of issues that might arise from environmental stresses, such as temperature fluctuations and moisture variations.

Additionally, the inclusion of fibers can aid in the pump-ability of the plaster, making it easier to transport and apply, especially in large commercial projects where efficiency in application is key. This factor can also streamline the work process and ensure a more uniform application across surfaces.

Other options presented, such as improving water retention or enhancing color, do not significantly relate to the primary reasons for fiber addition in plaster mixtures. Reducing drying time is also not a direct benefit of fiber inclusion in plaster formulations. Instead, the focus is on the structural benefits that fibers bring to the composition of the plaster.