Within the first 6-12 hours after pouring, concrete is prone to cracking if its moisture evaporates rapidly. This is mainly due to the shrinkage of concrete that is still in a plastic state due to water loss. When the shrinkage is limited, the tensile stress generated in the concrete exceeds its ultimate tensile strength limit (the plastic state concrete has an extremely low repair value), and the concrete inevitably cracks, commonly referred to as "plastic shrinkage cracks". If the mix proportion of the concrete used is appropriate, the construction method is formal, and the temperature and humidity during the curing period are guaranteed, plastic shrinkage cracks can be reduced or prevented. But under unfavorable construction conditions, especially in harsh weather environments, adding a small amount of polypropylene fine fibers to concrete is an effective technical measure to reduce or prevent plastic shrinkage cracks!!
