Acrylic AC50 fibers are monofilament and have more surface area than bundled fibers. Because of this, they can easily choke up a concrete mix if they are overdosed or not carefully blended in. Some users find blending the fibers in the mix water first provides optimal dispersion. Others prefer to slowly blend the fibers into the concrete later in the mixing process. Some experimentation is suggested to determine the best solution for a specific mix design.