What type of aggregates have little variation in size?

The correct answer is gap graded aggregates, which are characterized by having a limited range of particle sizes. In gap graded aggregates, certain sizes of particles are omitted, leading to less variation in the overall size distribution compared to other types of aggregates. This specific grading can enhance certain properties of mixtures, such as reducing the void spaces and improving the mechanical performance of the composite material.

Well graded aggregates have a good distribution of various particle sizes, which helps fill the spaces between larger particles with smaller ones, promoting better compaction and strength. Poorly graded aggregates, on the other hand, exhibit a narrow range of sizes and can lead to larger voids within the mixture. Coarse aggregates refer to larger particles in aggregate mixtures but do not specifically denote the uniformity or size variation of the particles present.

Thus, gap graded aggregates stand out for their characteristic of having less size variation, which can be advantageous in specific construction applications where uniformity in particle size is desired.