Which of the following does not help prevent the occurrence of honeycombs in concrete?

The choice involving the use of Type IV cement is correct in the context of preventing honeycombs in concrete because the type of cement influences the hydration process and the rate at which heat is generated during curing, but it does not directly address the physical issues that lead to honeycombing. Honeycombing occurs primarily due to inadequate consolidation and improper placement of concrete, which results in voids and gaps in the hardened material.

Selecting the proper coarse aggregate size is crucial as it ensures better packing of aggregates, allowing the concrete mix to fill voids more completely during consolidation. Water-reducing admixtures improve workability and flow, which is essential for minimizing air pockets and voids during placement. Compacting freshly placed concrete is a direct mechanical method to remove trapped air and consolidate the mix, thereby filling all voids effectively and significantly reducing the risk of honeycombs.

In summary, while Type IV cement has its advantages in specific applications, it does not play a significant role in the prevention of honeycombs compared to the more practical measures of proper aggregate selection, the use of admixtures for better workability, and effective compaction of the concrete.