3824.40 - Prepared additives for cements, mortars or concretes:

HTS Code 3824.40 encompasses prepared additives specifically designed for use in cements, mortars, and concretes. These substances are not part of the cementitious mixture itself but are added to modify or enhance the properties of the final hardened product. Examples include plasticizers, accelerators, retarders, waterproofing agents, and air-entraining agents. The purpose of these additives is to improve workability, strength, durability, setting time, or other performance characteristics of construction materials.

This category is distinct from its sibling, 3824.10, which covers prepared binders for foundry molds and cores, a separate industrial application. Unlike 3824.50, which classifies nonrefractory mortars and concretes as finished or semi-finished products, 3824.40 focuses solely on the chemical additives introduced into these materials during their preparation or application.

Subcategories within 3824.40 further refine classification based on the composition of the additive. 3824.40.10 distinguishes additives containing significant proportions of aromatic or modified aromatic substances. 3824.40.20 covers those composed entirely of inorganic substances, while 3824.40.50 serves as a residual category for other prepared additives not meeting the criteria of the preceding subheadings. This granular approach aids in precise customs declarations by accounting for the diverse chemical formulations employed in construction.