Final answer:
An additive is an ingredient added to a concrete mix to change its physical or chemical characteristics.
Step-by-step explanation:
Additives play a pivotal role in modifying the physical and chemical attributes of concrete mixes, contributing to enhanced properties such as strength, durability, workability, and setting time. These substances, aptly named additives, are meticulously incorporated into concrete formulations. Examples of widely employed additives encompass plasticizers, which enhance workability; accelerators, fostering quicker curing; extending setting time; air entrainers, improving freeze-thaw resistance; and water reducers, optimizing the mix's fluidity without compromising strength. The judicious use of additives underscores the versatility of concrete as a construction material, allowing tailored adjustments to meet specific project requirements and environmental conditions.