In order to provide the strongest and most durable concrete, the aggregate contained in the mixture must be the best possible in terms of gradation, shape, strength, and cleanliness. During the design of a concrete mixture, the aggregate selected for use must adequately meet those requirements. To determine this, various tests are performed. These include tests for

Table 15-4.-Recommended Slumps for Various Types of Construction

gradation; specific gravity, absorption, and surface moisture; impurities, such as organic material, clay, or other water-absorbing particles; and soundness, which is the property of an aggregate to resist disintegration due to freezing and thawing. Although these tests are not included in this TRAMAN, you may refer to NAVFAC MO-330, Materials Testing, should you desire to learn more about them.