Aggregates also provide strength, durability, stability and resistance to various environmental factors.

However, not all aggregates are suitable for every purpose. Some aggregates may have defects or impurities that can affect their performance and quality.

Therefore, it is important to test aggregates before using them in construction projects. Testing aggregates can help to determine their physical and chemical properties, such as size, shape, density, moisture content, abrasion resistance, soundness, alkali-silica reactivity and more.

Testing aggregates can also help to select the best type and proportion of aggregates for a specific application.

For example, coarse aggregates are better for making concrete that needs high compressive strength, while fine aggregates are better for making mortar that needs good workability.

Testing aggregates can also help to optimize the use of natural resources and reduce the environmental impact of construction activities.

tests on coarse and fine aggregates

Impact of Aggregates in Concrete w.r.t Tests

PropertyCoarse AggregateFine Aggregate
Size 4.75 mm to 80 mm
Small aggregates – high strength, low permeability
Large aggregates – less cement requirement, improves workability
0.06 mm to 4.75 mmFineness Modulus2.9 – 3.2 (Coarse sand)2.6 – 2.9 (Medium sand)2.2 – 2.6 (Fine sand)

Well graded aggregate – dense and uniform concrete
mixPoorly graded aggregate – segregation, bleeding or honeycombing in the concrete mix
Affectsworkability, strength and durability of concrete
ShapeAngular, rounded, flaky or elongated
Impact Angular aggregate – large surface area, high strength and bond with cement, more water and cement requirement (considered best for concrete mix)Flaky and Elongated aggregate – Poor shape, reduction in strength and durability of concrete.
Angular, rounded
Impact Round shaped fine aggregate – better workability, less water demand but reduce strength and interlocking of the mixture.
Angular shaped fine aggregate- high water demand, poor workability.
Affects Packing density, surface area and interlocking of aggregates
TextureRough textured, Smooth textured
Rough aggregates – High strength and resistance to cracking, high water requirement
Rough textured, Smooth textured
Smooth textured fine aggregate- less surface area, less bond with cement, less water requirement
Friction and bond between aggregates and cement paste
Specific Gravity2.4 to 2.9
High specific gravity – high density, low porosity, high strength and durability
2.6 to 2.8
High specific gravity – heavy and stronger fine aggregate
AffectsWeight, density and quality of aggregates
Water Absorption0.5% to 5%.
High absorption aggregates – high moisture content, low water- cement ratio, low strength and high shrinkage
0.5% to 2%.
High absorption aggregate – more porous and rougher finer aggregateLow absorption aggregate – less porous and smoother fine aggregate
AffectsMoisture content and water-cement ratio of concrete
Moisture contentImpact
High moisture content aggregates – Low weight and high volume results in lower strength and higher air content
High moisture content aggregates- segregation, bleeding and reduced bond strength
Affectsweight and volume of aggregates and consequently the mix proportions and yield of concrete
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In certain countries the impact and affects of aggregates are done using some standard codes. For example the American Civil Association, has some codes for different properties of aggregates.

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