Aggregates are one of the most essential materials used in civil engineering and construction. They form a major part of concrete, mortar, and road works, directly affecting the strength, durability, and quality of a structure. Common aggregates include crushed stone, gravel, sand, and slag, all of which must meet specific quality requirements before use.
This is where aggregate testing becomes important. By conducting standard tests, engineers can ensure that the aggregates used are suitable for construction and will perform well over time. In this blog, we will explain what aggregates are, their types, and the different aggregate tests carried out as per relevant IS codes, in a clear and easy-to-understand manner.
What are Aggregates?
Aggregates are raw building materials generated from both natural sources, such as rivers, pits, and quarries, and artificial sources. There are mainly two types of aggregates based on their size: Coarse and fine aggregates.
- Coarse aggregates are the particles that remain on a 4.75 mm sieve. Crushed chips (broken stones), gravels, pebbles, clinkers, and cinders are used as coarse aggregate in concrete.
- Fine aggregates pass through a 4.75 mm sieve and are retained on a 0.075 mm sieve. River sand and manufactured sand of this size are used as fine aggregate in concrete.
OEC trade data (2025) indicates India accounted for 2.63% of global exports of gravel and crushed stone, ranking it 12th worldwide.
Importance of Aggregate Testing
Along with building firms, builders, engineers, architects, and material suppliers also prioritise aggregate testing, as it is crucial to fulfil material standards set by the Indian government.
The following are reasons why the aggregate test is important:
- Advanced checking of the aggregate materials quality helps to avoid future structural failures that could cause safety risks to occupants
- Testing ensures that the selected aggregates meet the required strength, durability, and safety criteria essential for reliable construction.
- Testing helps to check how well aggregates can resist weather and friction, making buildings last longer.
- Test results confirm whether the aggregates comply with applicable Indian and international standards, ensuring regulatory and technical compliance.
- Conducting aggregate testing helps to choose the right aggregate type, saving future repair costs.
- Test results also help to predict the building performance under different environmental conditions.
Common Aggregate Tests in Civil Engineering
The following are aggregate test lists, conducted before using them for the construction process:
- Sieve Analysis (particle size distribution)
- Aggregate Crushing Value (ACV) Test
- Aggregate Impact Value (AIV) Test
- Los Angeles Abrasion Test
- Specific Gravity and Water Absorption Test
- Flakiness and Elongation Index Test
- Soundness Test (using sodium or magnesium sulfate)
1. Sieve Analysis of Aggregates
The sieve analysis test is used to determine the particle size distribution of the coarse and fine aggregates. This test is governed by IS: 2386 (Part I) – 1963.
Here, a balance for weighing, a set of IS Sieves of sizes: 80mm, 63mm, 50mm, 40mm,31.5mm, 25mm, 20mm, 16mm, 12.5mm, 10mm, 6.3mm,4.75mm, 3.35mm, 2.36mm, 1.18mm, 600µm, 300µm, 150µm and 75µm are used.
The aggregates will be passed through them from the larger sample, collecting particles of different sizes left on various sieves.
The minimum weight for the aggregate sample should not be below the weight as follows:
| Maximum size present in substantial proportions(mm) | Minimum weight of sample dispatched for testing (kg) |
| 63 | 100 |
| 50 | 100 |
| 40 | 50 |
| 25 | 50 |
| 20 | 25 |
| 16 | 25 |
| 12.5 | 12 |
| 10 | 6 |
| 6.3 | 3 |
2. Aggregate Crushing Value (ACV) Test
Aggregate Crushing Value (ACV) is the indication of how strong or tough the stones (aggregates) are when they are pressed or crushed under a gradually increasing compressive load. It presents the strength of the aggregate, which is essential for buildings.
The Aggregate Crushing value test will be conducted using a steel cylinder (diameter of 15 cm) with the plunger and base plate, a metal tamping rod, a balance for weighing, a compression testing machine, and IS sieves of sizes 12.5 mm, 10mm, and 2.36 mm, following IS Code 2386-4 (1963).
According to the Indian Roads Congress (IRC):
- For cement concrete surfaces (like road pavements or top layers where vehicles move), the Aggregate Crushing Value (ACV) should not be more than 30%.
- For other concrete works (like the lower layers, foundations, or non-traffic areas), the ACV can be up to 45%.
3. Aggregate Impact Value (AIV) Test
Impact value of aggregate is the aggregate’s ability to resist sudden load or impact load. It can also be understood that the aggregate’s resistance to failure by impact load is known as the Impact Value of Aggregate.
The aggregate impact test can be conducted using an Impact Testing Machine for Aggregate IS sieves (12.5 mm, 10.0 mm, and 2.36 mm), a cylindrical measure and cup, a Weighing balance, and a Tamping rod.
Maximum Allowable Impact Value of Aggregate for Different Types of Pavements
| Sr. No. | Types of Pavements | Maximum Aggregate Impact Values |
| 1 | Water Bound Macadam (WBM) Sub-Base Course | 50 |
| 2 | Cement Concrete, Base Course | 45 |
| 3 | i) WBM base course with bitumen surfacing ii) Built-up – Spray grout, base course | 40 |
| 4 | Bituminous macadam, base course | 35 |
4. Los Angeles Abrasion Test
The Los Angeles abrasion test is conducted on coarse aggregate to determine the percentage of wear and tear due to rubbing action, indicated by the abrasion value. This test procedure is performed using the Los Angeles Abrasion Machine, 11 steel balls, a Weighing balance, and IS sieves of sizes 20, 12.5, 10, and 1.7mm, following IS 2386(Part 4):1963 and BS 812-113:1990 standard codes.
For surface wearing courses, the abrasion value should not be more than 30%. For other layers (below the top surface or in areas with less traffic), the abrasion value can go up to 45%.
4. Specific Gravity and Water Absorption Test
Specific gravity of aggregate is the ratio of the aggregate’s weight to the weight of an equal volume of water. Aggregates with a lower specific gravity value are generally weaker than those with a high specific gravity. With the water absorption test, you can determine whether an aggregate is porous, helping to prevent water absorption in the built structure.
This test will be conducted using a density basket, a weighing balance, a water tank, a tray, and IS sieves of 10mm and 20mm size, following the standards IS 2386(Part 3):1963 and BS 812-2:1995.
To suit the construction use, the specific gravity of aggregates ranges from about 2.5 to 3.0, and water absorption ranges from about 0.1 % to 2.0 %
5. Shape Test/Flakiness and Elongation Index Test
Any building or infrastructure construction involves the use of aggregates of various sizes and shapes based on design requirements. To achieve better strength and bonding for durability, the use of flaky and elongated aggregates needs to be avoided. Instead, using cubical, rounded or angular aggregates gives better results.
Flaky aggregates will be thinner than their average size or mean dimension. Elongated aggregates will be longer than their average size. To check this, the Flakiness Index test and the Elongation Index test will be conducted.
These tests will be conducted using a thickness gauge, a length gauge, a weighing balance and IS Sieves following IS 2386(Part 1):1963.
The recommended combined result of these shape tests (Flakiness + Elongation Index) should be between 15% and 30%, depending on where the aggregates are used.
6. Soundness Test
For aggregates, a soundness test will be performed to understand their ability to withstand external weathering. When aggregates are exposed to the physical and chemical actions of wind, rainwater, and groundwater, or weathering actions like thawing, freezing, and drying, their overall volume can change. This can impact the overall durability of construction over time.
The soundness test of aggregates will be conducted using sodium sulfate or magnesium sulfate solution, an oven, a weighing balance, IS sieves, and a weight balance, following IS-2386 (Part-5). This test involves repeatedly submerging an aggregate sample in a saturated sodium or magnesium sulfate solution, followed by oven drying. After multiple cycles, the aggregate will be sieved to measure the percentage of weight loss, which shows its durability.
The percentage of weight loss indicates the aggregate’s durability.
- If the loss is high, the aggregate is unsound (poor quality).
- If the loss is low, the aggregate is sound (good quality).
Recommended limits:
- When tested with Sodium Sulphate, weight loss should not exceed 12% after 10 cycles.
- When tested with Magnesium Sulphate, weight loss should not exceed 18% after 10 cycles.
Standard Codes Governing Aggregate Tests
In India, aggregates testing is governed under the Indian Standard (IS) developed by the Bureau of Indian Standards (BIS) with the following main codes:
IS 383:2016 – Specification for coarse and fine aggregates from natural sources for concrete.
IS 2386 (Parts 1-8):1963 – Methods of test for aggregates for concrete, which comprises: Particle size and shape (Part 1); Deleterious materials (Part 2); Mechanical properties (Crushing, Impact, and Abrasion properties) (Part 4); Soundness and Alkali reactivity (Parts 5-7).
IS 2430:1986 – Method of sampling of aggregates for testing.
These codes ease the use of aggregates in concrete and construction throughout India with uniformity, reliability, and quality control with respect of construction materials.
Conclusion
Aggregates are the basis of strong and durable construction. Before purchasing aggregates, you need to conduct all the above tests to achieve structural strength, stability, and longevity in any construction project. More practically, it is advisable to hire a reliable construction company that also offers building material supply. Brick & Bolt understands that high-quality aggregates are the key to improving the strength and durability of your construction. They carefully select both fine and coarse aggregates, ensuring that contractors can get exactly what they need for any application. With top-quality materials and hassle-free delivery, Brick & Bolt is your trusted aggregate supplier. Order now and get fast delivery.