Aggregate Crushing Value Test Report: Standards, Methods, and Interpretation

An aggregate crushing value test report documents the measured resistance of construction aggregates to crushing under a standardized compressive load, serving as a key acceptance criterion for concrete, asphalt pavement, and road base materials. This guide explains the applicable standards, sample requirements, testing procedures, and result interpretation used by accredited third-party laboratories when issuing crushing value test reports.

Technical Overview

The crushing value (also referred to as the crushing indicator or aggregate crushing value, ACV) expresses the resistance of an aggregate to crushing under a gradually applied compressive load. It is calculated as the percentage by mass of fines produced when a prepared aggregate fraction is loaded in a steel cylinder, with a lower value indicating stronger, more crush-resistant aggregate. Because aggregates form the structural skeleton of concrete and asphalt mixtures, the crushing value is one of the most widely specified mechanical quality indicators in construction materials acceptance testing.

The crushing value reflects the intrinsic strength of the parent rock as well as the degree of weathering, micro-cracking, and weakness introduced during crushing and processing. It is therefore used to predict performance under heavy traffic loads, repeated stress cycles, and compaction. Principal testing standards include GB/T 14685 and GB/T 14684 for building aggregates, JTG E42 (Test Methods of Aggregate for Highway Engineering, procedure T 0316) and JGJ 52 for highway and building works, BS 812-110 for the aggregate crushing value, BS 812-111 for the ten percent fines value, IS 2386 Part 4, and related EN and ASTM framework documents for aggregate mechanical properties. Accredited third-party laboratories issue crushing value test reports for quality control, tender compliance, and acceptance purposes.

Testing Samples

Coarse Aggregate (Crushed Stone and Natural Gravel)

The standard specimen is a narrow, single-size fraction of coarse aggregate. Under JTG E42 (T 0316), particles of 9.5 mm to 13.2 mm are used, while BS 812-110 specifies the 10 mm to 14 mm fraction. The sample is washed to remove dust, air-dried or oven-dried to the standard moisture condition, and reduced by splitting to obtain a representative test portion, typically requiring approximately 3 kg to 5 kg of coarse aggregate submitted to the laboratory.

Fine Aggregate and Manufactured Sand

For manufactured sand and fine aggregates, the crushing indicator is determined on graded fractions, commonly 4.75–2.36 mm, 2.36–1.18 mm, 1.18–0.60 mm, and 0.60–0.30 mm, in accordance with GB/T 14684. Each fraction is tested separately, and the crushing indicator is calculated from the mass of crushed fines generated under a prescribed plunger load. This test is essential because manufactured sand often contains weak parent-rock particles that degrade during mixing and compaction.

Special and Alternative Aggregates

Crushing value determinations are also applied to railway ballast, road base and subbase materials, recycled coarse aggregate produced from construction and demolition waste (GB/T 25177), and lightweight aggregates. For these materials, the sampling fraction and acceptance limits are defined by the specific product or project standard, and the report must clearly state which specification the results are judged against.

Testing Items

A typical crushing value test report covers the following test items and informational elements:

• Aggregate crushing value (ACV) of the specified single-size coarse aggregate fraction.
• Crushing indicator of manufactured sand or fine aggregate by size fraction.
• Ten percent fines value (TFV) where a load-based strength index is required.
• Sieve analysis of the specimen before testing and of the crushed product after testing.
• Comparison of measured values with the acceptance limits of the governing standard.
• Laboratory identification, sampling location and date, sample description and source, test standard cited, apparatus description, test date, calculation data, result rounding, and the signature of authorized signatories.

Crushing value testing is frequently combined with complementary mechanical tests such as Los Angeles abrasion (ASTM C131 / EN 1097-2), soundness, flakiness and elongation index, and particle density determination, giving a complete mechanical profile of the aggregate on a single report.

Testing Methods

Apparatus and Specimen Preparation

The standard apparatus consists of a hardened steel cylinder with an internal diameter of 150 mm, a fitted plunger and base plate, a compression testing machine of adequate capacity and verified force accuracy, a round tamping rod, a 2.36 mm test sieve, and a balance readable to 0.1 g. The aggregate is prepared to the specified size fraction, dried to the required condition, and reduced to a representative test portion.

Test Procedure

• Fill the measure with aggregate in three approximately equal layers, compacting each layer uniformly with the tamping rod.
• Level the surface, position the plunger, and place the assembly in the compression machine.
• Apply the compressive load uniformly to the specified total force. Under BS 812-110 and JTG E42 (T 0316), the load is taken to 400 kN, with BS 812-110 requiring the load to be reached over approximately 10 minutes.
• Hold the load momentarily as specified, then release it and remove the load completely.
• Extract the crushed specimen and sieve it over the 2.36 mm sieve, taking care to avoid agglomerating the fines.
• Weigh the mass of particles passing the 2.36 mm sieve to the nearest 0.1 g.
• Repeat the determination on a second specimen as a parallel check.

Calculation and Precision

The crushing value is calculated as the ratio of the mass of fines passing the 2.36 mm sieve to the total mass of the original specimen, expressed as a percentage. Duplicate determinations must agree within the precision limits stated in the standard, typically on the order of one to two percentage points; if the difference exceeds the allowable range, additional specimens are tested and the procedure reviewed. The ten percent fines value, when required, is determined by interpolating the force that produces exactly 10 percent fines and is reported in kN rather than as a percentage.

Interpretation of Results

Acceptance limits depend on the application and the governing standard. Representative requirements include the following:

• GB/T 14685 classifies crushed stone and gravel by crushing indicator: Class I not greater than 10 percent, Class II not greater than 20 percent, and Class III not greater than 30 percent.
• GB/T 14684 limits the crushing indicator of manufactured sand to approximately 20, 25, and 30 percent for Class I, II, and III respectively.
• For asphalt pavements under JTG F40, coarse aggregate crushing values are commonly limited to about 26 percent for high-class surface courses, with slightly higher allowances of about 28 percent for lower road classes and around 30 percent for base materials.
• Cement concrete pavements and high-strength structural concrete typically require crushing values of roughly 10 to 16 percent depending on traffic classification and design strength.
• Railway ballast and other heavy-duty applications impose stricter project-specific limits.

The report should always state the applicable limit alongside the measured value so that a clear pass or fail judgment can be made.

Applications

Crushing value test reports are used throughout the construction materials supply chain and engineering project lifecycle, including the following applications:

• Quarry and aggregate producer quality control, verifying that processed crushed stone and manufactured sand meet declared classification grades before shipment.
• Acceptance testing of coarse and fine aggregate deliveries at concrete batching plants for structural and pavement concrete.
• Asphalt mixture design and production control, confirming that surface, binder, and base course aggregates meet JTG F40 or project specifications.
• Highway base and subbase construction, where the crushing value governs the long-term load-bearing capacity of unbound and stabilized layers.
• Railway engineering, for the qualification of ballast and trackbed aggregates.
• Recycled aggregate certification, supporting the reuse of construction and demolition waste in accordance with GB/T 25177.
• Tender documentation, third-party conformity assessment, supervision inspections, and dispute resolution between contractors, owners, and suppliers.

FAQ

What is a crushing value test report?

It is a formal document issued by an accredited third-party laboratory that records the measured resistance of an aggregate to crushing under a standardized compressive load, together with the test standard, apparatus, calculation data, acceptance limit, and a pass or fail judgment.

Which standards govern crushing value testing?

Commonly applied standards include GB/T 14685, GB/T 14684, JTG E42 (T 0316), JGJ 52, BS 812-110 and BS 812-111, IS 2386 Part 4, and the broader EN and ASTM framework for aggregate mechanical properties. The governing standard depends on the material type, end use, and project location.

How much aggregate should be submitted for testing?

A representative sample of approximately 3 kg to 5 kg of the specified single-size coarse fraction is generally sufficient. For manufactured sand crushing indicator testing and combined mechanical test packages, laboratories usually request larger samples, and it is advisable to confirm quantities in advance.

What crushing value is acceptable?

Acceptance depends on the application. High-class concrete and pavement surface aggregates typically require values near 10 to 16 percent, asphalt surface courses around 26 percent, and general base materials up to about 30 percent. The report must always be judged against the limit stated in the applicable specification.

How does the crushing value differ from the ten percent fines value?

The crushing value is the percentage of fines produced at a fixed load of 400 kN, whereas the ten percent fines value is the load in kN required to produce exactly 10 percent fines. The two tests are complementary strength indices, and both are defined in the BS 812 series.

Can results from different standards be directly compared?

Only indicatively. Although procedures are similar, differences in specimen grading, compaction, loading rate, and sieving aperture mean that results from different standards should not be substituted for one another in contractual or acceptance decisions.

How long does testing take?

The crushing value determination itself is completed within a few hours once the specimen is dried and conditioned. Including sample registration, drying, duplicate determinations, and report review, accredited third-party laboratories typically issue reports within three to seven working days, subject to their workload and any combined test items.