The Aggregate Crushing Value (ACV) test is a critical quality control method to assess the strength of coarse aggregates used in road construction and concrete production. This article explains the test procedure, calculations, and how to interpret results to ensure compliance with international standards like BS 812-110:1990 and ASTM C131/C131M-20.
What is the Aggregate Crushing Value Test?
The ACV test measures an aggregate’s resistance to crushing under gradually applied compressive loads. It determines:
- Suitability for high-stress applications (e.g., road base layers).
- Durability against mechanical degradation during transportation and compaction.
- Compliance with construction specifications (e.g., maximum ACV limits).
Equipment and Materials Required
- Steel Cylinder: 150 mm diameter with plunger and base plate.
- Compression Testing Machine: Capacity ≥400 kN.
- Sieves: 12.5 mm and 10 mm for sample preparation.
- Balance: Accuracy ±1 g.
- Oven: For drying aggregates at 105–110°C.
Step-by-Step Procedure
1. Sample Preparation
- Dry aggregates in an oven until constant weight.
- Sieve to retain particles between 12.5 mm and 10 mm.
- Fill the cylinder with 3 layers of aggregate, each tamped 25 times with a standard tamping rod.
2. Loading and Crushing
- Place the cylinder in the compression machine.
- Apply a 40-ton load at 4 tons/min.
- Hold the load for 10 minutes, then release.
3. Sieving and Weighing
- Remove crushed material and sieve through a 2.36 mm sieve.
- Weigh the retained fraction (W₁) and passing fraction (W₂).
Calculations and Interpretation
Aggregate Crushing Value Formula:ACV (%)=W2W1+W2×100\text{ACV (\%)} = \frac{W_2}{W_1 + W_2} \times 100ACV (%)=W1+W2W2×100
Acceptable Limits:
| Application | Maximum ACV |
|---|---|
| Road base (heavy traffic) | ≤30% |
| Concrete aggregates | ≤45% |
| Low-stress pavements | ≤50% |
A higher ACV indicates weaker aggregates prone to crushing.
Why Follow BS 812 and ASTM Standards?
- BS 812-110:1990: Specifies a 10-minute loading time and 40-ton load for consistency.
- ASTM C131/C131M-20: Uses a 12.5–9.5 mm aggregate size and different sieving criteria.
- Key Difference: ASTM requires a 2.36 mm sieve, while BS 812 uses a 2.36 mm sieve for fines.
Case Study: Improving Road Durability in Australia
A highway project in Queensland replaced aggregates with an ACV of 38% (failing BS 812) with stronger aggregates (ACV 25%). Result:
- 20% reduction in road surface cracks over 3 years.
- 15% lower maintenance costs due to reduced aggregate breakdown.
Common Errors to Avoid
- Inadequate Compaction: Under-tamping layers skews ACV results lower.
- Moisture Content: Wet aggregates falsely increase strength; always oven-dry samples.
- Overloading: Exceeding 40 tons overestimates aggregate weakness.
Tips for Accurate Testing
- Calibrate Equipment: Verify compression machine accuracy annually.
- Repeat Tests: Perform triplicate tests for consistency (discard outliers).
- Documentation: Record sieve sizes, load rates, and environmental conditions.
Conclusion
The Aggregate Crushing Value test is indispensable for selecting durable aggregates in civil engineering projects. Prioritize aggregates with ACV ≤30% for heavy-load applications and always adhere to regional standards. Regular testing during material sourcing prevents costly construction failures.
Related Articles
Mobile concrete crushing equipment manufacturers
Mobile concrete crushing equipment is designed to efficiently crush and recycle concrete, asphalt, and other construction materials on site. This equipment helps to reduce the...
calcite processing stone grinding mill machine
Calcite is a mineral that is commonly found in sedimentary rocks, and it is widely used in various industries such as construction, paint, paper, plastics,...
Concrete vibrating screen equipment in South Africa
Concrete vibrating screen equipment is used in South Africa to separate concrete by size or density. It is a versatile piece of equipment that can...
Basalt crusher used in basalt aggregate production processing plant
Basalt crusher is the mining equipments widely used in basalt resizing and pulverizing industry, usually in basalt aggregate producing process plant. Basalt Rocks introduction: Basalt...
Bauxite Grinding Mill
Bauxite is a chemical or biochemical rock rich in aluminum minerals. The main mineral components are diaspore, boehmite and gibbsite. It is mainly formed by...
How to configure the 200tph sand and gravel aggregate production line
In order to achieve the output requirement of 200 tons per hour, it is necessary to make a very scientific and reasonable arrangement of the...
Flow chart of lithium ore crushing, grinding and screening process
Lithium ore from mines is lumpy. The maximum size of ore blocks from open pit mining is 1000mm~1500mm, and the maximum size of ore blocks...
Crushers capable of crushing 15cm rocks finely
C&M Mining Machinery’s crushers equipment capable of crushing 10-15cm rocks finely,Jaw crusher for crushing various mid-hard and abrasive weak materials.It's compressive strength of the material...
Rock quarry stone crusher for sale in Philippines
A rock quarry stone crusher is a machine used to crush and break large stones into smaller pieces for use in construction, landscaping, and other...
used sand washing machine plant in india
In India, the demand for sand washing machines has been steadily increasing due to the growing construction industry and the need for clean and quality...