AZA 0914 CALIFORNIA BEARING RATIO TEST (FIELD TYPE)

Description

AZA 0914 California Bearing Ratio Test (Field Type): On-Site Soil Evaluation by Azalab

The Azalab AZA 0914 California Bearing Ratio (CBR) Test (Field Type) apparatus is a robust and portable system designed for the direct determination of the California Bearing Ratio (CBR) value of subgrade and base course soils in their in-situ condition. Unlike laboratory CBR tests, which require sample extraction and preparation, the field CBR test provides a rapid and cost-effective method for assessing the bearing capacity of soils directly at the construction site. This is particularly crucial for large-scale road and airfield projects across India, where variations in soil conditions can significantly impact pavement performance. The AZA 0914 apparatus allows engineers to make informed decisions regarding pavement design and construction, ensuring the long-term stability and durability of the infrastructure.

Understanding the Field CBR Test and Its Significance

The California Bearing Ratio (CBR) test is an empirical penetration test that evaluates the relative bearing capacity of a soil compared to a standard crushed rock. The test involves:

1. Surface Preparation: The test location is leveled, and any loose material is removed.
2. Surcharge Loading: Surcharge weights, simulating the anticipated pavement load, are placed around the test area to replicate field conditions.
3. Penetration: A standard piston (typically 50 mm diameter) is forced into the soil at a controlled rate (e.g., 1.25 mm/min) using a hydraulic jack or a loading frame.
4. Force Measurement: The force required to achieve specific penetrations (typically 2.5 mm and 5.0 mm) is measured using a proving ring or a load cell.
5. CBR Calculation: The measured forces are then compared to standard load values for crushed rock at the same penetrations. The CBR value is expressed as a percentage: CBR = (Test Load / Standard Load) x 100 The higher the CBR value, the greater the bearing capacity of the soil.

The AZA 0914 Field CBR Test provides a direct measure of soil strength under field conditions, eliminating the potential errors associated with sample disturbance during transportation and laboratory preparation. This is crucial for accurately assessing the suitability of subgrade soils to support pavements and for determining the required thickness of pavement layers.

Key Features of the AZA 0914 Field CBR Test Apparatus for Reliable On-Site Testing

The Azalab AZA 0914 Field CBR Test apparatus is engineered for durability, portability, and accurate performance in demanding field environments:

• Robust Loading Frame: A sturdy, portable loading frame, typically with a hydraulic jack, provides the necessary force for penetration. The frame is designed for stability and ease of operation in the field.
• Hydraulic Jack: A high-capacity hydraulic jack (e.g., 5-tonne or 10-tonne capacity) allows for controlled and consistent penetration of the piston.
• Penetration Piston: A standard 50 mm diameter steel piston is used for penetration.
• Proving Ring/Load Cell: A calibrated proving ring (e.g., 50 KN capacity) or a load cell accurately measures the applied force. A dial gauge (e.g., 0.01 mm least count) is used with the proving ring to measure deflection.
• Penetration Dial Gauge: A dial gauge (e.g., 25 mm travel, 0.01 mm least count) measures the penetration depth.
• Extension Rods: Extension rods allow for testing at various depths.
• Surcharge Weights: A set of slotted surcharge weights (e.g., 2.5 kg, 5 kg, 10 kg) simulates the pavement load.
• Base Plate: A circular or square base plate provides a stable platform for the loading frame.
• Carrying Case: A sturdy carrying case facilitates transportation to different field sites.

Applications and Standards Compliance in the Indian Context: The Azalab AZA 0914 Field CBR Test is essential for:

• Road Construction: Evaluating the bearing capacity of subgrade and base course materials for flexible and rigid pavements.
• Airfield Construction: Assessing the suitability of soils for supporting aircraft loads.
• Pavement Design: Determining the required thickness of pavement layers based on the CBR value.
• Soil Stabilization: Evaluating the effectiveness of soil stabilization techniques (e.g., lime or cement treatment).
• Quality Control: Ensuring that soil materials meet design specifications.

The equipment is designed and manufactured to comply with relevant national and international standards:

• IS 2720 (Part 31):1971 (Reaffirmed 2010): Indian Standard Methods of Test for Soils – Method of Test for California Bearing Ratio Test.
• ASTM D1883: Standard Test Method for California Bearing Ratio (CBR) of Laboratory-Compacted Soils. (While this refers to laboratory tests, the principles and calculations are applicable to the field test).
• AASHTO T 193: The California Bearing Ratio.

Azalab’s Commitment to Quality and Infrastructure Development: Azalab is committed to providing high-quality, reliable testing equipment that supports the development of robust infrastructure across India. The AZA 0914 Field CBR Test apparatus reflects our dedication to accuracy, durability, and ease of use in challenging field conditions. By providing engineers with essential data for pavement design, we contribute to the construction of safer and more durable roads and airfields. Our equipment is built to stringent quality standards and is backed by comprehensive customer support.

Specifications:

• Model: AZA 0914
• Test Method: Field California Bearing Ratio (CBR) Test
• Application: Evaluation of subgrade and base course soils for road and airfield pavement design.
• Loading Frame: Portable, robust construction for field use.
• Hydraulic Jack:
  • Capacity: 5-tonne or 10-tonne (or as per requirement).
  • Provides controlled penetration force.
• Penetration Piston:
  • Diameter: 50 mm (standard).
  • Material: Steel.
• Force Measurement:
  • Option 1: Proving Ring (e.g., 50 KN capacity) with dial gauge (0.01 mm least count).
  • Option 2: Load Cell with digital display.
• Penetration Measurement:
  • Dial Gauge: 25 mm travel, 0.01 mm least count.
• Extension Rods: Included for testing at various depths.
• Surcharge Weights:
  • Type: Slotted.
  • Weights: e.g., 2.5 kg, 5 kg, 10 kg (set).
• Base Plate: Circular or square, providing a stable platform.
• Carrying Case: Sturdy case for transportation.
• Standards Compliance: IS 2720 (Part 31):1971 (Reaffirmed 2010), principles of ASTM D1883 and AASHTO T 193.
• Country of Origin: Made in India.

FREQUENTLY ASKED QUESTIONS (FAQ):

• Q: What is the purpose of the Field CBR test?
  • A: It is used to determine the California Bearing Ratio (CBR) value of subgrade and base course soils directly in the field, providing a measure of their bearing capacity for pavement design.
• Q: What is the CBR value?
  • A: The CBR value is a percentage that represents the relative bearing capacity of a soil compared to a standard crushed rock. A higher CBR indicates a stronger soil.
• Q: Why is it important to perform the CBR test in the field?
  • A: Field tests provide a more accurate assessment of soil strength under in-situ conditions, avoiding errors associated with sample disturbance that can occur during laboratory testing.
• Q: What are the key components of the AZA 0914 apparatus?
  • A: Key components include a loading frame, hydraulic jack, penetration piston, proving ring/load cell, penetration dial gauge, extension rods, and surcharge weights.
• Q: What standards does this equipment comply with?
  • A: It is designed to comply with IS 2720 (Part 31) and is aligned with the principles of ASTM D1883 and AASHTO T 193.
• Q: How is the CBR value calculated?
  • A: The CBR is calculated by comparing the force required to penetrate the soil to the force required to penetrate a standard crushed rock at the same penetration depths (typically 2.5 mm and 5.0 mm).
• Q: What are surcharge weights used for?
  • A: Surcharge weights simulate the load of the pavement structure, replicating field conditions and providing a more accurate assessment of soil bearing capacity.