CALIFORNIA BEARING RATIO TEST (FIELD TYPE) AZA0914

Description

Understanding the Field CBR Test

The California Bearing Ratio (CBR) is an empirical penetration test that compares the resistance of soil to that of a standard crushed rock. In the field CBR test:

1. Surface Preparation
   The test location is levelled and loose material is removed.

2. Surcharge Loading
   Surcharge weights are applied to simulate the anticipated pavement load.

3. Penetration
   A standard 50 mm diameter piston is forced into the soil at a controlled rate (typically 1.25 mm/min) using a hydraulic jack.

4. Force Measurement
   The force required to reach penetrations of 2.5 mm and 5.0 mm is measured using a proving ring or load cell.

5. CBR Calculation

   CBR (%)=Measured LoadStandard Load×100\text{CBR (\%)} = \frac{\text{Measured Load}}{\text{Standard Load}} \times 100CBR (%)=Standard LoadMeasured Load​×100

A higher CBR value indicates a higher soil bearing capacity.

The AZA0914 Field CBR Test provides a realistic assessment of soil strength under actual field conditions, eliminating errors caused by sample disturbance during laboratory testing.

Key Features of AZA0914 Field CBR Apparatus

• Robust Portable Loading Frame
  Designed for stability and durability in demanding site conditions.

• Hydraulic Jack System
  High-capacity hydraulic jack ensures controlled and consistent penetration force.

• Standard Penetration Piston
  50 mm diameter hardened steel piston in accordance with standards.

• Accurate Force Measurement

  • Calibrated proving ring with dial gauge

  • Optional load cell with digital display

• Precise Penetration Measurement
  Dial gauge with fine resolution for accurate depth readings.

• Extension Rods
  Allow testing at different depths below ground level.

• Surcharge Weights
  Simulate pavement and traffic loads for realistic testing.

• Stable Base Plate
  Ensures proper load transfer during testing.

• Portable Carrying Case
  Facilitates easy transportation between test locations.

Applications

• Road and highway pavement design

• Airfield and runway subgrade evaluation

• Quality control of subgrade and base layers

• Soil stabilization assessment (lime, cement, etc.)

• On-site geotechnical investigations

Standards Compliance

• IS 2720 (Part 31):1971 (Reaffirmed 2010) – Field CBR Test

• ASTM D1883 – Principles applicable for CBR calculation

• AASHTO T 193 – California Bearing Ratio

Technical Specifications

Model: AZA0914
Test Method: Field California Bearing Ratio (CBR) Test
Application: In-situ evaluation of subgrade and base course soils
Country of Origin: Made in India

Loading System

• Portable loading frame suitable for field use

• Hydraulic jack capacity: 5 tonne or 10 tonne (as required)

Penetration Piston

• Diameter: 50 mm

• Material: Steel

Force Measurement

• Option 1: Proving ring (≈ 50 kN) with dial gauge (0.01 mm LC)

• Option 2: Load cell with digital indicator

Penetration Measurement

• Dial gauge: 25 mm travel, 0.01 mm least count

• Extension rods: Included

Surcharge Weights

• Type: Slotted

• Typical set: 2.5 kg, 5 kg, 10 kg

Accessories

• Base plate (circular or square)

• Carrying case for field transport

Frequently Asked Questions (FAQ)

Q1: What is the purpose of the AZA0914 Field CBR test?
A: It determines the CBR value of soils directly at site, providing a realistic measure of bearing capacity for pavement design.

Q2: Why perform CBR testing in the field instead of the laboratory?
A: Field testing avoids sample disturbance and reflects actual in-situ soil conditions.

Q3: What does the CBR value indicate?
A: It indicates the relative strength of soil; higher values mean stronger bearing capacity.

Q4: What components are included in AZA0914?
A: Loading frame, hydraulic jack, penetration piston, proving ring or load cell, penetration dial gauge, extension rods, surcharge weights, and base plate.

Q5: Which standards does AZA0914 comply with?
A: IS 2720 (Part 31) and aligned with ASTM D1883 and AASHTO T 193.