The Digital CBR Testing Machine provides precise, automated California Bearing Ratio testing of subgrade soils, sub-base materials, and base-course aggregates used in highway and airfield pavement construction. This single-speed digital loading frame eliminates the variability inherent in manual CBR testing, delivering consistent penetration rates and accurate load measurements essential for reliable pavement thickness design calculations.

The CBR test simulates traffic loading on pavement layers by driving a standard plunger into a compacted soil specimen at a controlled rate, measuring the penetration resistance. The load required to achieve specified penetration depths (2.5mm and 5.0mm) is compared to the load required for standard crushed stone, yielding the CBR percentage that directly determines required pavement thickness for a given traffic volume and soil support.

This digital machine maintains the standard 1.25mm/minute penetration rate through a precision motor-driven loading frame, ensuring compliance with IS 2720 Part 16, ASTM D1883, and BS 1377 test procedures. The digital load indicator displays penetration force in real-time, with automatic recording of critical 2.5mm and 5.0mm penetration loads. This eliminates the reading errors common with manual proving ring setups while dramatically improving testing efficiency.

Pavement Design Applications:

• Laboratory CBR testing of compacted subgrade soils for highway pavement design
• Quality control testing of granular sub-base and base materials
• Soaked and unsoaked CBR determination for swelling soil assessment
• Airport runway and taxiway foundation bearing capacity evaluation
• Soil stabilization effectiveness verification through comparative CBR testing

The loading frame accommodates standard 150mm diameter CBR moulds with adjustable platen height for various specimen configurations. Digital penetration depth indicator and load readout provide clear, unambiguous test data. The single-speed configuration offers reliable operation for laboratories conducting routine CBR testing per established standards. Includes all necessary accessories for immediate testing capability.