Before any road construction or pavement project begins, one important question needs answering: is the soil strong enough to support what’s being built? Understanding soil strength and bearing capacity at an early stage can help prevent costly delays, design changes, and long-term structural issues.
This is why the CBR test plays such a key role in construction and civil engineering. The California Bearing Ratio test provides engineers and contractors with reliable data on soil performance, supporting informed decisions during planning, site investigation, and pavement design.
To help navigate the range of providers offering this essential testing service, we’ve put together a Top 10 list of CBR testing companies. These organisations support road and pavement construction through soil testing, bearing assessment, and on-site field investigations. Before exploring the list, it’s useful to understand what CBR testing is, how the test procedure works, and why it matters.
What Is CBR Testing?
What is CBR testing? CBR testing, short for the California Bearing Ratio test, is a recognised geotechnical test method used to assess the bearing capacity of soils. It is most commonly applied in highway and road construction projects, pavement design, and subgrade evaluation, where understanding ground behaviour is critical.
The CBR test procedure measures the resistance to penetration of a prepared soil sample using a cylindrical plunger and calibrated apparatus. The force required to penetrate the soil is compared against a standard crushed rock reference material. The resulting CBR value is usually expressed as a percentage, with a higher CBR value indicating stronger material capable of supporting heavier loads.
The test was first developed by the California State Highway Department, originally part of the California Division of Highways, and later adopted internationally as a standard test for soils used in road and pavement construction.
CBR testing can be carried out as a laboratory test or as an in-situ CBR test. In-situ testing, also known as on-site or field testing, measures soil strength directly at the test location, while laboratory testing allows comparison of equivalent CBR values under controlled conditions.
Why the CBR Test Is Used
The CBR test is used to determine how well a soil will perform under load. Engineers rely on CBR data to:
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Calculate the CBR value required for pavement thickness design
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Evaluate soil type, particle size, and suitability for use as subgrade
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Assess strength and bearing capacity for highways and access roads
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Support design decisions during construction of roads and pavements
The test measures how soil particles resist penetration, helping engineers understand how the ground will behave once construction traffic and long-term loading are applied.
CBR testing may also be used alongside other methods, such as the plate bearing test, plate load test, or DCP test, to provide a broader picture of ground performance.
Top 10 CBR Testing Companies & Services
1. cbrtesting.uk
cbrtesting.uk is a specialist provider focused exclusively on CBR test services and California Bearing Ratio assessment for road construction and civil engineering projects. Their work supports pavement design, subgrade evaluation, and early-stage site investigation.
They offer both laboratory CBR testing and in-situ CBR test services. On-site testing allows engineers to evaluate soil strength directly within the test area, while laboratory testing supports controlled calculation and comparison of results.
By following recognised CBR test procedures, including use of a plunger and comparison against standard crushed rock material, the company delivers reliable CBR test values used to assess bearing capacity of soils.
2. cbrtesting.com
cbrtesting.com provides California Bearing Ratio test services for pavement, highway, and infrastructure schemes. Their testing services are commonly used to estimate the CBR value of soils intended for use in road construction projects.
Both laboratory test and in-situ options are available. During in-situ CBR testing, the plunger is used to penetrate the soil, measuring resistance under real ground conditions.
These CBR values help engineers make informed decisions about pavement thickness, material selection, and construction methodology. Further insight into specialist CBR testing providers can also be found through professional directories such as The Geologists’ Directory.
3. cbrtestinguk.com
cbrtestinguk.com offers nationwide CBR testing services, supporting projects ranging from local access roads to major highway schemes. Their work focuses on assessing soil strength, bearing capacity, and suitability for road and pavement construction.
Testing can be carried out on-site as an in-situ CBR test or as a laboratory CBR assessment. This allows engineers to compare test values across different soil samples and conditions.
Their results are used to determine the CBR value required for pavement design and specification.
4. SOCOTEC
SOCOTEC is a major provider of geotechnical and materials testing services, with CBR testing forming part of a wider testing process. Their work supports construction and civil engineering projects where understanding soil performance is essential.
CBR testing is undertaken as either a laboratory test or in-situ test, with results included in professional test reports used for road construction and pavement assessment.
CBR data may also be used alongside plate bearing and plate load tests to evaluate overall ground stiffness.
5. Southern Testing
Southern Testing provides soil testing, laboratory analysis, and field test services. Their CBR test work supports pavement design, foundation planning, and infrastructure development.
CBR testing is used to assess whether the subgrade is suitable or requires improvement. The resulting CBR test values, expressed as a percentage, help engineers evaluate bearing capacity and long-term pavement performance.
6. Tensar U.K.
Tensar U.K. specialises in soil reinforcement and pavement engineering solutions. While not a testing laboratory, CBR values are central to their approach to road and pavement construction.
CBR data is used to evaluate soil strength, understand loading behaviour, and optimise pavement design. Both in-situ CBR and laboratory-derived values may be referenced during design.
7. Perry Testing
Perry Testing delivers on-site materials and geotechnical testing services. Their CBR test is performed during live construction to verify compliance with specification.
Testing may be carried out as an in-situ CBR test, measuring resistance to penetration directly at the test location, often alongside plate bearing test data.
8. Simtec Materials Testing
Simtec Materials Testing provides UKAS-accredited testing services, including standard CBR testing for highways and infrastructure projects.
CBR testing follows recognised test procedures and supports engineers in calculating the CBR value required for pavement and subgrade design.
9. Hixtra Ltd
Hixtra Ltd specialises in in-situ CBR test and plate load test services. Their field-based approach allows soil performance to be assessed directly within the test area.
Using a plunger to penetrate the soil, the test evaluates bearing capacity under real site conditions.
10. Gilsen Co.
Gilsen Co. provides geotechnical and materials testing services that support CBR testing, foundation design, and road construction.
CBR testing is carried out as part of wider site investigation works, helping engineers understand soil type, particle behaviour, and response to loading.
Conclusion
CBR testing remains a cornerstone of soil assessment for construction of roads and pavements. Whether carried out as a laboratory CBR test or an in-situ CBR test, the results play a critical role in design, specification, and long-term performance.
Selecting a competent provider ensures CBR values are accurate, meaningful, and fit for purpose—helping projects move forward with confidence and reduced risk.
