Highways laboratory

Surrey County Council's Merrow Laboratory was established in 1965 as a service for the Local Authority, but it has become a versatile group undertaking impartial testing on behalf of both internal and external clients worldwide.

The laboratory provides a comprehensive range of testing covering, but not limited to, asphalt materials, aggregates and soils as well as providing materials advice, training and site testing/investigations. Our services are available to all. Please see below to find out about the services we offer.


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Our accreditation to provide services

We are accredited by the United Kingdom Accreditation Service (UKAS) for both laboratory and on-site testing in accordance with International Standard ISO/IEC 17025:2017. You can download our Schedule of Acccreditation (PDF) on the UKAS website from UKAS for full details.

Main services we provide

Please see below for details of the following main services that our laboratory provides: bituminous testing, aggregate testing, soils testing, site sampling and testing and site investigations.

Bituminous testing

We provide the following services for bituminous testing:

  • Binder recovery, penetration, and softening point
  • Soluble binder content by recovery
  • Particle size distribution (Grading)
  • Cohesion testing (Vialit pendulum)
  • Resistance to permanent deformation - confined dynamic loading under vacuum (VRLAT)
  • Resistance to permanent deformation - unconfined dynamic loading (RLAT)
  • Cyclic compression test
  • Stiffness – test applying indirect tension to cylindrical specimens (IT-CY)
  • Hot sand test for the adhesivity of binder on precoated chippings for HRA
  • Wheel tracking using a small size device
  • Bulk density - dry - saturated surface dry (SSD) - sealed specimen - by dimensions
  • Maximum density - Volumetric method
  • Air voids content
  • Marshall testing

Aggregate testing

We provide the following services for aggregate testing:

  • Particle density and water absorption
  • Apparent (bulk) density of filler in kerosene
  • Particle size distribution
  • Flakiness index
  • Classification for the constituents of coarse recycled aggregate
  • Water content
  • Magnesium sulphate test
  • Frost heave
  • Resistance to fragmentation by the Los Angeles Method
  • Resistance to wear (micro-Deval)
  • Sampling from stockpiles

Soils testing

We provide the following services for soils testing:

  • California Bearing Ratio (CBR)
  • Moisture content
  • Liquid limit
  • Plastic limit
  • Plasticity index
  • Particle size distribution – wet and dry sieving
  • Dry density/moisture content relationship
  • Uniformity coefficient
  • Sampling earthworks materials - from stockpiles - from laid material

Site sampling and testing

We provide the following services for site sampling and testing:

  • White line testing
  • Sampling
  • Temperature measurements
  • Laying records
  • Texture depth by the sand-patch method
  • Macrotexture using a volumetric patch technique
  • Surface regularity using a rolling straight-edge

Site investigations

We provide the following services for site investigations:

  • Skid/slip resistance value (pendulum test)
  • SCRIM
  • Micro grip testing
  • SROH compliance
  • Determination of the thickness of a bituminous pavement - destructive measurement
  • Clegg Impact Hammer
  • LWD testing
  • CBR
  • Coring
  • DCP testing

Other services

Other services offered by the laboratory include expert guidance on material selection, material recycling, sustainability, carbon reduction, audits of contractors' work to ensure compliance with specifications and standards, trials and evaluations as well as research and development.


How much do we charge for these services?

Please contact us to discuss your requirements and we can provide you with a bespoke quote. This is so we can advise, where necessary, which testing methods are relevant.


How do I request one of these services?

Please contact Jon Tanzili, Laboratory and Survey Team Leader, in the first instance to request a service and/or quote, by emailing: highways@surreycc.gov.uk


What is the turnaround time for providing these services?

Turnaround times are mutually agreed with the client depending on specific project requirements.


Contacting us for further information

For further information, including for minimum sample masses for any specific test prior to delivery, please either email us at highways@surreycc.gov.uk or to speak with us, please see our contact us page for the telephone number and ask for the Laboratory and Survey Team.

Our offices are based in Merrow, Guildford. Further information about the site, including address, can be found on our Merrow Complex webpage.